Denitration improvement method and equipment based on ozone oxidation

Abstract

The invention belongs to the technical field of flue gas pollutant treatment, and particularly discloses a denitration improvement method and equipment based on ozonation, and the method comprises the following steps: delimiting an ozone reaction channel on a waste gas treatment pipeline to be transformed; defining a plurality of feeding points on the ozone reaction channel; starting the boiler to introduce flue gas into the waste gas treatment pipeline, and starting the ozone conveying device to introduce ozone into the waste gas treatment pipeline; adjusting the communication state of the feeding point and the ozone conveying device, and monitoring the amount of nitrogen oxide in the waste gas treatment pipeline and the amount of correspondingly introduced ozone in each communication state; constructing a proportional function according to the nitrogen oxide amount and the ozone amount; controlling a waste gas treatment pipeline to treat the current flue gas generated by the boiler through a proportional function; the system and the method have the following advantages: through a multi-point ozone dynamic addition and SCR flexible cooperation mechanism, integrated efficient control of denitration, deodorization and demercuration under the condition of low-temperature and high-humidity waste incineration flue gas is realized, the treatment efficiency is remarkably improved, and the energy consumption and the operation and maintenance cost are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas pollutant treatment, and in particular to an improved denitrification method and equipment based on ozone oxidation. Background Art

[0002] Currently, waste incineration power plants generally use the SNCR denitrification process, with some new projects employing the low-temperature SCR process. While the SNCR process is mature, it suffers from low denitrification efficiency, which can easily lead to boiler scaling, corrosion, and ammonia slip. SCR requires flue gas reheating to approximately 400°C, resulting in high energy consumption, catalyst deactivation, and high maintenance costs. With tightening NOx emission limits, existing technologies are inefficient and limited in layout under low-temperature, high-humidity flue gas conditions, making it difficult to achieve integrated denitrification, deodorization, and mercury removal.

[0003] Therefore, an improved denitrification method and equipment based on ozone oxidation are proposed to solve the above-mentioned problems. Summary of the Invention

[0004] The present invention aims to provide an improved denitrification method and equipment based on ozone oxidation, so as to solve or improve the above-mentioned technical problem of difficulty in achieving efficient integrated denitrification, deodorization and mercury removal under low-temperature flue gas.

[0005] In view of this, a first aspect of the present invention is to provide an improved denitrification method and equipment based on ozone oxidation.

[0006] A second aspect of the present invention is to provide an apparatus.

[0007] The first aspect of the present invention provides an improved denitrification method based on ozone oxidation, comprising the following steps: defining an ozone reaction channel passing through an SCR reactor in the exhaust gas treatment pipeline to be modified; defining a plurality of dosing points connected to an ozone delivery device in sequence on the ozone reaction channel along the flow direction of the flue gas inside the exhaust gas treatment pipeline; connecting the boiler exhaust port and the exhaust gas treatment pipeline through an air inlet flue; starting the boiler and introducing flue gas into the exhaust gas treatment pipeline through the air inlet flue, starting the ozone delivery device and introducing ozone into the exhaust gas treatment pipeline through the dosing points; adjusting the connectivity between the dosing points and the ozone delivery device, monitoring the amount of nitrogen oxides in the exhaust gas treatment pipeline and the corresponding amount of ozone introduced under each connectivity state; constructing a proportional function based on the amount of nitrogen oxides and the amount of ozone; and controlling the exhaust gas treatment pipeline to treat the flue gas currently generated by the boiler through the proportional function, so as to adjust the amount of nitrogen oxides in the flue gas discharged from the end of the exhaust gas treatment pipeline to within a preset range.

[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 sprayed 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 sprayed 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 sprayed 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] Compared with the prior art, the present application has the following beneficial effects: 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; 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; By monitoring the content of nitrogen oxides in the exhaust gas treatment pipeline in real time and constructing a proportional function, accurate ozone injection and dynamic regulation and control are realized, ozone consumption is reduced, economic efficiency is further improved, and the problems of high maintenance cost and short maintenance cycle caused by catalyst deactivation are solved; 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; The flexible switching mechanism of ozone and SCR path enables the service life of the SCR system to be prolonged, and the overall maintenance cost is reduced.

[0018] 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

[0019] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the accompanying drawings, in which: Figure 1 The method flowchart of the present application; Figure 2 The ozone segmented dosing control flowchart of the present application; Figure 3 The double-branch switching control flowchart of the present application; Figure 4 The minimum ozone consumption optimization flowchart of the present application; Figure 5 The abnormal condition handling flowchart of the present application; Figure 6 The device structure schematic diagram of the present application.

[0020] wherein, Figures 1-6 The correspondence between the reference signs and the component names is as follows: 1 intake 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

[0021] In order to make the above-mentioned objects, 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.

[0022] In the following description, a large number of 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 manners different from those described herein, therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.

[0023] Please refer to Figures 1-6 , the following describes an improved method and equipment for denitration based on ozone oxidation.

[0024] 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. SNCR process is simple and mature, but has problems such as low denitration efficiency, boiler scaling, water cooling wall corrosion, etc. While the low-temperature SCR process has low denitration efficiency, the reactor is usually arranged after the deacidification and bag-type dust collector, and 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 the waste incineration flue gas easily lead to deactivation of the low-temperature catalyst, and the cost of replacing the catalyst is very high, so the process design and operation management capability are required to be very high, resulting in very poor actual effect.

[0025] Ozone oxidation denitration deodorization and mercury removal process is a very promising and accelerating popularization of flue gas denitration deodorization and mercury removal process, which has unique advantages in low temperature flue gas denitration field. The reaction speed is fast, the denitration efficiency is high, the deodorization effect is good, the mercury removal rate is high, the system operation is safe, stable and without secondary pollution, and the synchronous denitration deodorization and mercury removal can be realized. There is no catalyst failure problem and ammonia escape problem, the system is equipped with an oxygen system, no flue gas reheating is needed, and no other consumption is needed except for electric energy and absorption of alkali liquor.

[0026] 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 low efficiency, ammonia escape, and site limitations 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 popularized based on its many advantages.

[0027] The oxidation process is the process of oxidizing NO in flue gas to nitrogen dioxide and other soluble nitrogen oxides by ozone. Since the decomposition rate of ozone itself is 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 be completely oxidized to nitrogen dioxide and dinitrogen pentoxide.

[0028] The basic principle of ozone advanced oxidation of flue gas multi-removal includes that a plurality of pollutants can be oxidized by the ozone advanced oxidation system at a lower temperature to become easily soluble products, such as sulfur trioxide, oxidized mercury and nitrogen dioxide, dinitrogen trioxide, and dinitrogen pentoxide, which are high-valence nitrogen oxides, and enter the washing tower for wet absorption.

[0029] In view of the above-mentioned problems, the first aspect of the embodiments of the present application proposes a denitration improvement method based on ozone oxidation. In some embodiments of the present application, as shown in Figures 1-5 The denitration improvement method includes the following steps: S101, an ozone reaction channel passing through the SCR reactor in the waste gas treatment pipeline is demarcated on the waste gas treatment pipeline to be transformed; a plurality of dosing points connected with the ozone delivery device are demarcated on the ozone reaction channel in sequence along the flow direction of the internal flue gas of the waste gas treatment pipeline.

[0030] Here, on the basis of the existing flue gas treatment system structure, a minimum interference type modification is carried out to introduce an ozone oxidation denitration module. The ozone reaction channel refers to the flue section before the flue gas enters the SCR reactor, especially including the section where the high-temperature flue gas still has oxidation activity, and the section where the flue gas flow is relatively stable and suitable for uniform mixing. By dividing multiple ozone dosing points in this channel, not only can the step-by-step reaction control be realized, 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.

[0031] The ozone oxidation channel is divided in the straight pipe section, elbow section or hot standby bypass section before the flue gas enters the front section of 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 three areas such as the pre-stage, middle stage and SCR front stage according to the flue gas flow direction; each dosing point is connected with 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 to promote instantaneous oxidation reaction.

[0032] As can be seen from the 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 divided into an ozone reaction channel, and three ozone dosing points are set at 10 m, 6 m and 2 m from the SCR; 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; 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; the third section serves as a polishing section to ensure that the NO content at the SCR inlet is below the set threshold. Not only does it realize the ordered integration and function arrangement of the ozone oxidation section in physical space, but also it lays a structural foundation for precise ozone ratio adjustment, dynamic response to pollutant load changes and improvement of NOx oxidation conversion rate in subsequent steps.

[0033] Specifically, the step of sequentially dividing multiple dosing points connected with ozone delivery devices on the ozone reaction channel includes: Along the flow direction, dosing points are set on the ozone reaction channel before the SCR reactor and the flue gas treatment pipeline, respectively before the semi-dry reactor and the bag dust removal device.

[0034] According to the above specific description, a plurality of dosing points connected with the ozone conveying device are sequentially demarcated on the ozone reaction channel. Specifically, the partitioned dosing points are arranged in sequence before the semi-dry reactor, before the bag-type dust collector, and before the SCR reactor along the flue gas flow direction, thereby constructing three independently controllable ozone dosing areas of front, middle, and end. The partitioned arrangement scheme first takes full advantage of the high-temperature zone characteristics at the inlet of the semi-dry reactor, and sets the first dosing point at this position, so that the nitrogen monoxide can be subjected to primary oxidation with ozone before being deacidified, thereby rapidly reducing the original nitrogen monoxide concentration and weakening the competition effect of sulfur dioxide on the subsequent oxidation path. Then, the second dosing point is set before the inlet of the bag-type dust collector, and ozone is added in the middle-temperature section to supplement the further conversion of the nitrogen monoxide that is not completely oxidized in the first section, oxidize the foul-smelling organic matter and elemental mercury, and timely capture the generated oxidation particles by the subsequent filtering unit to prevent the high-valence nitrogen oxides from re-escaping after being combined with dust. Finally, the third dosing point is set before the inlet of the SCR reactor for polishing-type addition of a small amount of ozone to ensure that the nitrogen oxides entering the catalytic section have been converted into high-valence forms with higher reactivity in a large proportion, thereby significantly reducing the demand for reducing agent and reducing the risk of ammonia escape.

[0035] 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 reactor and two meters away from the outlet of the bag-type dust collector, the first dosing point can be arranged one meter before the inlet of the semi-dry reactor, the second dosing point can be arranged one meter before the inlet of the bag-type dust collector, and the third dosing point can be arranged zero point five meters before the inlet of the SCR reactor. Each dosing point is connected 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, thereby forming a linkage reaction chain of segmented dosing, step-by-step oxidation, and dynamic control, and finally achieving the overall goal of low cost, high efficiency, and collaborative multi-pollutant control.

[0036] In any of the above embodiments, the ozone reaction channel includes a first branch connecting the absorption tower in the waste gas treatment pipeline from the dosing point and a second branch connecting the absorption tower from the dosing point via the SCR reactor.

[0037] In this embodiment, the ozone reaction channel is jointly constituted by the first branch and the second branch in the latter half of the structure. The first branch is branched from the dosing point, directly merges into the absorption tower in the waste gas treatment pipeline through an independent pipe section to form a bypass channel bypassing the SCR reactor, and the second branch passes through the SCR reactor along the original flue gas duct and then merges into the absorption tower after being combined with the first branch. The two branches are realized by a switching valve group for online start-stop and flow ratio adjustment.

[0038] The first branch functions 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, so as to maintain the continuous denitration, deodorization and mercury removal capacity without relying on the catalyst, and convert the high-valence nitrogen oxides into nitrate and nitrite in the absorption tower by using the lye, thereby avoiding yellow smoke emission. Meanwhile, the first branch can reduce the system pressure loss and fan energy consumption due to the shorter pipeline length and smaller flow resistance, and provide a rapid response channel when the instantaneous load fluctuates.

[0039] The second branch undertakes the catalytic reduction task under the conventional working condition. When the SCR reactor works normally and the catalyst is in the best activity interval, ozone is only added at the front end to reduce the concentration of nitric oxide, and the nitrogen dioxide and high-valence nitrogen oxides enter the SCR reactor and react with the appropriate ammonia to deeply reduce the residual nitrogen oxides into nitrogen and water vapor, so as to achieve efficient denitration and inhibit ammonia escape. The flue gas treated by the catalytic section is combined with the first branch and enters the absorption tower for end washing, further capturing the pollutants not completely converted.

[0040] The two branches determine the distribution ratio according to the online nitrogen oxide concentration, the SCR reactor inlet temperature, the catalyst pressure drop and the absorption tower pH value in actual operation. Specifically, when the catalyst activity decreases 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 as to maintain the stable and standard end emission, prolong the catalyst service life and reduce the ammonia consumption; for example, during 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 to the absorption tower through the first branch, so as to avoid the production of ammonium bisulfate deposition in the SCR reactor under low temperature conditions and cause the catalyst pore to be blocked. Through the double-branch structure, not only the flexible matching between the denitration process and the equipment state is realized, but also the ozone utilization rate is improved, the overall energy consumption and maintenance cost are reduced, and the nitrogen oxide emission concentration is always stably controlled within the preset range value under various complex working conditions.

[0041] S102, connecting the boiler flue gas outlet and the waste gas treatment pipeline through the inlet flue; starting the boiler and introducing the 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 point.

[0042] Here, by establishing a stable, continuous, controllable ozone oxidation reaction conditions, for the step-by-step conversion of nitrogen oxides to provide actual operating conditions. First, by the inlet flue gas boiler outlet and exhaust gas treatment pipeline between the sealed connection, so that the boiler combustion of flue gas can be in accordance with the established path stable flow into the subsequent denitration device. In the premise of ensuring the sealing and corrosion resistance, the inlet flue is preferably made of heat-resistant steel or alloy composite material, and a temperature 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 boiler thermal load, so as to ensure that the flue gas conveying process does not leak or stress damage.

[0043] After the boiler normal temperature rise, the flue gas is introduced into the exhaust gas treatment pipeline by the inlet flue, and the flue gas mainly contains nitrogen oxides, sulfur dioxide, soot 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 to introduce ozone for primary oxidation. At this time, by starting the ozone delivery device, the modular ozone generation system is operated according to the set process control module, and the generated ozone is delivered to the multiple dosing points arranged respectively via 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 flow rate, and forms an oxygen-rich region locally, promoting the rapid oxidation of nitrogen oxides, especially nitric oxide, to nitrogen dioxide and higher valence compounds.

[0044] As can be seen from the above, not only the original NO concentration is reduced at 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 stage of starting a waste incineration power plant, when the flue gas temperature is stable 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 conditions. The coordinated start of continuous flue gas conveying and quantitative ozone injection not only ensures the smooth progress of the nitrogen oxide oxidation reaction, but also lays a foundation for the preparation of reactants for the downstream device operation, and has good controllability, stability and actual operation adaptability.

[0045] S103, adjust the communication state of 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.

[0046] Here, by establishing a set of dynamic response mechanism, to accurately match the different flue gas composition conditions under the demand for ozone injection, to achieve the optimal reaction coupling relationship between nitrogen oxides and ozone. By adjusting the communication state between each injection point and the ozone delivery device, you can choose to open or close the specified point based on the current operating conditions, or adjust the ozone injection flow rate of each point. The purpose is to achieve multi-stage ozone quantitative injection strategy through partition control without affecting the stability of the main gas flow, thereby significantly improving the ozone utilization efficiency, reducing unnecessary energy consumption and reaction redundancy.

[0047] In actual operation, the working state of different injection 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 injection points and operate 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 injection 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 achieved by electromagnetic valves, variable frequency fans, flow regulating valves, etc., and is uniformly managed by the central controller.

[0048] In order to quantify the actual denitration contribution of ozone, the amount of ozone introduced under each communication state and the residual concentration of nitrogen oxides in the waste gas treatment pipeline 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. Ozone flow is obtained through gas mass flow meters and electronic control flow modules, and is automatically recorded into the system database. By comparing and analyzing the ozone injection amount and the NOx concentration reduction amplitude 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.

[0049] As can be seen from the above, if under a certain operating condition, the first injection point injects 10 standard cubic meters of ozone per hour, the second injection point injects 6 standard cubic meters, and the third point is not opened, the monitoring finds that the NOx concentration before SCR decreases from the initial 150 mg / m3 to 72 mg / m3, then the system automatically judges that the denitration efficiency of the current injection strategy is 52%, and calculates the amount of ozone required for unit NOx removal based on the cumulative data of the previous and subsequent time periods, 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 quantitative 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 ozone oxidation denitration strategy.

[0050] S104, control the flue 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 discharged by the flue gas treatment pipeline end to be within the preset range value.

[0051] Here, by establishing an ozone dosing closed-loop regulation mechanism based on feedback control, the emission concentration of nitrogen oxides in the flue gas finally discharged through the flue gas treatment pipeline is always maintained within the preset range value required by environmental protection specifications, for example, controlled to be no higher than fifty milligrams per cubic meter of ultra-low emission standard. To this end, the proportional function constructed in the previous step is used as the basis of the control strategy, and the required total amount of ozone 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 dosing point in real time.

[0052] After the proportional function is established, multi-dimensional parameter linkage adjustment can be performed according to the deduction results, 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 dosing 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 boiler load fluctuation causes the instantaneous concentration of flue gas NOx to rise, 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 dosing points to increase the reaction capacity to a level that meets the actual emission requirements.

[0053] In addition, during the stable operation stage of the system, the control strategy does not blindly pursue the lowest emission concentration, but prioritizes ozone dosing efficiency according to the target range. When the NOx concentration is already below fifty milligrams per cubic meter and approaches thirty milligrams per cubic meter, the system automatically evaluates whether the denitration gain generated by continued ozone dosing is greater than the energy cost. If it is found that the marginal benefit of ozone dosing is decreasing and below the cost threshold, the system automatically reduces the gas supply power or closes some points to achieve energy-saving operation.

[0054] As can be seen from the above, for a waste incineration boiler with a flue gas flow of two hundred and fifty thousand 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 fifty percent, thirty percent and twenty percent of the total dosage respectively. When the online NOx concentration detector detects that the pre-SCR concentration rises to one hundred and twenty milligrams per cubic meter, the proportional function increases the molar ratio to 1.3, and the first two points are preferentially scheduled, while the third point is compensated and polished according to the actual dosing result to ensure that the end NOx concentration stabilizes and falls below fifty milligrams per cubic meter. Subsequently, the proportional function coefficients are corrected according to the comparison of historical data results to achieve self-adaptive dynamic optimization. Not only can stable and standard emissions be achieved under varying operating conditions, but also the denitration efficiency can be optimized under the condition of minimum energy consumption, providing a technical guarantee for the widespread application of ozone oxidation technology in engineering.

[0055] Specifically, the step of controlling the exhaust gas treatment pipeline to treat the flue gas generated by the current boiler by a proportional function comprises: At each time, the component content of the flue gas in the intake flue is obtained.

[0056] The component content of the flue gas at the current time is calculated by a proportional function to obtain the required ozone amount.

[0057] According to the calculated ozone amount, the ozone input amount of each dosing point is configured, and one of the first branch and the second branch is selected to be conducted.

[0058] According to the above specific description, the component content of the flue gas in the intake flue is obtained in real time. At each time, a plurality of groups of online analyzers installed in the cross section of the intake flue synchronously 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 the 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 time is generated, which is used as the input reference of the proportional function. By comparing the vectors of consecutive time periods, the change trend of the flue gas load can be further obtained to provide a reference for subsequent prediction and adjustment.

[0059] The required ozone amount corresponding to the component content of the flue gas at the current time is calculated by a proportional function. The proportional function is derived from the mapping relationship between the concentration of nitrogen oxides and the ozone injection amount established in step S103. The central control unit substitutes the above flue gas composition vector into the proportional function, and outputs the theoretical total ozone demand amount through linear interpolation or polynomial regression algorithm. In order to consider the denitration efficiency and energy consumption cost, the total ozone amount is also weighted and corrected according to the sulfur dioxide concentration, 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.

[0060] According to the calculation results, the ozone input amount of each dosing point is configured respectively, 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 three dosing points according to the preset segmentation coefficient, and the distribution ratio of each segment is corrected in real time combined with the online nitrogen oxide concentration feedback. After distribution is completed, the instruction is issued to adjust the variable frequency power of each ozone generation module, and at the same time 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 two percent. Subsequently, according to the SCR reactor inlet temperature, catalyst pressure drop and 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.

[0061] As can be seen from the above, taking full load operation of the 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 by the proportional function to be 35 Nm3 / h, and the target ozone amount is obtained after optimization and correction to be 32 Nm3. Among them, 50% is allocated to the front dosing point, 30% is allocated to the middle dosing point, and 20% is allocated to the end dosing 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%, so the second branch is maintained to be conducted. If the catalyst bed temperature is detected to be reduced to 220°C and the nitrogen oxide outlet concentration is increased to 75 mg / m3 after four hours of operation, the second branch is immediately closed and the first branch is conducted, the front dosing point ozone flow is adjusted to 20 Nm3 / h, and the middle and end dosing point flows are adjusted to 8 and 4 Nm3 / h respectively, so as to ensure that the end emission nitrogen oxide concentration is stably reduced to 45 mg / m3.

[0062] Specifically, before the flue gas enters the semi-dry reactor, ozone is sprayed on the waste gas treatment pipeline, and ozone and flue gas are mixed through the first gas-gas mixer at the dosing point.

[0063] Specifically, after the flue gas flows out of the semi-dry reactor and enters the bag dust removal device, ozone is sprayed on the waste gas treatment pipeline, and ozone and flue gas are mixed through the second gas-gas mixer at the dosing point.

[0064] Specifically, after the flue gas flows out of the bag filter and before entering the SCR reactor, ozone is injected into the waste gas treatment pipeline, and the ozone is mixed with the flue gas through a third gas-gas mixer at a point.

[0065] In any of the above embodiments, 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.

[0066] When the required amount of ozone is less than the ozone production of the ozone delivery device, the first branch is turned on.

[0067] In this embodiment, first, the required amount of ozone under the current boiler flue gas working condition is calculated according to a 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 amount of ozone 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 difference in denitrification, so the switching valve provided 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 denitrification. At this time, the first branch remains closed to avoid high-concentration nitrogen oxides without catalytic reaction directly entering the absorption tower, causing emission to exceed 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 amount of ozone 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.

[0068] If it is determined that the required amount of ozone is below the ozone production threshold of the ozone delivery device, it means that the ozone oxidation section has the ability to independently complete the denitrification 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 with ozone 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. For example, under the condition of low load at night, the boiler evaporation capacity is reduced to fifty percent of the rated load, and the required amount of ozone 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 emission at the end is controlled below forty-five milligrams per cubic meter.

[0069] Further, the denitrification improvement method further comprises the following steps: When the amount of nitrogen oxides at the end of the exhaust gas treatment pipeline is within the preset range, the controller adjusts the amount of ozone introduced at each dosing point until the ozone output of the required ozone delivery device reaches a minimum value.

[0070] 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 within the preset range value in the sliding window; then the current ammonia injection amount and flue gas flow parameters are frozen, and only the ozone injection amount is adjusted slightly. The controller reduces the pre-dosing point flow valve opening by 5% according to the descending step strategy, and locks it for 10 seconds before comparing the change in the end nitrogen oxide concentration. If the concentration remains within the preset range, the same dosing point flow valve opening continues to decrease until the end concentration shows an upward trend or approaches the upper threshold. At this time, record the minimum stable flow value of this point, switch to the middle dosing point and repeat the above actions, and then switch to the end dosing point to complete three rounds of fine tuning.

[0071] After completing a single round of fine tuning, the controller calculates the sum of the flow rates 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 still optimization space for one or more points, and the controller enters the second round of fine tuning with a smaller step size. Each time the flow valve opening is reduced by 2%, and the steady-state verification process is repeated 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.

[0072] As can be seen from the above, taking the fifty percent night load of the waste incineration boiler as an example, the initial pre-dosing, middle dosing and end dosing ozone flow rates are twelve, eight and five standard cubic meters per hour respectively. After three iterations, the controller reduces the pre-dosing flow rate to nine, the middle dosing flow rate to six, and the end dosing flow rate 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 baseline is recorded. 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 within the standard range at different load intervals.

[0073] Specifically, the controller comprises: The state and control vector module collects all real-time working condition information required for denitration decision-making on the left side of the state vector, including nitrogen oxides, acid gases, elemental mercury, temperature, flow rate and catalyst activity. The right side control vector is a three-way ozone flow rate instruction, and the algorithm adjusts the three dosing points by solving its optimal trajectory: In the formula, is the current time; is the first gas-gas mixer ozone instantaneous volume flow rate of the pre-dosing section; is the second gas-gas mixer ozone instantaneous volume flow rate of the middle dosing section; Ozone instantaneous volume flow rate for the third gas mixer at the end; X(t) is the state vector, describing the flue gas and the device operating state at time t; NO is the mass concentration of nitric oxide; NO2 is the mass concentration of nitrogen dioxide; SO2 is the mass concentration of sulfur dioxide; Hg0 is the volume fraction of gaseous elemental mercury in the flue gas; T is the flue gas temperature; V is the flue gas volume flow rate; U(t) is the control vector, specifying the three-way ozone injection flow rate at time t.

[0074] The strong nonlinear dynamic module is used to describe the instantaneous influence of ozone flow rate on the concentrations of various pollutants and catalyst activity; it includes: nitric oxide 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 undergoes sub-linear competitive reaction with ozone at high temperature in the front section; high-order oxidation effect of elemental mercury in the temperature control zone of the middle section; high-dose ozone in the end section accelerates the decay of catalyst activity: In the formula, dx / dt is the time derivative of the state vector, describing the change rate of each pollutant or parameter; kNO is the kinetic constant of the reaction between nitric oxide and ozone; kNO2 is kNO2 is the reaction constant consumed in the end section; kSO2 is the oxidation reaction rate coefficient of sulfur dioxide; kHg is the mercury oxidation reaction constant; kcat is the catalyst decay rate coefficient.

[0075] The optimal control objective module includes the first term, which is the emission entropy, and its gain to the objective function increases sharply when NOx approaches the upper limit, and then the three terms are the heterogeneous power consumption penalties: different exponents are used for different section flow rates, making the front section more sensitive to small flow rates and the incremental penalty of large flow rates stronger; the last term is the logarithmic barrier, which ensures that the predicted emissions never cross the upper limit and provides a steep gradient drive, and the overall objective is to minimize ozone energy consumption while ensuring a safe margin of emissions: In the formula, J(t) is the comprehensive performance index within the prediction window, and the smaller the value, the safer the emissions and the lower the energy consumption; N is the length of the rolling prediction window; NOx is the upper limit of nitrogen oxide emissions set by regulations or processes; it is considered constant within the same window; W is the ozone energy consumption penalty weight for the three sections, which is set according to the importance and cost difference of each section; The emission safety barrier weight is used to adjust the sensitivity to the upper limit working condition.

[0076] The cooperative gradient flow solving module specifically comprises: The Hamilton function is used to combine the system dynamics and the instantaneous cost to generate the core quantity of the variational optimal condition; and the Hamilton function is used to capture the sensitivity of future emissions to current control: In the formula, The Hamilton function is an instantaneous optimality evaluation function under the current state and control, and is used to derive the update direction of the control; The costate variable represents the sensitivity of the 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.

[0077] The exponential gradient flow update unit is used to maintain the flow positive by an exponential form and asymptotically approach the physical upper limit; the gradient term comes from the partial derivative of the Hamilton with respect to the control quantity, and the step size is self-adjusted by the Armijo rule to ensure fast convergence and stability: In the formula, The control quantity of the i-th ozone injection point at the k-th iteration is The step size factor is

[0078] The branch switching and flexible valve control module specifically comprises: The catalyst attenuation index unit is used to represent that when The attenuation index rises, indicating the deterioration of the health of the SCR catalyst: In the formula, The catalyst attenuation index represents the degree of degradation of the SCR catalyst, and the greater the index, the more attenuated the catalyst is; The remaining activity of the catalyst changes over time.

[0079] 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, and reflects the ozone surplus: In the formula, The ozone saturation rate changes over time; The maximum gas production of the ozone generation system is

[0080] A flexible gating function unit maps the ozone excess and catalyst health to the interval 0 to 1 through a double sigmoid function; when ozone is close to saturation and catalyst is healthy tends to 1, the system tends to pass through the SCR; when ozone is in excess and catalyst is degraded tends to 0, the system tends to bypass the SCR: wherein, is a 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 tends to bypass.

[0081] A predicted emission approximation module is used for the current three-way flow vector to linearly estimate the NOx removal amount in a short time window; the approximation is used for real-time evaluation of constraints and logarithmic barrier terms: wherein, is the predicted time of the NOx emission concentration; is the NOx concentration at the current time; is the removal efficiency coefficient; is the current ozone flow vector; is the three-way removal efficiency matrix; is a column vector.

[0082] A 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 the predicted emission stays within the regulatory boundary: wherein, is the actual injection flow rate of the i-th ozone injection point, indicating the ozone input at different arrangement positions.

[0083] Further, the controller further comprises: A coordination criterion module is used to automatically determine whether the SCR and the ozone section are simultaneously put into operation when the flue gas amount is too large, and the coordination switching value can be obtained as long as the input is real-time: wherein, , indicates the ratio of the current flue gas amount to the rated flow; is the percentage of the remaining activity of the SCR catalyst, 0 to 1; is valued at 0 to 1 and is used as an SCR operation coefficient.

[0084] When the flue gas amount exceeds the rated one by more than 10%, the two sigmoids simultaneously tend to 1, ≈1, control system determines that coordination is required: ozone is added in the conventional three-stage mode, and the SCR is simultaneously opened for ammonia injection.

[0085] If the flow rate does not increase significantly or the catalyst is low in activity, either Sigmoid output approaches 0, ≈0, the system relies only on three-stage ozone oxidation and bypasses the SCR.

[0086] Specifically, the proportional function includes: Total ozone requirement : wherein, is the baseline, is the influence coefficient of the corresponding item.

[0087] Three-stage addition weight: wherein, is the NO proportion factor.

[0088] wherein, is the ozone addition weight of the pre-positioned point, is the ozone addition weight of the intermediate position, is the ozone addition weight of the terminal position, is the adjustment factor, used to adjust the sensitivity of the ozone addition weight of each stage under different working conditions.

[0089] The connection state representing the instantaneous flow rate of three-stage ozone: 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 amount of nitric oxide, the demand for reducing agent in 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 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 nitrogen oxide concentration in the waste incineration flue gas and keep the end-of-pipe 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 operating costs. The oxidation process in the ozone reaction channel does not depend on high-temperature catalysts, avoiding catalyst deactivation and replacement costs, with small modification engineering quantity and being suitable for upgrading the existing post-furnace system. The pre-oxidation simultaneously destroys foul-smelling organic matter and oxidizes elemental mercury, laying the foundation for subsequent simultaneous deodorization and mercury removal in the absorption section, and achieving outstanding integrated environmental benefits.

[0090] 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: An exhaust gas treatment pipeline for purifying nitrogen oxides in flue gas discharged from a boiler exhaust port and discharging to the outside.

[0091] An ozone delivery device for generating ozone required for purifying nitrogen oxides.

[0092] An addition point for introducing the generated ozone into the exhaust gas treatment pipeline and following the flue gas flow in the ozone reaction channel.

[0093] The device provided by the application has the advantages of high denitration efficiency, low operating cost, strong environmental adaptability, and convenient maintenance.

[0094] Specifically, the inlet flue 1 is connected to the boiler exhaust port for guiding high-temperature flue gas into the subsequent treatment channel. The flue gas first passes through the first online NOx concentration instrument 2 to realize real-time detection of nitric oxide, providing 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, rapidly oxidizing part of the nitric oxide into high-valence nitrogen oxides.

[0095] Specifically, the oxidized flue gas enters the semi-dry reactor 4, where it reacts with calcium hydroxide powder to remove sulfur dioxide, hydrochloric acid, and hydrogen fluoride, forming calcium sulfite and calcium sulfate as solid byproducts. After the flue gas temperature drops, ozone is added to the second gas-gas mixer 5 to deeply oxidize residual nitric oxide and simultaneously oxidize elemental mercury and odor molecules.

[0096] Specifically, a bag filter 6 captures solid byproducts and oxidized particles at the outlet of the semi-dry reactor, reducing dust levels. An induced draft fan 7, located at the outlet of the bag filter, compensates for pressure drop and stabilizes negative pressure in the channel. A third gas-to-gas mixer 8, located behind the induced draft fan, serves as a polishing stage. Ozone is added at a low flow rate to suppress fluctuations and reduce the load on the catalytic stage. A second online NOx concentration meter 9, installed downstream of the third gas-to-gas mixer, provides feedback on the nitrogen oxide concentration at the SCR inlet, forming a closed-loop control loop with the proportional function.

[0097] Specifically, when the catalyst temperature is normal, ammonia is introduced into the SCR reactor 10, 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 switches to a bypass mode, allowing the flue gas to bypass the SCR reactor and enter the absorption tower 11 directly. The absorption tower 11 is equipped with a circulating spray device 16, with the amount of alkali solution sprayed being measured by a flow meter 15. The pH value of the alkali solution is monitored by an online pH meter 12 and maintained in equilibrium with the drain pipe 13 through the alkali solution replenishment pipe 14. This tower completes the absorption and conversion of high-valent nitrogen oxides, mercuric oxide, and residual acidic components.

[0098] Specifically, the heater 17 is located at the outlet of the absorption tower and is used to slightly reheat the saturated wet flue gas to avoid the condensation of white smoke at the top of the chimney 18. Finally, the clean flue gas is discharged into the atmosphere through the chimney 18.

[0099] Specifically, the ozone delivery system, located in the lower left corner of the equipment, comprises an oxygen source 19, an ozone generation system 20, a cooling water system 21, a gas flowmeter 22, and an online ozone concentration meter 23. The oxygen source 19 provides high-purity oxygen, which is metered by the gas flowmeter 22 and then enters the ozone generation system 20. The ozone generation system 20 utilizes a plate-type discharge structure, and the cooling water system 21 provides circulating cooling to maintain the discharge gap temperature. The generated ozone concentration is monitored by the online ozone concentration meter 23 and then distributed to three gas supply pipes, connecting to the first gas-gas mixer 3, the second gas-gas mixer 5, and the third gas-gas mixer 8, respectively. The ozone flow rates of each pipe are regulated by a central controller, dynamically adjusted based on the online NOx concentration, flue gas flow rate, and SCR status, using a proportional function as the core.

[0100] 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.

[0101] 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.

[0102] 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. An improved denitrification method based on ozone oxidation, characterized in that: The steps include: An ozone reaction channel is defined on the exhaust gas treatment pipeline to be modified, passing through an SCR reactor in the exhaust gas treatment pipeline; and multiple dosing points connected to an ozone delivery device are sequentially defined on the ozone reaction channel along a flow direction of flue gas inside the exhaust gas treatment pipeline; connecting the boiler exhaust port and the exhaust gas treatment pipeline through the air inlet flue; starting the boiler and introducing flue gas into the exhaust gas treatment pipeline through the air inlet flue, starting the ozone delivery device and introducing ozone into the exhaust gas treatment pipeline through the dosing point; Adjusting the connection state between the dosing point and the ozone delivery device, monitoring the amount of nitrogen oxides in the exhaust gas treatment pipeline and the corresponding amount of ozone introduced in each connection state; and constructing a proportional function based on the amount of nitrogen oxides and the amount of ozone; The exhaust gas treatment pipeline is controlled by the proportional function to treat the flue gas generated by the current boiler, so as to adjust the amount of nitrogen oxides discharged from the flue gas at the end of the exhaust gas treatment pipeline to within a preset range.

2. The improved denitrification method according to claim 1, characterized in that: The step of sequentially defining a plurality of dosing points connected to the ozone delivery device on the ozone reaction channel includes: Along the flow direction, the dosing points are set on the ozone reaction channel respectively before the SCR reactor and the semi-dry reactor and the bag dust collector in the exhaust gas treatment pipeline.

3. The improved denitrification method according to claim 2, characterized in that: The ozone reaction channel includes a first branch connected from the dosing point to the absorption tower in the exhaust gas treatment pipeline and a second branch connected from the dosing point to the absorption tower via the SCR reactor.

4. The improved denitrification method according to claim 3, characterized in that: The step of controlling the exhaust gas treatment pipeline to treat the flue gas currently generated by the boiler through the proportional function includes: Obtaining the component content of the flue gas in the intake flue at each moment; Calculate the required ozone amount corresponding to the component content of the flue gas at the current moment through the proportional function; The ozone input amount of each dosing point is configured according to the calculated ozone amount, and one of the first branch and the second branch is selected for connection.

5. The improved denitrification method according to claim 4, characterized in that: Before the flue gas enters the semi-dry reactor, ozone is sprayed into the exhaust gas treatment pipeline, and the ozone and the flue gas are mixed through the first gas-gas mixer at the dosing point.

6. The improved denitrification method according to claim 4, characterized in that: After the flue gas flows out of the semi-dry reactor and before it enters the bag dust removal device, ozone is sprayed into the exhaust gas treatment pipeline, and the ozone and flue gas are mixed through the second gas-gas mixer at the dosing point.

7. The improved denitrification method according to claim 6, characterized in that: After the flue gas flows out of the bag dust removal device and before entering the SCR reactor, ozone is sprayed into the exhaust gas treatment pipeline, and the ozone and flue gas are mixed through the third gas-gas mixer at the dosing point.

8. The improved denitration method according to any one of claims 3 to 7, characterized in that: 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 output of the ozone delivery device, the second branch is opened; When the required amount of ozone is less than the ozone output of the ozone delivery device, the first branch is opened.

9. The improved denitrification method according to claim 8, characterized in that: The following steps are also included: When the amount of nitrogen oxides at the end of the exhaust gas treatment pipeline is within the preset range, the ozone injection amount at each of the dosing points is adjusted by the controller until the ozone production of the required ozone delivery device reaches the minimum value.

10. An apparatus for implementing the improved denitrification method based on ozone oxidation according to any one of claims 1 to 9, characterized in that: include: The exhaust gas treatment pipeline is used to purify the nitrogen oxides in the flue gas discharged from the boiler exhaust port and discharge it to the outside; Ozone delivery device, used to generate ozone required for purifying nitrogen oxides; The dosing point is used to pass the generated ozone into the exhaust gas treatment pipeline and flow along with the flue gas in the ozone reaction channel.

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