A denitration improvement method and device based on ozone oxidation

Abstract

The present application belongs to the technical field of flue gas pollutant treatment, and specifically discloses a denitration improvement method and equipment based on ozone oxidation, which comprises the following steps: demarcating an ozone reaction channel on the waste gas treatment pipeline to be transformed; demarcating multiple dosing points on the ozone reaction channel; starting the boiler to introduce flue gas into the waste gas treatment pipeline and starting the ozone delivery device to introduce ozone into the waste gas treatment pipeline; adjusting the communication state of the dosing points and the ozone delivery device, monitoring the amount of nitrogen oxides in the waste gas treatment pipeline and the corresponding amount of ozone introduced under each communication state; constructing a proportional function according to the amount of nitrogen oxides and the amount of ozone; and controlling the waste gas treatment pipeline to treat the flue gas generated by the current boiler through the proportional function. The present application has the following advantages: through the multi-point ozone dynamic dosing and the flexible collaborative mechanism of SCR, the integrated efficient control of denitration, deodorization and mercury removal under the condition of low-temperature and high-humidity waste incineration flue gas is realized, and the treatment efficiency is significantly improved, and the energy consumption and operation and maintenance costs are reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flue gas pollutant treatment, in particular to a denitration improvement method and equipment based on ozone oxidation. BACKGROUND

[0002] At present, SNCR denitration process is generally used in waste incineration power plants, and low-temperature SCR process is used in some newly built projects. SNCR process is mature but has low denitration efficiency, which easily leads to boiler fouling, corrosion and ammonia escape; SCR needs flue gas to be reheated to about 400 DEG C, which has high energy consumption and the catalyst is easy to be deactivated, and has high maintenance cost. With the tightening of NOx emission limit value, the existing technology is insufficient in efficiency and limited in arrangement under the condition of low-temperature and high-humidity flue gas, and it is difficult to realize integrated control of denitration, deodorization and mercury removal.

[0003] Therefore, a denitration improvement method and equipment based on ozone oxidation are provided to solve the above problems. SUMMARY

[0004] The present application aims to provide a denitration improvement method and equipment based on ozone oxidation to solve or improve the problem that it is difficult to realize integrated control of high-efficiency denitration, deodorization and mercury removal under low-temperature flue gas.

[0005] Therefore, the first aspect of the present application provides a denitration improvement method and equipment based on ozone oxidation.

[0006] The second aspect of the present application provides an equipment.

[0007] The first aspect of the present application provides a denitration improvement method and equipment based on ozone oxidation, comprising the following steps: demarcating an ozone reaction channel passing through an SCR reactor in a waste gas treatment pipeline to be transformed on the waste gas treatment pipeline; demarcating a plurality of dosing points connected with an ozone delivery device in sequence on the ozone reaction channel along the flow direction of flue gas inside the waste gas treatment pipeline; connecting a boiler waste gas outlet and the waste gas treatment pipeline through an inlet flue; starting the boiler and introducing flue gas into the waste gas treatment pipeline through the inlet flue, starting the ozone delivery device and introducing ozone into the waste gas treatment pipeline through the dosing points; adjusting the communication state of the dosing points and the ozone delivery device, monitoring the amount of nitrogen oxides in the waste gas treatment pipeline and the amount of corresponding ozone introduced under each communication state; constructing a proportional function according to the amount of nitrogen oxides and the amount of ozone; controlling the waste gas treatment pipeline to treat the flue gas generated by the current boiler by the proportional function, so as to adjust the amount of nitrogen oxides in the flue gas discharged at the end of the waste gas treatment pipeline to within a preset range value.

[0008] In any of the above technical solutions, the step of sequentially demarcating multiple dosing points on the ozone reaction channel, which are connected to the ozone delivery device, comprises: setting the dosing points on the ozone reaction channel before the semi-dry reactor and the bag dust collector in the flue gas treatment pipeline along the flow direction.

[0009] In any of the above technical solutions, the ozone reaction channel comprises a first branch connecting the dosing points to the absorption tower in the flue gas treatment pipeline and a second branch connecting the dosing points to the absorption tower via the SCR reactor.

[0010] In any of the above technical solutions, the step of controlling the flue gas treatment pipeline to treat the flue gas generated by the current boiler by the proportional function comprises: obtaining the component content of the flue gas in the inlet flue at each time; calculating the required ozone amount corresponding to the component content of the flue gas at the current time by the proportional function; configuring the ozone input amount of each dosing point according to the calculated ozone amount, and selecting one of the first branch and the second branch to be conducted.

[0011] In any of the above technical solutions, ozone is injected into the flue gas treatment pipeline before the flue gas enters the semi-dry reactor, and the ozone and the flue gas are mixed by the first gas-gas mixer at the dosing point.

[0012] In any of the above technical solutions, ozone is injected into the flue gas treatment pipeline after the flue gas flows out of the semi-dry reactor and before it enters the bag dust collector, and the ozone and the flue gas are mixed by the second gas-gas mixer at the dosing point.

[0013] In any of the above technical solutions, ozone is injected into the flue gas treatment pipeline after the flue gas flows out of the bag dust collector and before it enters the SCR reactor, and the ozone and the flue gas are mixed by the third gas-gas mixer at the dosing point.

[0014] In any of the above technical solutions, the first branch or the second branch is selected according to the following rules: when the required ozone amount is greater than the ozone production of the ozone delivery device, the second branch is conducted; when the required ozone amount is less than the ozone production of the ozone delivery device, the first branch is conducted.

[0015] In any of the above technical solutions, the denitration improvement method further comprises the following steps: when the nitrogen oxide amount at the end of the flue gas treatment pipeline is within the preset range, adjusting the ozone input amount of each dosing point by the controller until the ozone production of the ozone delivery device required is minimized.

[0016] The second aspect of the present application provides a device, comprising: an exhaust gas treatment pipeline for purifying nitrogen oxides in flue gas discharged from a boiler exhaust port and discharging to the outside; an ozone delivery device for generating ozone required for purifying nitrogen oxides; and a dosing point for introducing the generated ozone into the exhaust gas treatment pipeline and following the flow of flue gas in the ozone reaction channel.

[0017] The present application has the following beneficial effects compared with the prior art:

[0018] By sequentially defining multiple dosing points along the direction of flue gas flow inside the exhaust gas treatment pipeline, the ozone injection position and amount can be controlled, different flue gas conditions and pollutant concentrations can be dynamically matched, and the denitration efficiency is effectively improved, solving the problems of low SNCR denitration efficiency and ammonia escape;

[0019] Based on the ozone oxidation technology, the flue gas does not need to be heated to a high temperature state, significantly reducing the flue gas heating energy consumption, overcoming the shortcomings of high energy consumption and high cost of low-temperature SCR process;

[0020] By real-time monitoring of the nitrogen oxide content in the exhaust gas treatment pipeline and constructing a proportional function, accurate ozone injection and dynamic regulation and control are realized, the ozone consumption is reduced, the economy is further improved, and the problems of high maintenance cost and short maintenance period caused by catalyst deactivation are solved;

[0021] The integrated control of denitration, deodorization and mercury removal can be realized simultaneously under the conditions of low-temperature and high-humidity waste incineration flue gas, solving the problems of insufficient multi-pollutant simultaneous removal capability and limited arrangement of the prior art;

[0022] The flexible switching mechanism of ozone and SCR path is adopted, the service life of the SCR system is prolonged, and the overall maintenance cost is reduced.

[0023] Additional aspects and advantages of embodiments according to the present application will become apparent from the following description with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0024] The above and / or additional aspects and advantages of the present application will become apparent and more readily appreciated from the following description, taken in conjunction with the accompanying drawings, in which:

[0025] Figure 1 The method flowchart of the present application;

[0026] Figure 2 The ozone segmented dosing control flowchart of the present application;

[0027] Figure 3 The double-branch switching control flowchart of the present application;

[0028] Figure 4Optimization flow chart for minimum ozone consumption of the present application

[0029] Figure 5 Abnormal condition handling flow chart of the present application

[0030] Figure 6 Device structure schematic diagram of the present application.

[0031] wherein, Figures 1-6 The correspondence between the reference signs and the component names is as follows:

[0032] 1 inlet flue, 2 first online NOx concentration meter, 3 first gas-gas mixer, 4 semi-dry method reactor, 5 second gas-gas mixer, 6 bag-type dust collector, 7 induced draft fan, 8 third gas-gas mixer, 9 second online NOx concentration meter, 10 SCR reactor, 11 absorption tower, 12 online pH meter, 13 liquid discharge pipeline, 14 supplementary alkali liquid pipeline, 15 flow meter, 16 spray circulation, 17 heater, 18 chimney, 19 oxygen source, 20 ozone generation system, 21 cooling water system, 22 gas flow meter, 23 online ozone concentration meter. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more clearly understood, the present application will be further described in detail below with reference to the drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0034] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, however, the present application can also be implemented in other ways different from those described herein, therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.

[0035] Please refer to Figures 1-6 , the following describes an improved method and device for denitration based on ozone oxidation.

[0036] As in the background art, at present, most of the waste incineration power plants use SNCR denitration technology for desulfurization and denitration, and some newly built waste incineration power plants use low-temperature SCR denitration technology. The SNCR process is simple and mature, but it has problems such as low denitration efficiency, boiler scaling, water wall corrosion, etc. The low-temperature SCR process has low denitration efficiency, and the reactor is usually arranged after the acid removal and bag dust removal device. Considering that the flue gas temperature needs to be higher than the acid gas dew point temperature by 15℃, the general operating temperature is 150℃-180℃, and some incineration flue gas needs to be reheated to raise the flue gas temperature to about 400℃ to achieve the best catalytic temperature. However, in actual operation, sulfur, heavy metals and dust in waste incineration flue gas can easily cause deactivation of low-temperature catalysts, and the cost of replacing catalysts is very high, so the process design and operation management capability are very high, resulting in poor actual effect.

[0037] Ozone oxidation denitration deodorization and mercury removal process is a very promising and rapidly promoted flue gas denitration deodorization and mercury removal process, which has unique advantages in low-temperature flue gas denitration. It has fast reaction speed, high denitration efficiency, good deodorization effect, high mercury removal rate, safe and stable system operation, no secondary pollution, can realize simultaneous denitration deodorization and mercury removal, and has no catalyst deactivation problem and ammonia escape problem. The system is equipped with an oxygen generation system and does not need flue gas reheating. Except for electric power and absorption of alkali solution consumption, there is no other consumption.

[0038] In the past two years, the power industry and the steel industry have introduced ultra-low emission standards for air pollutants, which have higher requirements for flue gas denitration. The common denitration technologies are SNCR and SCR, which are widely used in various industries, but these two technologies have problems such as low efficiency, ammonia escape, and limited modification site in low-temperature flue gas environment, which cannot meet the needs of all flue gas denitration, deodorization and mercury removal. Ozone advanced oxidation method is a new type of denitration, deodorization and mercury removal technology, which has been gradually promoted based on its own advantages.

[0039] The oxidation process is the process of oxidizing NO in flue gas to soluble nitrogen oxides such as nitrogen dioxide by ozone. Since the decomposition rate of ozone itself is relatively slow below 200℃, the reaction of NO with ozone is very fast. Therefore, only the optimal ozone concentration needs to be considered. Generally speaking, the cost of ozone production materials accounts for 70% of the operating cost of ozone denitration. Reducing operating costs requires strict control of ozone usage. Make NO just completely oxidized to nitrogen dioxide and dinitrogen pentoxide.

[0040] The basic principle of ozone advanced oxidation flue gas multi-removal includes that multiple pollutants can be oxidized by ozone advanced oxidation system at a lower temperature, and become easily soluble products such as sulfur trioxide, oxidized mercury and nitrogen dioxide, nitrogen trioxide, nitrogen pentoxide, etc. High-valence nitrogen oxides enter the washing tower for wet absorption.

[0041] In view of the above-mentioned problems, embodiments of the first aspect of the present application propose an improved denitration method based on ozone oxidation. In some embodiments of the present application, as shown in the figure, the improved denitration method based on ozone oxidation comprises the following steps: Figures 1-5

[0042] S101, demarcate an ozone reaction channel passing through the SCR reactor in the waste gas treatment pipeline to be modified; along the flow direction of the flue gas inside the waste gas treatment pipeline, demarcate a plurality of dosing points connected to the ozone delivery device on the ozone reaction channel in sequence.

[0043] Here, the ozone reaction channel is a flue section before the flue gas enters the SCR reactor, especially including a section where the high-temperature flue gas still has oxidation activity, and a section where the flue gas flow is relatively stable and suitable for uniform mixing. By demarcating multiple ozone dosing points in this channel, not only can the reaction control be realized step by step, but also the existing flue structure characteristics can be matched according to local conditions, avoiding large-scale equipment replacement or causing pressure loss structure changes.

[0044] Demarcate the ozone oxidation channel in the straight pipe section, elbow section or hot standby bypass section before the flue gas enters the SCR reactor; the channel length can be determined according to the SCR front flue gas residence time, target dosing section reaction depth and catalyst load, usually retaining 3-6 seconds of oxidation reaction time. The dosing points are arranged in sequence according to the flue gas flow direction, in three regions such as the pre-section, middle section and SCR front section; each dosing point is connected to an independent or modular ozone delivery pipeline, which can be started and stopped or flow regulated individually to realize differentiated control; the point installation structure is preferably a static gas mixer or a high-speed injection mixing cavity to ensure that ozone and NO gas form a rapid and uniform mixing zone locally, promoting instantaneous oxidation reaction.

[0045] As can be seen above, in a garbage incineration power plant with a daily flue gas treatment capacity of 300,000 Nm 3 / h, the 10-meter flue section before the SCR reactor can be demarcated as an ozone reaction channel, and three ozone dosing points can be set at 10m, 6m and 2m from the SCR;

[0046] Each point is equipped with a modular ozone generation system, which adjusts the O3 / NO molar ratio to 0.6, 0.4 and 0.2 respectively through feedback control signals to realize the front-heavy and rear-light segmented oxidation strategy;

[0047] ​The first section mainly completes the preliminary conversion of NO to NO2; the second section strengthens the conversion of NO2 and NO to N2O3 and N2O5; and the third section serves as a polishing section to ensure that the NO content at the inlet of the SCR is below the set threshold. Not only is the orderly integration and functional arrangement of the ozone oxidation section in physical space achieved, but a structural foundation is also laid for subsequent steps of precise ozone ratio adjustment, dynamic response to pollutant load changes, and improvement of NOx oxidation conversion rate.

[0048] Specifically, the step of sequentially demarcating multiple dosing points on the ozone reaction channel that are in communication with the ozone delivery device includes:

[0049] Along the flow direction, before the SCR reactor and the semi-dry method reactor and the bag filter in the exhaust gas treatment pipeline, dosing points are arranged on the ozone reaction channel.

[0050] According to the above specific description, the step of sequentially demarcating multiple dosing points on the ozone reaction channel that are in communication with the ozone delivery device is specifically that, along the flue gas flow direction, partitioned dosing points are arranged before the semi-dry method reactor, before the bag filter, and before the SCR reactor, thereby constructing three independently controllable ozone dosing regions of front, middle, and end. This partitioned arrangement scheme first takes full advantage of the high-temperature zone characteristics at the inlet of the semi-dry method reactor, sets the first dosing point at this location, and makes the nitrogen monoxide undergo a preliminary oxidation reaction with ozone before being deacidified, thereby rapidly reducing the original nitrogen monoxide concentration and weakening the competitive effect of sulfur dioxide on the subsequent oxidation path. Next, the second dosing point is set before the inlet of the bag filter, ozone is added in the medium-temperature section to supplement the first section, further conversion of the nitrogen monoxide that has not been completely oxidized is performed, odorous organic matter and elemental mercury are oxidized, and the subsequent filtering unit is used to timely capture the generated oxidation particles to prevent high-valence nitrogen oxides from re-escaping after combining with dust. Finally, the third dosing point is set before the inlet of the SCR reactor for polishing and adding a small amount of ozone, ensuring that the nitrogen oxides entering the catalytic section have been converted into high-valence forms with higher reactivity, significantly reducing the demand for reducing agents and reducing the risk of ammonia escape.

[0051] As can be seen from the above, taking a waste incineration power station as an example, if the SCR reactor is ten meters away from the outlet of the semi-dry method reactor and two meters away from the outlet of the bag filter, the first dosing point can be arranged one meter before the inlet of the semi-dry method reactor, the second dosing point can be arranged one meter before the inlet of the bag filter, and the third dosing point can be arranged zero point five meters before the inlet of the SCR reactor. Each dosing point is in communication with an independent modular ozone generation system, and the central controller adjusts the switch state and ozone injection amount of each dosing point according to the real-time nitrogen oxide concentration and flue gas flow, forms a segmented dosing, step-by-step oxidation, and dynamic control linkage reaction chain, and ultimately achieves the overall goal of low cost, high efficiency, and collaborative multi-pollutant control.

[0052] In any of the above embodiments, the ozone reaction channel comprises a first branch connecting the absorption tower from the dosing point to the flue gas treatment pipeline, and a second branch connecting the absorption tower from the dosing point via the SCR reactor.

[0053] In this embodiment, the ozone reaction channel is jointly formed by the first branch and the second branch in the latter half of the structure, wherein the first branch is branched from the dosing point, directly merges into the absorption tower in the flue gas treatment pipeline through an independent pipe section, forming a bypass channel bypassing the SCR reactor, and the second branch passes through the SCR reactor along the original flue before merging into the absorption tower after the first branch, and the two branches are realized by the switching valve group for online start-stop and flow ratio adjustment.

[0054] The function of the first branch is to allow the flue gas after ozone oxidation to directly enter the absorption tower for liquid phase absorption reaction when the SCR reactor is in a maintenance, low load or insufficient catalyst activity operation state, thereby maintaining continuous denitration, deodorization and mercury removal capacity without relying on catalyst, and converting high-valence nitrogen oxides into nitrate and nitrite in the absorption tower using lye to avoid yellow smoke emission; at the same time, the first branch can reduce system pressure loss and fan energy consumption due to its shorter pipe length and smaller flow resistance, and provide a rapid response channel during instantaneous load fluctuations.

[0055] The second branch undertakes the task of catalytic reduction under normal conditions, when the SCR reactor is working normally and the catalyst is in the best activity interval, ozone is only added at the front end to reduce the concentration of nitrogen monoxide, and nitrogen dioxide and high-valence nitrogen oxides enter the SCR reactor and react with appropriate ammonia to deeply reduce residual nitrogen oxides into nitrogen and water vapor, realizing efficient denitration and inhibiting ammonia escape; the flue gas treated by the catalytic section is then merged with the first branch and enters the absorption tower for end-of-pipe washing, further capturing pollutants that have not been completely converted.

[0056] The two branches are in actual operation according to the online nitrogen oxide concentration, the SCR reactor inlet temperature, the catalyst pressure drop and the absorption tower pH value to comprehensively judge the distribution ratio, specifically, when the catalyst activity is reduced to cause the denitration efficiency to be lower than 70%, the flow distribution ratio is automatically adjusted from 70% of the second branch and 30% of the first branch to 30% of the second branch and 70% of the first branch, so that the end emission is kept stable and meets the standards, the catalyst service life is prolonged and the ammonia consumption is reduced; for example, in the low load operation stage of the waste incineration boiler at night, the second branch can be completely closed, and all the flue gas is sent into the absorption tower through the first branch, so that the ammonium bisulfate deposition and the catalyst pore blockage caused by the SCR reactor under low temperature conditions are avoided. Through the double branch structure, the flexible matching between the denitration process and the equipment state is realized, the ozone utilization rate is improved, the overall energy consumption and the maintenance cost are reduced, and the nitrogen oxide emission concentration is always stably controlled within the preset range value under various complex working conditions.

[0057] S102, the boiler exhaust port and the waste gas treatment pipeline are connected through the gas inlet flue; the boiler is started and the flue gas is introduced into the waste gas treatment pipeline through the gas inlet flue, the ozone delivery device is started and ozone is introduced into the waste gas treatment pipeline through the dosing point.

[0058] Here, by establishing a stable, continuous and controllable ozone oxidation reaction condition, the actual operation condition is provided for the step-by-step conversion of nitrogen oxides. First, the sealed connection between the boiler outlet and the waste gas treatment pipeline is realized through the gas inlet flue, so that the flue gas generated by the boiler combustion can flow into the subsequent denitration device according to the established path. Under the premise of ensuring the sealing property and the high temperature resistance and corrosion resistance, the gas inlet flue is preferably made of heat-resistant steel or alloy composite material, and a temperature-resistant expansion joint or corrugated compensation structure is arranged at the interface to adapt to the thermal expansion and contraction displacement caused by the change of the boiler thermal load, so that the flue gas conveying process does not leak or stress failure.

[0059] After the boiler is normally warmed up and operated, the flue gas is introduced into the waste gas treatment pipeline through the gas inlet flue, and the flue gas mainly contains nitrogen oxides, sulfur dioxide, dust particles, carbon oxides and various organic volatile substances. Since the flue gas temperature at this stage is still at a relatively high level, for example, 250 to 300 degrees Celsius, its reaction activity is strong, and it is suitable for introducing ozone for primary oxidation. At this time, by starting the ozone delivery device, the operation of the modular ozone generation system is controlled according to the set flow program, and the generated ozone is delivered to the multiple dosing points arranged through the ozone gas supply pipeline. Each dosing point is provided with a static mixer or a high-speed airflow jet head, which injects ozone into the main airflow in a uniform distribution manner without interfering with the main flue gas velocity, and forms an oxygen-rich region locally, so as to promote the rapid oxidation of nitrogen oxides, especially nitric oxide, to nitrogen dioxide and higher valence compounds.

[0060] From the above, not only the original NO concentration is reduced in the front end, but also the dependence of the subsequent SCR reactor on the reducing agent is reduced, and the energy saving and responsiveness of the overall denitration system are improved. Specifically, as in the initial start-up period of a waste incineration power plant, when the flue gas temperature stabilizes at about 280 degrees Celsius, it is automatically determined that the ozone reaction effective interval has been reached, triggering the ozone module to start in turn, and sending gas to the three ozone dosing points at ten meters, six meters, and two meters away from the SCR reactor according to the dosing ratio. The first point is preferentially started to establish a reaction pre-zone, and the second and third points decide whether to open or adjust the dosing ratio according to the online NOx concentration feedback value, so as to dynamically adapt to the denitration load under different working conditions. The coordinated start of continuous flue gas conveying and quantitative ozone injection is realized, which not only ensures the smooth progress of the nitrogen oxide oxidation reaction, but also lays a foundation for the preparation of reactants for downstream devices, and has good controllability, stability and practical operation adaptability.

[0061] S103, adjust the communication state between the dosing point and the ozone delivery device, monitor the amount of nitrogen oxides in the exhaust gas treatment pipeline and the amount of ozone corresponding to the communication under each communication state; construct a proportional function according to the amount of nitrogen oxides and the amount of ozone.

[0062] Here, a dynamic response mechanism is established to accurately match the ozone dosing demand under different flue gas composition conditions, and the optimal reaction coupling relationship between nitrogen oxides and ozone is realized. By adjusting the communication state between each dosing point and the ozone delivery device, the specified point can be selected to be opened or closed based on the current working condition, or the ozone injection flow of each point can be adjusted. The purpose is to realize the multi-section ozone quantitative dosing strategy through partition control without affecting the stability of the main gas flow, so as to significantly improve the ozone utilization efficiency and reduce unnecessary energy consumption and reaction redundancy.

[0063] In actual operation, the working state of different dosing points can be adjusted periodically or in real time. For example, in the stage of high flue gas load and high NO concentration, the system will preferentially enable the front and middle ozone dosing points and run at a high ozone flow rate to quickly reduce the NO concentration in the main gas flow. When the flue gas load tends to be stable or the NO concentration is below the set threshold, the front ozone dosing amount is appropriately reduced, and only the end point is retained as a reaction compensation zone to achieve the purpose of energy saving and consumption reduction. The dynamic adjustment of the above communication state can be realized by structures such as electromagnetic valves, variable frequency fans, and flow regulating valves, and is uniformly managed by a central controller.

[0064] In order to quantify the actual contribution of ozone to denitration, the amount of ozone introduced and the residual concentration of nitrogen oxides in the exhaust gas treatment pipeline under each communication state need to be recorded simultaneously. The detection of nitrogen oxides is completed by a distributed online concentration analyzer, which is mainly installed downstream of each ozone mixer to read the mass concentration value of nitrogen oxides in real time. The ozone flow is obtained by a gas mass flow meter and an electric control flow module, and is automatically recorded into the system database. By comparing and analyzing the ozone dosage and the decrease in NOx concentration within a certain period of time, the unit ozone utilization efficiency of different points can be calculated, and a proportional function model between nitrogen oxide concentration and ozone injection amount can be established.

[0065] As can be seen above, under a certain working condition, the ozone injection amount at the first injection point is 10 standard cubic meters per hour, the injection amount at the second injection point is 6 standard cubic meters, and the third point is not opened. Monitoring found that the NOx concentration before SCR decreased from the initial 150 mg / m3 to 72 mg / m3, the system automatically judged that the denitration efficiency of the current injection strategy was 52%, and the ozone amount required for unit NOx removal was calculated based on the cumulative data of the time period before and after, thereby establishing a one-to-one corresponding proportional function. This function not only can be used to evaluate the current reaction efficiency, but also can provide basic parameters for subsequent prediction of injection amount, realizing closed-loop control. The whole link quantification feedback from ozone injection behavior to reaction result is completed, which provides data support for intelligent adjustment and significantly enhances the adaptability and precision of the ozone oxidation denitration strategy.

[0066] S104, controlling the exhaust gas treatment pipeline to treat the flue gas generated by the current boiler by the proportional function, so as to adjust the amount of nitrogen oxides in the flue gas discharged at the end of the exhaust gas treatment pipeline to within a preset range value.

[0067] Here, by establishing an ozone injection closed-loop adjustment mechanism based on feedback control, the emission concentration of nitrogen oxides in the flue gas finally discharged through the exhaust gas treatment pipeline is always maintained within the preset range value required by environmental protection specifications, for example, controlled to be not higher than the ultra-low emission standard of 50 mg / m3. To this end, the proportional function constructed in the previous step is used as the basis of the control strategy, and the total amount of ozone required is dynamically calculated according to the current detected boiler operating state, flue gas flow, nitrogen oxides original concentration and other input variables, and is distributed to each injection point in real time.

[0068] After the proportional function is established, multi-dimensional parameter linkage adjustment can be performed according to the deduction result of the proportional function, including: adjusting the working power of each modular ozone generation system; adjusting the flow valve opening degree of each ozone delivery pipeline; starting and stopping ozone injection points at different positions; and coordinating the frequency of the fan and the flue gas flow rate to match the residence reaction time between ozone and nitrogen oxides. For example, when the instantaneous concentration of flue gas NOx increases due to fluctuations in boiler load, the proportional function determines that the current denitration capacity is insufficient, and immediately responds by increasing the injection flow rate of the first and second ozone injection points to increase the reaction capacity to a level that meets the actual emission requirements.

[0069] In addition, during the stable operation stage of the system, the control strategy does not blindly pursue the lowest emission concentration, but prioritizes ozone injection efficiency according to the target range. When the NOx concentration is below 50 mg / m3 and tends to be 30 mg / m3, the system automatically evaluates whether the denitration gain generated by continued ozone injection is greater than the energy consumption cost. If it is found that the marginal benefit of ozone injection is decreasing and below the cost threshold, the system automatically reduces the gas supply power or closes some points to achieve energy-saving operation.

[0070] As can be seen from the above, for a waste incineration boiler with a flue gas flow of 250,000 standard cubic meters per hour, the proportional function initially sets the O3 / NO molar ratio to 1.0, and the first, second, and third points are allocated 50%, 30%, and 20% of the total injection amount, respectively. When the online NOx concentration detector detects that the pre-SCR concentration rises to 120 mg / m3, the proportional function increases the molar ratio to 1.3, with the first two points being preferentially scheduled, and the third point being compensated and polished according to the actual injection result to ensure that the end NOx concentration stabilizes and falls below 50 mg / m3. Subsequently, the proportional function coefficients are corrected based on the comparison of historical data results to achieve self-adaptive dynamic optimization. This not only enables stable and compliant emissions under varying operating conditions, but also enables optimal control of denitration efficiency under the condition of minimum energy consumption, providing a technical guarantee for the widespread application of ozone oxidation technology in engineering.

[0071] Specifically, the step of treating the flue gas generated by the boiler by the waste gas treatment pipeline through the proportional function control includes:

[0072] At each time, the composition content of the flue gas in the inlet flue is obtained.

[0073] The composition content of the flue gas at the current time is calculated by the proportional function to obtain the required amount of ozone.

[0074] The amount of ozone introduced into each injection point is configured according to the calculated amount of ozone, and one of the first branch and the second branch is selected to be turned on.

[0075] According to the specific description, the composition content of flue gas in the inlet flue is obtained in real time. At each moment, multiple groups of online analyzers installed on the cross section of the inlet flue simultaneously sample and detect the flue gas, and the monitored parameters at least include the mass concentration of nitrogen monoxide, the mass concentration of nitrogen dioxide, the mass concentration of sulfur dioxide, the volume fraction of elemental mercury, the instantaneous temperature of flue gas, and the flow. After the detection signal is transmitted to the central control unit through the high-speed data bus, it is immediately compared with the historical reference data, the abnormal noise points are eliminated, and the flue gas composition vector at the current moment is generated, which serves as the input reference of the proportional function. By comparing the vectors of consecutive periods, the trend of flue gas load change can be further obtained, which provides a reference for subsequent prediction and adjustment.

[0076] The required ozone amount corresponding to the composition content of flue gas at the current moment is calculated by using the proportional function. The proportional function is derived from the mapping relationship between the concentration of nitrogen oxides and the injection amount of ozone established in step S103. The central control unit substitutes the flue gas composition vector into the proportional function, and outputs the theoretical total ozone demand amount by linear interpolation or polynomial regression algorithm. In order to balance the denitration efficiency and energy consumption cost, the total ozone amount is also weighted and corrected according to the concentration of sulfur dioxide, the temperature coefficient and the real-time electricity price, to generate the optimized ozone target value. If the proportion of nitrogen monoxide in the flue gas is high, the function automatically increases the target ozone amount; if the peak value of sulfur dioxide is higher than the set threshold, the function slightly reduces the target ozone amount to reduce non-target consumption and reserve the excess degree of alkali absorption.

[0077] According to the calculation results, the ozone injection amount of each dosing point is configured, and the conduction scheme is selected between the first branch and the second branch. The total ozone target value is distributed to the front, middle and end dosing points according to the preset segmentation coefficient, and the distribution proportion of each segment is corrected in real time according to the online feedback of the concentration of nitrogen oxides. After the distribution is completed, the instruction is issued to adjust the variable frequency power of each ozone generation module, and the electric flow valve of the corresponding conveying pipeline is controlled, so that the actual injection flow and the target flow are kept within an error of not more than 2%. Then, according to the inlet temperature of the SCR reactor, the catalyst pressure drop and the denitration efficiency, the branch selection logic is determined: when the catalyst activity is maintained in the high efficiency interval and the outlet ammonia escape is lower than the set threshold, the second branch is kept open, so that the flue gas passes through the SCR reactor for reduction reaction; when the catalyst temperature is insufficient or the activity decay leads to the decrease of denitration efficiency, the instruction is sent to close the second branch switching valve and open the first branch bypass, so that the flue gas after deep oxidation by ozone directly enters the absorption tower for liquid phase absorption. The branch switching process adopts synchronous action of zero pressure difference quick switching valve, and the switching time is not more than three seconds, so as to ensure that the flue gas flow and pressure fluctuation are kept within the safe allowable range.

[0078] As can be seen from the above, taking full load operation of a waste incineration boiler as an example, the real-time detection of the inlet flue gas NO mass concentration is 160 mg / m3, the NO2 mass concentration is 35 mg / m3, the flue gas flow is 250,000 m3 / h, the theoretical ozone demand is calculated to be 35 Nm3 / h by the proportional function, and the target ozone amount is obtained to be 32 Nm3 / h after optimization correction. Among them, 50% is allocated to the pre-position injection point, 30% is allocated to the middle injection point, and 20% is allocated to the end injection point. At the same time, it is judged that the SCR reactor inlet temperature still remains above 300°C and the denitration efficiency is higher than 85%, and the second branch is maintained to be turned on; if the catalyst bed temperature is detected to be reduced to 220°C and the NOx outlet concentration is increased to 75 mg / m3 after four hours of operation, the first branch is turned on immediately, the ozone flow of the pre-position injection point is adjusted to 20 Nm3 / h, and the ozone flows of the middle and end injection points are adjusted to 8 and 4 Nm3 / h respectively, so as to ensure that the end emission NOx concentration is stably reduced to 45 mg / m3.

[0079] Specifically, before the flue gas enters the semi-dry reactor, ozone is sprayed into the waste gas treatment pipeline, and the ozone and the flue gas are mixed through the first gas-gas mixer at the injection point.

[0080] Specifically, after the flue gas flows out of the semi-dry reactor and enters the bag dust removal device, ozone is sprayed into the waste gas treatment pipeline, and the ozone and the flue gas are mixed through the second gas-gas mixer at the injection point.

[0081] Specifically, after the flue gas flows out of the bag dust removal device and enters the SCR reactor, ozone is sprayed into the waste gas treatment pipeline, and the ozone and the flue gas are mixed through the third gas-gas mixer at the injection point.

[0082] In any of the above embodiments, the first branch or the second branch is selected according to the following rules:

[0083] When the required ozone amount is greater than the ozone output of the ozone delivery device, the second branch is turned on.

[0084] When the required ozone amount is less than the ozone output of the ozone delivery device, the first branch is turned on.

[0085] In this embodiment, the required ozone amount under the current boiler flue gas condition is first calculated according to the proportional function, and the value is compared with the real-time ozone production of the ozone delivery device under the current temperature and pressure conditions. If the calculation result shows that the required ozone amount exceeds the maximum continuous production of the ozone delivery device, i.e. there is a shortage of ozone supply, it is determined that the reduction capacity of the catalyst section is needed to compensate for the denitration deficit, so the switching valve arranged on the second branch is immediately opened, the flue gas passes through the SCR reactor along the original path, and then enters the absorption tower to complete the deep denitration. At this time, the first branch remains closed to avoid high concentration of nitrogen oxides without catalytic reaction directly entering the absorption tower, causing emission exceeding the standard. For example, when the waste incineration boiler is running at full load and accompanied by a sudden increase in fuel nitrogen content, the required ozone amount increases to forty standard cubic meters per hour, while the maximum production of a single ozone delivery device is only thirty-five standard cubic meters per hour. The system detects the shortage and turns on the second branch within two seconds, while maintaining the third gas-gas mixer in polishing mode to ensure that the nitrogen oxide concentration at the inlet of the SCR reactor is within the economic range of the catalyst.

[0086] If it is judged that the required ozone amount is lower than the ozone delivery device production threshold, it means that the ozone oxidation section has the ability to independently complete the denitration task, at this time the first branch is selected to be turned on, and the second branch switching valve is closed, so that the flue gas mixed by ozone in three stages directly enters the absorption tower. This not only avoids the deposition of ammonium bisulfate on the catalyst in the SCR reactor under low load or low temperature, but also saves the consumption of reducing agent. Taking the night low load condition as an example, the boiler evaporation capacity is reduced to fifty percent of the rated load, and the required ozone amount is calculated to be twenty-five standard cubic meters per hour, while the ozone delivery device can still provide thirty standard cubic meters at this temperature. The system determines that there is an excess of ozone, and automatically switches to the first branch bypass, and keeps the third gas-gas mixer at a low flow polishing mode to ensure that the nitrogen oxide at the end of the emission is controlled below forty-five milligrams per cubic meter.

[0087] Further, the denitration improvement method further comprises the following steps:

[0088] When the amount of nitrogen oxides at the end of the exhaust gas treatment pipeline is within the preset range, the controller adjusts the ozone input amount of each dosing point until the ozone production of the required ozone delivery device reaches the minimum value.

[0089] As can be seen from the above, the controller reads the end online nitrogen oxide concentration signal, and confirms that the concentration has been continuously stabilized in the preset range value of the sliding window; then the current ammonia injection amount and the flue gas flow parameter are frozen, and only the ozone injection amount is adjusted slightly. The controller reduces the pre-injection point flow valve opening by 5% according to the descending step strategy, and locks for 10 seconds to compare the change of the end nitrogen oxide concentration. If the concentration remains in the preset range value, the same injection point flow valve opening is continuously reduced until the end concentration shows an upward trend or approaches the upper threshold. At this time, the minimum stable flow value of the point is recorded, the above-mentioned action is repeated by switching to the middle injection point, and the three rounds of fine adjustment are completed by switching to the end injection point.

[0090] After completing a single round of fine adjustment, the controller calculates the sum of the flow of the three points and queries the current power of the ozone generation module. If the power is still higher than the recorded value of the last iteration, it means that there is remaining optimization space for one or more points, and the controller enters the second round of more fine step adjustment, reducing the flow valve opening by 2% each time, repeating the steady state verification process, until the total flow of the three points is reduced to the point where it cannot be reduced without causing the end concentration to exceed the limit.

[0091] As can be seen from the above, taking the fifty percent load of the waste incineration boiler at night as an example, the initial pre-injection, middle and end three-point ozone flow is twelve, eight and five standard cubic meters per hour respectively. After three iterations, the controller reduces the pre-injection flow to nine, the middle flow to six, and the end flow to four, the total power of the ozone generation module is reduced from 95% to 78%, and the end nitrogen oxide concentration remains around 45 mg / m3. Through the minimum power point alarm protection mechanism, a new benchmark is recorded, and if the subsequent furnace load changes, the optimization process is triggered again to ensure that the lowest ozone consumption is maintained to maintain stable emissions in different load intervals.

[0092] Specifically, the controller comprises:

[0093] The state and control vector module collects all real-time working condition information required for denitration decision on the left side of the state vector, including nitrogen oxides, acid gases, elemental mercury, temperature, flow and catalyst activity. The right side control vector is a three-way ozone flow instruction, and the algorithm adjusts the three injection points by solving the optimal trajectory:

[0094]

[0095] In the formula, is the current time; is the first gas-gas mixer ozone instantaneous volume flow of the pre-injection section; is the second gas-gas mixer ozone instantaneous volume flow of the middle section; is the third gas-gas mixer ozone instantaneous volume flow of the end section; is the state vector, describing the flue gas and the device operating state at time t; is the mass concentration of nitrogen monoxide; is the mass concentration of nitrogen dioxide; is the mass concentration of sulfur dioxide; is the volume fraction of gaseous elemental mercury in the flue gas; is the flue gas temperature; is the flue gas volume flow; is the control vector, specifying the three-way ozone injection flow at time t.

[0096] a strong nonlinear dynamic module for describing the instantaneous influence of ozone flow on the concentrations of various pollutants and catalyst activity; including: nitrogen monoxide is consumed and converted into nitrogen dioxide by the front and middle sections of ozone, while nitrogen dioxide can be further consumed by the end section of ozone; sulfur dioxide only has a sub-linear competitive reaction with ozone at the high-temperature front section; the high-order oxidation effect of elemental mercury in the middle section of the temperature control zone; high-dose ozone in the end section accelerates the decay of catalyst activity:

[0097]

[0098] wherein, is the time derivative of the state vector, describing the rate of change of each pollutant or parameter; is the kinetic constant of the reaction between nitrogen monoxide and ozone; is is the reaction constant consumed in the end section; is the sulfur dioxide oxidation reaction rate coefficient; is the mercury oxidation reaction constant; is the catalyst decay rate coefficient.

[0099] an optimal control objective module, including a first term that is the emission entropy, which sharply rises when NOx approaches the upper limit, and then three terms that are heterogeneous power consumption penalties: different exponents are used for different section flows, making the front section more sensitive to small flows and the incremental penalty for large flows stronger; the last term is a logarithmic barrier that ensures that the predicted emissions never cross the upper limit and provides a steep gradient drive, with the overall objective being to minimize ozone energy consumption while ensuring a safe margin for emissions:

[0100]

[0101] wherein, is the comprehensive performance index within the prediction window, with a smaller value indicating safer emissions and lower energy consumption; is the length of the rolling prediction window; is the upper limit of nitrogen oxide emissions set by regulations or processes; it is considered constant within the same window; is the ozone energy consumption penalty weight for the three sections, set according to the importance and cost difference of each section; For emission safety barrier weight, to adjust the sensitivity to the upper limit of the working condition.

[0102] The cooperative gradient flow solving module specifically includes:

[0103] The Hamiltonian function is used to combine the system dynamics and the instantaneous cost to generate the core quantity of the variational optimal condition; it captures the sensitivity of future emissions to the current control:

[0104]

[0105] In the formula, The Hamiltonian function is an instantaneous optimality evaluation function under the current state and control, used to derive the update direction of the control; The costate variable represents the sensitivity of future cost to the current state variable, and has the same dimension as the state; The state differential function is the dynamic model of the system , which describes the evolution of each state over time; The instantaneous loss function describes the current cost under the state and control, such as energy consumption, emission risk, etc.

[0106] The exponential gradient flow update unit is used to maintain the flow positive and asymptotically approach the physical upper limit in an exponential form; the gradient term comes from the partial derivative of the Hamiltonian with respect to the control quantity, and the step size is self-adjusted by the Armijo rule to ensure fast convergence and stability:

[0107]

[0108] In the formula, is the control quantity of the i-th ozone injection point at the k-th iteration; is the step size factor.

[0109] The branch switching and flexible valve control module specifically includes:

[0110] The catalyst attenuation index unit is used to represent that when decreases, the attenuation index increases, indicating the deterioration of the health of the SCR catalyst:

[0111]

[0112] In the formula, is the catalyst attenuation index, which represents the degree of degradation of the SCR catalyst, and the larger the index, the more attenuated it is; is the remaining activity of the catalyst over time.

[0113] The ozone saturation rate calculation unit is used to measure the proportion of the total flow of the current three-way ozone to the available production, reflecting the ozone surplus:

[0114]

[0115] wherein, is the time-varying ozone saturation rate; is the maximum gas production of the ozone generation system.

[0116] The flexible gating function unit maps the ozone excess and catalyst health to the interval 0 to 1 through double Sigmoid continuous mapping; when the ozone is close to saturation and the catalyst is healthy tends to 1, the system tends to pass through the SCR; when the ozone is in excess and the catalyst is attenuated tends to 0, the system tends to bypass the SCR:

[0117]

[0118] wherein, is the flexible control weight coefficient, the closer to 1, the more priority to enable the SCR; the closer to 0, the more the ozone system runs alone or is biased to bypass.

[0119] The predicted emission approximation module is used for the current three-way flow vector and the efficiency matrix E(t) to linearly estimate the NOx removal amount in a short time window; the approximation is used for real-time evaluation of the constraint and logarithmic barrier term:

[0120]

[0121] wherein, is the predicted time NOx emission concentration; is the current NOx concentration; is the removal efficiency coefficient; is the current ozone flow vector; is the three-way removal efficiency matrix; is a column vector.

[0122] The constraint condition module is used to ensure that a single way does not monopolize resources, the total ozone does not exceed the production limit, and at the same time ensures that the predicted emission stays within the regulatory boundary:

[0123]

[0124] wherein, is the actual injection flow rate of the i-th ozone injection point, indicating the ozone input amount at different arrangement positions.

[0125] Further, the controller further comprises:

[0126] The cooperative criterion module is used to automatically judge whether the SCR and the ozone section are simultaneously put into operation when the flue gas amount is too large, and the cooperative switching value can be obtained as long as the input is real-time:

[0127]

[0128] wherein, represents the ratio of current flue gas flow to rated flow; is the percentage of residual activity of SCR catalyst, 0 to 1; is valued from 0 to 1, and is used as the SCR operation coefficient.

[0129] When the flue gas flow exceeds the rated flow by more than 10%, both Sigmoids tend to 1, ≈1, the control system determines that cooperation is needed: ozone is added according to the conventional three-stage method, and the SCR ammonia injection is simultaneously started.

[0130] If the flow has not significantly increased or the catalyst has low activity, either Sigmoid output is close to 0, ≈0, the system only relies on three-stage ozone oxidation and bypasses the SCR.

[0131] Specifically, the proportional function includes:

[0132] Total ozone demand :

[0133]

[0134] wherein, is the baseline, is the influence coefficient of the corresponding item.

[0135] Three-stage addition weight:

[0136]

[0137] wherein, is the NO proportion factor.

[0138]

[0139] wherein, is the ozone addition weight of the pre-positioned addition point, is the ozone addition weight of the intermediate addition point, is the ozone addition weight of the terminal addition point, is the adjustment factor, used to adjust the sensitivity of the ozone addition weight of each stage under different working conditions.

[0140] The connection state representing the instantaneous flow of three-stage ozone:

[0141]

[0142] The application provides an improved denitration method based on ozone oxidation, which realizes step-by-step conversion of nitric oxide into high-valence nitrogen oxides by segmented ozone addition, significantly reduces the concentration of nitric oxide at the inlet of the SCR reactor, improves the subsequent denitration reaction rate, and greatly improves the overall denitration efficiency. After the front-end ozone oxidation reduces the nitric oxide, the demand for reducing agent of the SCR reactor decreases, the risk of ammonia escape is reduced, and the sticking failure of the bag-type dust removal device is simultaneously alleviated. The communication state between the multiple addition points and the ozone delivery device can be adjusted in real time according to a proportional function, which can quickly respond to the fluctuation of the concentration of nitrogen oxides in the waste incineration flue gas and keep the end emission within the preset range. The proportional function takes the amount of nitrogen oxides and the amount of ozone as inputs, realizes on-demand addition, avoids energy waste caused by excessive decomposition of ozone, and significantly reduces the operating cost. The oxidation process in the ozone reaction channel does not depend on high-temperature catalysts, avoids catalyst deactivation and replacement costs, has small modification engineering quantity, and is suitable for upgrading the existing post-furnace system. The pre-oxidation simultaneously destroys foul-smelling organic matter and oxidizes elemental mercury, which lays a foundation for subsequent simultaneous deodorization and mercury removal in the absorption section, and has outstanding integrated environmental protection benefits.

[0143] Embodiments of the second aspect of the application propose a device. In some embodiments of the application, as shown in Figure 6 the device comprises:

[0144] The exhaust gas treatment pipeline is used to purify the nitrogen oxides in the flue gas discharged from the boiler exhaust port and discharge to the outside.

[0145] The ozone delivery device is used to generate ozone required for purifying nitrogen oxides.

[0146] The addition point is used to introduce the generated ozone into the exhaust gas treatment pipeline and follow the flue gas flow in the ozone reaction channel.

[0147] The device provided by the application has the advantages of high denitration efficiency, low operating cost, strong environmental adaptability, convenient maintenance, etc.

[0148] Specifically, the inlet flue 1 is connected with the boiler exhaust port and is used to guide the high-temperature flue gas into the subsequent treatment channel. The flue gas first passes through the first online NOx concentration instrument 2, realizes real-time detection of nitric oxide, and provides the first set of reference data for the ozone addition proportional function. Then, the first gas-gas mixer 3 injects ozone in the highest temperature section of the flue gas, and quickly oxidizes part of the nitric oxide into high-valence nitrogen oxides.

[0149] Specifically, the oxidized flue gas enters the semi-dry reactor 4, reacts with calcium hydroxide dry powder to remove sulfur dioxide, hydrochloric acid and hydrogen fluoride, and forms calcium sulfite and calcium sulfate solid by-products. After the temperature of the flue gas is reduced, the second gas-gas mixer 5 supplements ozone again for deep oxidation of residual nitrogen monoxide and simultaneous oxidation of elemental mercury and malodorous molecules.

[0150] Specifically, the bag dust removal device 6 captures the solid by-products and oxidation particles at the outlet of the semi-dry reactor, reducing the dust content. The induced draft fan 7 is located at the outlet of the bag dust removal device to compensate for pressure loss and stabilize the negative pressure in the channel. The third gas-gas mixer 8 behind the induced draft fan serves as a polishing section, with a small flow of ozone added to suppress fluctuations and reduce the load on the catalytic section. The second online NOx concentration instrument 9 is installed downstream of the third gas-gas mixer for feedback of the nitrogen oxide concentration at the inlet of the SCR, forming a closed-loop control with a proportional function.

[0151] Specifically, the SCR reactor 10 introduces ammonia gas when the catalyst temperature is normal, reducing the remaining nitrogen oxides to nitrogen and water vapor through selective catalytic reduction; when the catalyst is deactivated or the temperature is insufficient, the system can switch to a bypass, allowing the flue gas to bypass the SCR reactor and directly enter the absorption tower 11. The absorption tower 11 is equipped with a circulating spray device 16, which measures the amount of spray lye with a flowmeter 15, and the pH value of the lye is monitored by an online pH meter 12 and balanced by supplementing lye pipeline 14 and liquid discharge pipeline 13. The tower completes the absorption and conversion of high-valence nitrogen oxides, oxidized mercury, and residual acidic components.

[0152] Specifically, the heater 17 is located at the outlet of the absorption tower to slightly reheat the saturated wet flue gas, avoiding the appearance of condensation white smoke at the top of the chimney 18. The final clean flue gas is discharged into the atmosphere through the chimney 18.

[0153] Specifically, the ozone delivery system is located in the lower left corner of the equipment, including an oxygen source 19, an ozone generation system 20, a cooling water system 21, a gas flowmeter 22, and an online ozone concentration instrument 23. The oxygen source 19 provides high-purity oxygen, which is metered by the gas flowmeter 22 before entering the ozone generation system 20; the ozone generation system 20 uses a plate discharge structure, and the cooling water system 21 provides circulating cooling to maintain the temperature of the discharge gap; the generated ozone concentration is monitored by the online ozone concentration instrument 23 before being distributed to three gas supply pipes, which are connected to the first gas-gas mixer 3, the second gas-gas mixer 5, and the third gas-gas mixer 8, respectively. The ozone flow of each path is adjusted by the central controller according to the online NOx concentration, flue gas flow, and SCR state, with a proportional function as the core.

[0154] From the above, the intake flue 1 to the absorption tower 11 forms a main treatment channel, three gas-gas mixers complete the ozone addition in sections, the semi-dry reactor 4 and the bag dust removal device 6 constitute a pre-acid removal and dust removal area, the SCR reactor 10 and the absorption tower 11 provide deep denitration and synergistic deodorization and mercury removal, and the ozone delivery device provides controllable oxidation power. Through multi-point ozone mixing, high-frequency real-time monitoring and proportional function closed-loop regulation, the equipment has the comprehensive advantages of high denitration efficiency, low energy consumption, long catalyst life, stable odor control and convenient maintenance, and can continuously maintain the nitrogen oxide emission concentration below 50 mg / m3 under the condition of multiple load fluctuations, meeting the requirements of waste incineration ultra-low emission and multi-pollutant synergistic control.

[0155] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0156] The above-described embodiments are only descriptions of the preferred modes of the present application and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A method for improving denitration based on ozone oxidation, characterized in that, The method comprises the following steps: An ozone reaction channel passing through an SCR reactor in the exhaust treatment pipeline is demarcated on the exhaust treatment pipeline to be modified; along the flow direction of flue gas inside the exhaust treatment pipeline, a dosing point is arranged on the ozone reaction channel before the SCR reactor, before a semi-dry method reactor in the exhaust treatment pipeline, and before a bag-type dust removal device in the exhaust treatment pipeline, respectively; The method comprises the following steps: Ozone is sprayed into the exhaust treatment pipeline after flue gas flows out of the bag-type dust removal device and before the flue gas enters the SCR reactor, and ozone and flue gas are mixed by a third gas-gas mixer at the dosing point; A gas inlet flue is connected to a boiler exhaust port and the exhaust treatment pipeline; the boiler is started and flue gas is introduced into the exhaust treatment pipeline through the gas inlet flue; the ozone delivery device is started and ozone is introduced into the exhaust treatment pipeline through the dosing point; The communication state of the dosing point and the ozone delivery device is adjusted, the amount of nitrogen oxides in the exhaust treatment pipeline and the amount of ozone introduced under each communication state are monitored, and a proportional function is constructed according to the amount of nitrogen oxides and the amount of ozone; 2. The denitration improvement method according to claim 1, characterized by, The flue gas generated by the current boiler is treated by the exhaust treatment pipeline through the proportional function, so that the amount of nitrogen oxides in the flue gas discharged at the end of the exhaust treatment pipeline is adjusted to be within a preset range.

3. The denitration improvement method according to claim 2, characterized by, The ozone reaction channel comprises a first branch connecting an absorption tower in the exhaust treatment pipeline from the dosing point and a second branch connecting the absorption tower from the dosing point through the SCR reactor. The step of treating the flue gas generated by the current boiler by the exhaust treatment pipeline through the proportional function comprises: The component content of flue gas in the gas inlet flue is obtained at each time; The component content of flue gas at the current time is calculated to obtain the required amount of ozone by the proportional function; 4. The denitration improvement method according to claim 3, characterized by, The amount of ozone introduced into each dosing point is configured according to the calculated amount of ozone, and one of the first branch and the second branch is selected to be turned on.

5. The denitration improvement method according to claim 3, characterized by, Ozone is sprayed into the exhaust treatment pipeline before flue gas enters the semi-dry method reactor, and ozone and flue gas are mixed by a first gas-gas mixer at the dosing point.

6. The denitration improvement method according to any one of claims 2 to 5, characterized by, Ozone is sprayed into the exhaust treatment pipeline after flue gas flows out of the semi-dry method reactor and before the flue gas enters the bag-type dust removal device, and ozone and flue gas are mixed by a second gas-gas mixer at the dosing point. The first branch or the second branch is selected according to the following rules: When the required amount of ozone is greater than the ozone production of the ozone delivery device, the second branch is turned on; 7. The denitration improvement method according to claim 6, characterized by, When the required amount of ozone is less than the ozone production of the ozone delivery device, the first branch is turned on. The method further comprises the following steps:

8. An apparatus for implementing the ozone oxidation-based denitration improvement method according to any one of claims 1 to 7, characterized by, When the amount of nitrogen oxides at the end of the exhaust treatment pipeline is within the preset range, the amount of ozone introduced into each dosing point is adjusted by the controller until the ozone production of the ozone delivery device is minimized. The method comprises: An exhaust treatment pipeline for purifying nitrogen oxides in flue gas discharged from a boiler exhaust port and discharging to the outside; An ozone delivery device for generating ozone required for purifying nitrogen oxides; A dosing point is provided for passing the generated ozone into the exhaust gas treatment line and following the flue gas flow in the ozone reaction channel.

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