Flue gas desulfurization and denitrification ultra-low emission DCS control system

Abstract

The invention provides a flue gas desulfurization and denitrification ultra-low emission DCS control system, belongs to the technical field of flue gas purification, and solves the technical problems that an existing desulfurization and denitrification DCS control system cannot realize deep synergy of desulfurization and denitrification and cannot perform ultra-low emission with accurate prediction and efficient response. The system comprises a boiler, an SCR denitration reactor connected with a flue gas outlet of the boiler, and an air pre-heater fixedly mounted at an outlet of the SCR denitration reactor, wherein an outlet of the air pre-heater is fixedly connected with a dust remover. According to the invention, through the arrangement of the data acquisition assembly and under the action of the collaborative optimization assembly, the system realizes an ammonia escape feedforward-compensation mechanism, the negative coupling between the denitration control unit and the desulfurization control unit is broken, the blockage of ammonium bisulfate is effectively prevented, the reliability of the desulfurization control unit is improved, and the service life of the desulfurization control unit is prolonged. Data acquisition, working condition identification, prediction and energy efficiency optimization are integrated on a unified DCS platform, and closed-loop intelligent control from sensing to decision making to execution is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of flue gas purification, and relates to a flue gas desulfurization and denitrification control system, in particular to a flue gas desulfurization and denitrification ultra-low emission DCS control system. BACKGROUND

[0002] The desulfurization and denitrification DCS control system is mainly used for removing nitrogen oxides in the emission of a thermal power plant, and the denitrification principle thereof is that flue gas reacts with sprayed ammonia under the action of a catalyst to be converted into water and nitrogen, so that the purpose of removing nitrogen oxides is achieved.

[0003] Through retrieval, it is found that a flue gas desulfurization and denitrification reconstruction post-flue gas system control optimization method (application number: CN201711244599.3; publication number: CN107940501A) is disclosed in Chinese patent documents. The control optimization method increases the oxygen correction amount control loop and loop interface of the flue gas desulfurization and denitrification reconstruction post of the thermal power unit, the secondary air damper opening correction amount control loop and loop interface of the flue gas desulfurization and denitrification reconstruction post of the thermal power unit, the induced draft fan output correction amount control loop and loop interface of the flue gas desulfurization and denitrification reconstruction post of the thermal power unit, and the booster fan output correction amount control loop and loop interface of the flue gas desulfurization and denitrification reconstruction post of the thermal power unit in the control logic configuration of the distributed control system DCS of the thermal power unit.

[0004] Although the control optimization method disclosed in the patent corrects the fan damper control, the control system can only control the damper independently. Since denitrification and desulfurization are serially connected process units, if the ammonia gas required for denitrification escapes excessively, it will react with SO3 in the desulfurization control unit to generate ammonium bisulfate, causing the desulfurization control unit equipment to be blocked, corroded and reduced in efficiency. Moreover, the induced draft fan damper control has a large lag and fluctuation, which easily leads to excessive consumption of materials or instantaneous emission exceeding the standard. SUMMARY

[0005] The purpose of the present application is to solve the above-mentioned problems existing in the prior art, and to provide a flue gas desulfurization and denitrification ultra-low emission DCS control system. The technical problem to be solved by the present application is how to realize deep collaboration of desulfurization and denitrification and to provide an ultra-low emission DCS control system capable of accurate prediction and efficient response.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] The application discloses a flue gas desulfurization and denitrification ultra-low emission DCS control system, which comprises a boiler, an SCR denitrification reactor connected with the flue gas outlet of the boiler and an air preheater fixedly installed at the outlet of the SCR denitrification reactor.

[0008] The inlet of the SCR denitrification reactor is connected with a soot blower, and the soot blower is electrically connected with a denitrification control unit.

[0009] The SCR denitrification reactor and the absorption tower are externally provided with a data acquisition assembly, and the data acquisition assembly is electrically connected with the denitrification control unit and the desulfurization control unit.

[0010] The data acquisition assembly is connected with the denitrification control unit and the desulfurization control unit through a field bus, the denitrification control unit and the desulfurization control unit are connected with a collaborative optimization assembly through a control network, and the collaborative optimization assembly is connected with a man-machine monitoring assembly through wireless network communication.

[0011] The collaborative optimization assembly comprises:

[0012] A working condition recognition unit is connected with the data acquisition assembly through an OPC protocol and receives real-time process data.

[0013] An ammonia escape feedforward-compensation unit is connected with the working condition recognition unit through a database interface and connected with the denitrification control unit through a control network.

[0014] A predictive control unit is connected with the working condition recognition unit through a real-time database and connected with an energy efficiency optimization unit through an optimization algorithm interface.

[0015] An energy efficiency optimization unit is connected with the denitrification control unit and the desulfurization control unit through a control network and outputs an optimized set value.

[0016] The working principle of the present application: the system continuously collects all sensor and device state data through the data acquisition component, judges the current running state through the working condition identification unit, whether it is in steady state, load increase or load decrease condition, the key variables in the current working condition, such as inlet NOx, flue gas flow, ammonia injection amount, inlet SO2, slurry pH, circulating slurry flow, are input into the predictive control unit, which predicts the outlet NOx and SO2 concentration in the next 5-15 minutes, the energy efficiency optimization unit calculates the ammonia injection amount set value and circulating slurry flow set value that make the total cost lowest and meet the ultra-low emission constraint according to the predicted outlet concentration, current material price and electricity price by solving the energy efficiency model, at the same time, the ammonia escape feedforward-compensation unit reads the real-time data of the ammonia escape instrument before the desulfurization tower, when the ammonia escape concentration exceeds the preset threshold value, such as 2.5ppm, a negative compensation signal is generated, which is superimposed on the ammonia injection amount set value of the denitration control unit, to forcibly reduce ammonia injection and inhibit the generation of ammonium bisulfate from the source, the denitration control unit and the desulfurization control unit receive the set value instructions from the energy efficiency optimization unit, accurately drive the ammonia injection regulating valve, the absorbent supply pump and the circulating pump, and realize stable control of the outlet concentration.

[0017] The data acquisition component comprises:

[0018] NOx analyzers, O2 analyzers, temperature sensors, pressure transmitters and flow meters fixedly installed at the inlet flue of the SCR denitration reactor;

[0019] NOx analyzers, O2 analyzers and ammonia escape analyzers fixedly installed at the outlet flue of the SCR denitration reactor;

[0020] SO2 analyzers, temperature sensors and pressure transmitters fixedly installed at the inlet flue of the absorption tower;

[0021] SO2 analyzers, dust concentration monitors and O2 analyzers fixedly installed at the outlet flue of the absorption tower;

[0022] pH meters, density meters and liquid level meters fixedly installed in the slurry pool area inside the absorption tower;

[0023] Pressure transmitters and flow meters fixedly connected at the outlet pipeline of the oxidation air blower.

[0024] Adopting the above structure, the SO2 analyzer can continuously and accurately monitor and sample the flue gas, wherein the SO2 analyzer is a Siemens ULTRAMAT 23, the NOx analyzer uses NDIR or chemiluminescence method to measure NO and NO2 respectively, the ammonia escape analyzer is a key component for realizing collaborative control, and uses tunable semiconductor laser absorption spectrum technology, which includes a receiving and transmitting component and a purging component, the receiving and transmitting component is installed on both sides of the flue, the transmitting end transmits laser of specific wavelength, and the receiving end detects laser intensity absorbed by ammonia, the purging component includes a purifying air source and a nozzle for continuously purging the optical lens to prevent flue gas pollution, and further, the liquid level meter inside the absorption tower needs to use a non-contact radar liquid level meter or a nuclear liquid level meter due to easy scaling and corrosion of the medium.

[0025] The human-computer monitoring component comprises:

[0026] The operator end is connected with the collaborative optimization component and the data acquisition component through wireless communication;

[0027] The engineer station is connected with the data acquisition component and the collaborative optimization component through a configuration network;

[0028] The historical data server is connected with the data acquisition component and the collaborative optimization component through a database network;

[0029] The stations are connected through a redundant industrial Ethernet switch.

[0030] Through the operator end and the engineer station, the process flow, real-time data, trend curve and alarm information can be displayed, parameter setting, mode switching and manual / automatic operation interface can be provided, and human-computer interaction and control operation are facilitated.

[0031] The inlet of the SCR denitration reactor is also fixedly provided with an ammonia injection grid, the inlet end of the ammonia injection grid is fixedly connected with the discharge end of a mixer, and the inlet end of the mixer is connected with a liquid ammonia storage tank through a dilution fan.

[0032] Adopting the above structure, the ammonia injection grid covers the entire flue cross section, and the mixed gas of ammonia and air is uniformly and accurately injected into the flue gas through multiple branch pipes, so that the nitrogen oxides in the flue gas are fully and uniformly mixed before entering the catalyst layer.

[0033] The oxidation zone of the absorption tower is fixedly connected with the air outlet of an oxidation fan, and the bottom of the absorption tower is provided with a slurry pool area.

[0034] Adopting the above structure, under the action of the oxidation fan, the oxidation air volume is controlled to ensure that the calcium sulfite is fully oxidized into gypsum, the gypsum quality is ensured, the system is prevented from scaling, and the physical environment of the slurry pool is ensured to be stable through monitoring of the agitator and the oxidation fan.

[0035] The outlet flue of the absorption tower is connected with a demister, and the outlet flue of the demister is fixedly connected with a clean smoke baffle;

[0036] The outside of the demister is fixedly connected with a demister flushing pump.

[0037] By the arrangement of the clean smoke baffle, smoke backflow is avoided, and corrosion of the equipment and inner wall in the tower is effectively prevented.

[0038] The slurry pool area comprises a slurry tank, the outlet of the slurry tank is fixedly connected with an absorption tower through a slurry supply pump, the inlet of the slurry tank is fixedly connected with a limestone bin through a ball mill, and the liquid inlet of the slurry tank is further connected with a process water tank through a process water pump;

[0039] The outlet end of the slurry pool area is fixedly connected with the inlet of a discharge pump, and the outlet of the discharge pump is fixedly connected with the inlet end of a gypsum cyclone, the outlet end of the gypsum cyclone is fixedly connected with a vacuum belt conveyor, and the other end of the vacuum belt conveyor is fixedly installed with a gypsum bin.

[0040] By the liquid level meter and the pH meter inside the absorption tower, the limestone slurry supply amount can be controlled through the pH meter, so that the optimal pH value of the slurry is maintained, the desulfurization efficiency and the limestone utilization rate are ensured, and under the action of the density meter, when the slurry density reaches the set value, about 1120-1180 kg / m 3 , it indicates that the gypsum has been fully crystallized, the discharge pump is started to send the gypsum slurry to the dehydration system, fresh water and limestone are supplemented, the process water supplement is controlled through the liquid level meter, the normal liquid level of the slurry pool is maintained, and the system water balance is ensured.

[0041] The denitration control unit is connected with the ammonia injection grid, the dilution fan and the soot blower through hard wiring.

[0042] The desulfurization control unit is connected with the slurry supply pump, the oxidation fan, the agitator and the demister flushing pump through hard wiring.

[0043] By the above structure, the ammonia injection grid is a plurality of independent branches, each region is provided with an independent flow regulating valve, the ammonia injection amount of different regions is adjusted in real time according to the feedback of the flue gas velocity field and concentration field measuring device installed behind the ammonia injection grid, the uneven flue gas condition is compensated, and dynamic and accurate ammonia injection is realized.

[0044] Compared with the prior art, the flue gas desulfurization and denitration ultra-low emission DCS control system has the following advantages:

[0045] 1. In this invention, by setting up the data acquisition component and with the help of the collaborative optimization component, the system realizes the "ammonia escape feedforward-compensation" mechanism, breaks the negative coupling between the denitrification and desulfurization control units, effectively prevents ammonium bisulfate blockage, improves the reliability and lifespan of the desulfurization control unit, integrates data acquisition, operating condition identification, prediction and energy efficiency optimization into a unified DCS platform, realizes closed-loop intelligent control from perception to decision-making to execution, and improves the automation level of the entire flue gas purification system.

[0046] 2. In this invention, by setting up the collaborative optimization component, under the action of the predictive control unit, the system can make advance adjustments according to the trend of changes in operating conditions, significantly reducing the fluctuation of outlet concentration, having a strong ability to resist changes in load and coal quality, ensuring stable compliance of emission concentration, achieving a balance between pollutant removal efficiency and operating energy and material consumption, and significantly reducing the overall operating cost of the system while ensuring ultra-low emissions.

[0047] 3. In this invention, by setting up an ammonia escape feedforward-compensation unit, the ammonia escape feedforward-compensation unit can dynamically correct the ammonia injection setting value of the denitrification control unit according to the ammonia escape concentration monitoring value at the inlet of the desulfurization control unit, forming a feedforward-feedback composite control loop to suppress ammonia escape. Moreover, under the action of the data acquisition component, the multi-source data acquired can be filtered, corrected and fused, and the current boiler load, fuel type and total pollutant load can be identified in real time based on the fused data, ensuring the accuracy of data acquisition. Attached Figure Description

[0048] Fig. 1 This is a schematic diagram of the DCS control system for ultra-low emission flue gas desulfurization and denitrification according to the present invention.

[0049] Fig. 2 This is a schematic diagram of the data acquisition component in this invention.

[0050] In the diagram, 1. Boiler; 2. SCR denitrification reactor; 3. Absorber tower; 4. Air preheater; 5. Soot blower; 6. Ammonia injection grid; 7. Mixer; 8. Liquid ammonia storage tank; 9. Dilution fan; 10. Dust collector; 11. Exhaust fan; 12. Desulfurization baffle; 13. Circulation pump; 14. Oxidation fan; 15. Demister; 16. Clean smoke baffle; 17. Demister flushing pump; 18. Limestone silo; 19. Slurry tank; 20. Slurry supply pump; 21. Discharge pump; 22. Hydrocyclone; 23. Vacuum belt conveyor; 24. Data acquisition component. Detailed Implementation

[0051] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0052] Please refer to Figs. 1-2 The application discloses a flue gas desulfurization and denitrification ultra-low emission DCS control system, which comprises a boiler 1, an SCR denitrification reactor 2 connected with the flue gas outlet of the boiler 1, an air preheater 4 fixedly installed at the outlet of the SCR denitrification reactor 2, an absorption tower 3, a soot blower 5, an ammonia injection grid 6, a mixer 7, a liquid ammonia storage tank 8, a dilution fan 9, a dust remover 10, an induced draft fan 11, a desulfurization baffle 12, a circulating pump 13, an oxidation fan 14, a demister 15, a clean flue gas baffle 16, a demisting flushing pump 17, a limestone bin 18, a slurry tank 19, a slurry supply pump 20, a discharge pump 21, a cyclone 22, a vacuum belt conveyor 23, a data acquisition assembly 24, a denitrification control unit and a desulfurization control unit, the outlet of the air preheater 4 is fixedly connected with the dust remover 10, the outlet of the dust remover 10 is fixedly connected with the induced draft fan 11, the other end of the induced draft fan 11 is fixedly installed with the desulfurization baffle 12, and the outlet of the desulfurization baffle 12 is connected with the absorption tower 3 through the circulating pump 13, and the absorption tower 3 is electrically connected with the desulfurization control unit.

[0053] The inlet of the SCR denitrification reactor 2 is connected with the soot blower 5, and the soot blower 5 is electrically connected with the denitrification control unit.

[0054] The data acquisition assembly 24 is installed outside the SCR denitrification reactor 2 and the absorption tower 3, and the data acquisition assembly 24 is electrically connected with the denitrification control unit and the desulfurization control unit.

[0055] The data acquisition assembly 24 is connected with the denitrification control unit and the desulfurization control unit through a field bus, the denitrification control unit and the desulfurization control unit are connected with a collaborative optimization assembly through a control network, and the collaborative optimization assembly is connected with a human-machine monitoring assembly through wireless network communication.

[0056] The collaborative optimization assembly comprises:

[0057] A working condition identification unit is connected with the data acquisition assembly 24 through an OPC protocol and receives real-time process data.

[0058] An ammonia escape feedforward-compensation unit is connected with the working condition identification unit through a database interface and is connected with the denitrification control unit through a control network.

[0059] A predictive control unit is connected with the working condition identification unit through a real-time database and is connected with an energy efficiency optimization unit through an optimization algorithm interface.

[0060] The energy efficiency optimization unit is connected with the denitrification control unit and the desulfurization control unit through the control network and outputs an optimized set value.

[0061] The data acquisition assembly 24 comprises:

[0062] NOx analyzer, O2 analyzer, temperature sensor, pressure transmitter and flow meter fixedly installed at the inlet flue of the SCR denitration reactor 2;

[0063] NOx analyzer, O2 analyzer and ammonia escape analyzer fixedly installed at the outlet flue of the SCR denitration reactor 2;

[0064] SO2 analyzer, temperature sensor and pressure transmitter fixedly installed at the inlet flue of the absorption tower 3;

[0065] SO2 analyzer, dust concentration monitor and O2 analyzer fixedly installed at the outlet flue of the absorption tower 3;

[0066] pH meter, density meter and liquid level meter fixedly installed inside the absorption tower 3;

[0067] Pressure transmitter and flow meter fixedly connected at the outlet pipeline of the oxidation fan 14;

[0068] Further, the SO2 analyzer can continuously and accurately monitor and sample the flue gas, wherein the SO2 analyzer is a Siemens ULTRAMAT 23, the NOx analyzer uses NDIR or chemiluminescence method and can measure NO and NO2 respectively, the ammonia escape analyzer is a key component for realizing collaborative control and uses tunable semiconductor laser absorption spectrum technology, which includes a receiving and transmitting component and a blowing component, the receiving and transmitting component is installed on both sides of the flue, the transmitting end transmits laser of specific wavelength, the receiving end detects laser intensity absorbed by ammonia gas, the blowing component includes a purified air source and a nozzle, which continuously blows to the optical lens to prevent flue gas pollution, and the liquid level meter inside the absorption tower 3 needs to use a non-contact radar liquid level meter or a nuclear liquid level meter due to easy scaling and corrosion of the medium.

[0069] The human-computer monitoring component includes:

[0070] Operator end: connected with the collaborative optimization component and the data acquisition component 24 through wireless communication;

[0071] Engineer station: connected with the data acquisition component 24 and the collaborative optimization component through a configuration network;

[0072] Historical data server: connected with the data acquisition component 24 and the collaborative optimization component through a database network;

[0073] Each station is connected through a redundant industrial Ethernet switch;

[0074] Through the operator end and the engineer station, the process flow, real-time data, trend curve and alarm information can be displayed, and parameter setting, mode switching and manual / automatic operation interface can be provided, which facilitates human-computer interaction and control operation.

[0075] The inlet of the SCR denitration reactor 2 is also fixedly installed with an ammonia injection grid 6, and the inlet end of the ammonia injection grid 6 is fixedly connected with the outlet end of a mixer 7, the inlet end of the mixer 7 is connected with a liquid ammonia storage tank 8 through a dilution fan 9, the ammonia injection grid 6 covers the entire flue cross section, and the mixed gas of ammonia and air is uniformly and accurately injected into the flue gas through multiple branch pipes, so that it is fully and uniformly mixed with the nitrogen oxides in the flue gas before entering the catalyst layer.

[0076] The oxidation zone of the absorption tower 3 is fixedly connected with the outlet of an oxidation fan 14, and the bottom of the absorption tower 3 is provided with a slurry pool area.

[0077] The outlet flue of the absorption tower 3 is connected with a mist eliminator 15, and the outlet flue of the mist eliminator 15 is fixedly connected with a clean flue baffle 16;

[0078] The outside of the mist eliminator 15 is fixedly connected with a mist eliminator washing pump 17.

[0079] The slurry pool area includes a slurry tank 19, the outlet of the slurry tank 19 is fixedly connected with the absorption tower 3 through a slurry supply pump 20, the inlet of the slurry tank 19 is fixedly connected with a limestone bin 18 through a ball mill, and the liquid inlet of the slurry tank 19 is also connected with a process water tank through a process water pump;

[0080] The outlet end of the slurry pool area is fixedly connected with the inlet of a discharge pump 21, and the outlet of the discharge pump 21 is fixedly connected with the inlet end of a gypsum cyclone 22, the outlet end of the gypsum cyclone 22 is fixedly connected with a vacuum belt conveyor 23, and the other end of the vacuum belt conveyor 23 is fixedly installed with a gypsum bin.

[0081] The denitration control unit is connected with the ammonia injection grid 6, the dilution fan 9, and the soot blower 5 through hardwiring;

[0082] The desulfurization control unit is connected with the slurry supply pump 20, the oxidation fan 14, the agitator, and the mist eliminator washing pump 17 through hardwiring.

[0083] Working principle: The system continuously collects all sensor and equipment state data through the data acquisition component 24, judges the current running state to be in a steady state, a load increase or a load decrease state through the working condition identification unit, inputs the key variables in the current working condition, such as the inlet NOx, flue gas flow, ammonia injection amount, inlet SO2, slurry pH, and circulating slurry flow, into the predictive control unit, and rolls forward to predict the outlet NOx and SO2 concentrations in the next 5-15 minutes. The energy efficiency optimization unit dynamically calculates the ammonia injection amount set value and the circulating slurry flow set value that make the total cost lowest and meet the ultra-low emission constraint according to the predicted outlet concentration, the current material price and the electricity price by solving the energy efficiency model. At the same time, the ammonia escape feedforward-compensation unit reads the real-time data of the ammonia escape instrument before the desulfurization tower. When the ammonia escape concentration exceeds the preset threshold, such as 2.5 ppm, a negative compensation signal is generated and superimposed on the ammonia injection amount set value of the denitration control unit to forcibly reduce the ammonia injection and inhibit the generation of ammonium bisulfate from the source. The denitration control unit and the desulfurization control unit receive the set value instructions from the energy efficiency optimization unit to accurately drive the ammonia injection regulating valve, the absorbent supply pump and the circulating pump 13, thereby realizing stable control of the outlet concentration. In this way, the working principle of the flue gas desulfurization and denitration ultra-low emission DCS control system is completed.

[0084] Example 2

[0085] When the boiler 1 is in a load increase state:

[0086] The system detects that the load instruction is rising, and the working condition identification unit determines that it is in a "load increase" state.

[0087] The predictive control unit predicts that the outlet NOx will have an over-standard risk after 3 minutes according to the current rising flue gas flow and inlet NOx concentration.

[0088] At the same time, the energy efficiency optimization unit calculates that the optimal ammonia injection increment under the current working condition should be X kg / h.

[0089] The denitration control unit and the desulfurization control unit receive the optimized ammonia injection set value and increase the ammonia injection regulating valve opening in advance.

[0090] Due to the advance action, when the flue gas flow actually reaches the peak value, the ammonia injection amount has been synchronized, effectively avoiding the instantaneous over-standard of the outlet NOx, and realizing smooth transition

[0091] In this embodiment, the ammonia escape feedforward-compensation unit continuously monitors. If the ammonia escape has an upward trend due to the increase of ammonia injection, the ammonia injection set value will be adjusted to ensure that it is always within a safe range.

[0092] To sum up, in the application, through the setting of the data acquisition component 24 and under the action of the cooperative optimization component, the system realizes the "ammonia escape feedforward-compensation" mechanism, breaks the negative coupling between the denitration and desulfurization control units, effectively prevents the ammonium bisulfate blockage, improves the reliability and service life of the desulfurization control unit, integrates the data acquisition, working condition identification, prediction and energy efficiency optimization on the unified DCS platform, realizes the closed-loop intelligent control from perception to decision-making to execution, improves the automation level of the entire flue gas purification system, and solves the technical problems that the existing desulfurization and denitration DCS control system cannot realize the deep cooperation of desulfurization and denitration, and cannot realize the precise prediction and efficient response of the ultra-low emission.

[0093] The specific embodiments described herein are merely illustrative of the principles of this application. Numerous modifications or adaptations will be readily apparent to those skilled in the art of this application without departing from the spirit or scope of the application as defined by the following claims.

Claims

1. A flue gas desulfurization and denitrification ultra-low emission DCS control system, comprising a boiler (1), an SCR denitrification reactor (2) connected with the flue gas outlet of the boiler (1), and an air preheater (4) fixedly installed at the outlet of the SCR denitrification reactor (2), characterized in that, The outlet of the air preheater (4) is fixedly connected with a dust remover (10), the outlet of the dust remover (10) is fixedly connected with an induced draft fan (11), the other end of the induced draft fan (11) is fixedly installed with a desulfurization baffle (12), the outlet of the desulfurization baffle (12) is connected with an absorption tower (3) through a circulating pump (13), and the absorption tower (3) is electrically connected with a desulfurization control unit; The inlet of the SCR denitration reactor (2) is connected with a soot blower (5), and the soot blower (5) is electrically connected with a denitration control unit; The SCR denitration reactor (2) and the absorption tower (3) are externally installed with a data acquisition assembly (24), and the data acquisition assembly (24) is electrically connected with the denitration control unit and the desulfurization control unit; The data acquisition assembly (24) is connected with the denitration control unit and the desulfurization control unit through a field bus, the denitration control unit and the desulfurization control unit are connected with a collaborative optimization assembly through a control network, and the collaborative optimization assembly is connected with a man-machine monitoring assembly through wireless network communication; The collaborative optimization assembly comprises: A working condition recognition unit connected with the data acquisition assembly (24) through an OPC protocol and receiving real-time process data; An ammonia escape feedforward-compensation unit connected with the working condition recognition unit through a database interface and connected with the denitration control unit through a control network; A predictive control unit connected with the working condition recognition unit through a real-time database and connected with an energy efficiency optimization unit through an optimization algorithm interface; An energy efficiency optimization unit connected with the denitration control unit and the desulfurization control unit through a control network and outputting optimized set values.

2. The flue gas desulfurization and denitrification ultra-low emission DCS control system according to claim 1, characterized in that, The data acquisition assembly (24) comprises: NOx analyzers, O2 analyzers, temperature sensors, pressure transmitters and flow meters fixedly installed at the inlet flue of the SCR denitration reactor (2); NOx analyzers, O2 analyzers and ammonia escape analyzers fixedly installed at the outlet flue of the SCR denitration reactor (2); SO2 analyzers, temperature sensors and pressure transmitters fixedly installed at the inlet flue of the absorption tower (3); SO2 analyzers, dust concentration monitors and O2 analyzers fixedly installed at the outlet flue of the absorption tower (3); pH meters, density meters and liquid level meters fixedly installed at the internal pulp pool area of the absorption tower (3); Pressure transmitters and flow meters fixedly connected at the outlet pipeline of the oxidation air blower (14).

3. The flue gas desulfurization and denitrification ultra-low emission DCS control system according to claim 1, characterized in that, The man-machine monitoring assembly comprises: An operator end connected with the collaborative optimization assembly and the data acquisition assembly (24) through wireless communication; An engineer station connected with the data acquisition assembly (24) and the collaborative optimization assembly through a configuration network; A historical data server connected with the data acquisition assembly (24) and the collaborative optimization assembly through a database network; The stations are connected through a redundant industrial Ethernet switch.

4. The flue gas desulfurization and denitrification ultra-low emission DCS control system according to claim 1, characterized in that, The inlet of the SCR denitration reactor (2) is also fixedly installed with an ammonia injection grid (6), the inlet end of the ammonia injection grid (6) is fixedly connected with the discharge end of a mixer (7), and the inlet end of the mixer (7) is connected with a liquid ammonia storage tank (8) through a dilution air blower (9).

5. The flue gas desulfurization and denitrification ultra-low emission DCS control system according to claim 1, characterized in that, The oxidation zone of the absorption tower (3) is fixedly connected with the air outlet of an oxidation fan (14), and the bottom of the absorption tower (3) is provided with a slurry pool area.

6. The flue gas desulfurization and denitrification ultra-low emission DCS control system according to claim 5, characterized in that, The outlet flue of the absorption tower (3) is connected with a demister (15), and the outlet flue of the demister (15) is fixedly connected with a clean smoke baffle (16); The outside of the demister (15) is fixedly connected with a demisting flushing pump (17).

7. The flue gas desulfurization and denitrification ultra-low emission DCS control system according to claim 5, characterized in that, The slurry pool area comprises a slurry tank (19), the outlet of the slurry tank (19) is fixedly connected with the absorption tower (3) through a slurry supply pump (20), the feed inlet of the slurry tank (19) is fixedly connected with a limestone bin (18) through a ball mill, and the liquid inlet of the slurry tank (19) is further connected with a process water tank through a process water pump; The outlet end of the slurry pool area is fixedly connected with the feed inlet of a discharge pump (21), and the discharge outlet of the discharge pump (21) is fixedly connected with the feed end of a gypsum cyclone (22), the discharge end of the gypsum cyclone (22) is fixedly connected with a vacuum belt conveyor (23), and the other end of the vacuum belt conveyor (23) is fixedly installed with a gypsum bin.

8. The flue gas desulfurization and denitrification ultra-low emission DCS control system according to claim 1, characterized in that, The denitration control unit is connected with the ammonia injection grid (6), the dilution fan (9) and the soot blower (5) through hardwiring; The desulfurization control unit is connected with the slurry supply pump (20), the oxidation fan (14), the agitator and the demisting flushing pump (17) through hardwiring.

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