SCR (Selective Catalytic Reduction) denitration system adaptive to boiler working condition change

Abstract

The utility model discloses an SCR (Selective Catalytic Reduction) denitration system suitable for the working condition change of a boiler, which comprises an SCR denitration reactor, a rectification grid is arranged in the SCR denitration reactor, and a vanadium-titanium catalyst is arranged at one end of the rectification grid; an SCR inlet flue is arranged at one end of the SCR denitration reactor, an SCR inlet flue regulating valve is arranged on the SCR inlet flue, an ammonia spraying grid is arranged at one end of the SCR inlet flue regulating valve, and the SCR inlet flue is connected with the inlet end of the SCR denitration reactor; and a low-temperature flue gas bypass and a high-temperature flue gas bypass are arranged at one end of the SCR inlet flue. The device can be suitable for the working condition change of the boiler, and when the boiler is frequently subjected to high-load or low-load peak regulation, it is guaranteed that the inlet smoke temperature of the SCR denitration reactor is always kept in a stable range.

Description

Technical Field

[0001] This utility model belongs to the field of flue gas treatment technology, specifically relating to an SCR denitrification system adapted to changes in boiler operating conditions. Background Technology

[0002] The statements in this section are merely background information related to this utility model and do not necessarily constitute prior art.

[0003] Nitrogen oxides (NOx) are easily affected by acid rain and photochemical smog, which can damage the ozone layer and pose serious threats to the environment and human health. In recent years, total NOx emissions have remained high, with coal-fired power plants being the largest emitter. Statistics show that 60% of NOx emissions come from coal combustion, with coal-fired power plants accounting for 70% of this consumption. Therefore, boilers in coal-fired power plants must adopt denitrification systems to comprehensively address and control NOx emissions.

[0004] Currently, commonly used denitrification processes include selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR), as well as SNCR / SCR combined flue gas denitrification technology developed based on these two. However, the most widely used is the SCR (selective catalytic reduction) denitrification process. SCR technology is used for NOx control in power plant boilers. Its principle is to inject ammonia gas, a reducing agent, into the flue gas duct downstream of the boiler at 320℃~400℃. Under the action of a catalyst, NOx in the flue gas is reduced to harmless N2 and H2O.

[0005] The inventors discovered that the most critical factor in the SCR denitrification process is the catalytic temperature of the catalyst. Currently, the catalytic temperature of commonly used SCR catalysts in boilers is generally between 320℃ and 400℃. Due to production needs, industrial boiler operating conditions are very complex, and boiler load fluctuates frequently, adjusting back and forth between 30% and 110% under BMCR conditions. This can lead to the flue gas temperature entering the SCR reactor being too low or too high within this range. In addition to reducing the SCR denitrification efficiency, this can also lead to an increase in ammonia slip, thereby affecting the company's environmental emission indicators and causing unnecessary losses to the company. Utility Model Content

[0006] To address the aforementioned issues, this invention provides an SCR denitrification system adapted to changes in boiler operating conditions. This system is suitable for varying boiler operating conditions and ensures that the inlet flue gas temperature of the SCR denitrification reactor remains within a stable range when the boiler is frequently operating at high or low loads.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] An SCR denitrification system adapted to changes in boiler operating conditions includes an SCR denitrification reactor. A rectifier grid is installed inside the SCR denitrification reactor, and a vanadium-titanium catalyst is installed at one end of the rectifier grid. One end of the SCR denitrification reactor is an SCR inlet flue, and an SCR inlet flue regulating valve is installed on the SCR inlet flue. An ammonia injection grid is installed at one end of the SCR inlet flue, and the SCR inlet flue is connected to the inlet end of the SCR denitrification reactor. A low-temperature flue gas bypass and a high-temperature flue gas bypass are provided at one end of the SCR inlet flue.

[0009] Furthermore, the low-temperature flue gas bypass is connected to the SCR inlet flue, and a low-temperature flue gas bypass regulating valve is installed on the low-temperature flue gas bypass.

[0010] Furthermore, the high-temperature flue gas bypass is connected to the SCR inlet flue, and a high-temperature flue gas bypass regulating valve is installed on the high-temperature flue gas bypass.

[0011] Furthermore, the vanadium-titanium catalyst is provided with multiple layers spaced apart, and an acoustic soot blower is arranged on the upper surface of the vanadium-titanium catalyst.

[0012] Furthermore, several sonic soot blowers are provided, and one end of each sonic soot blower is connected to a compressed air tank.

[0013] Furthermore, several ammonia injection grilles are spaced apart, and the ammonia injection grilles are connected to ammonia gas pipelines.

[0014] Furthermore, the other end of the SCR denitrification reactor is an SCR outlet flue, which is connected to the outlet end of the SCR denitrification reactor.

[0015] Furthermore, an SCR outlet flue regulating valve is installed on the SCR outlet flue, and an SCR flue gas bypass is provided at one end of the SCR outlet flue.

[0016] Furthermore, one end of the SCR flue gas bypass is connected to the SCR inlet flue, and the other end of the SCR flue gas bypass is connected to the SCR outlet flue. An SCR flue gas bypass regulating valve is installed on the SCR flue gas bypass.

[0017] Furthermore, an electric hoist for maintenance and lifting is installed at one end of the SCR denitrification reactor.

[0018] Compared with the prior art, the advantages and positive effects of this utility model are:

[0019] This invention features an SCR denitrification reactor with an SCR inlet flue and an SCR outlet flue at both ends. A high-temperature flue gas bypass and a low-temperature flue gas bypass are also located at one end of the reactor. When the boiler load is low, causing the SCR inlet flue gas temperature to drop below 320°C, the high-temperature flue gas bypass is used to adjust the temperature and prevent catalyst deactivation. Conversely, when the boiler load is high, causing the SCR inlet flue gas temperature to exceed 400°C, the low-temperature flue gas bypass is used to adjust the temperature and prevent catalyst sintering. In other words, when the boiler load fluctuates between 30% and 110%, the SCR inlet flue gas temperature can be consistently maintained between 320°C and 400°C, ensuring catalyst reactivity, meeting denitrification efficiency requirements, reducing ammonia slip, and extending the catalyst's chemical lifespan.

[0020] This invention features an SCR flue gas bypass. When the SCR denitrification reactor needs to be inspected, maintained, or have its catalyst replaced, the SCR reactor can be isolated via the SCR flue gas bypass, allowing for offline replacement of the SCR catalyst without affecting boiler shutdown. Attached Figure Description

[0021] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.

[0022] Figure 1 This is a structural diagram of the SCR denitrification system of this utility model;

[0023] In the diagram: 1. SCR denitrification reactor; 2. Vanadium-titanium catalyst; 3. Acoustic soot blower; 4. Ammonia injection grid; 5. Low-temperature flue gas bypass; 6. Low-temperature flue gas bypass regulating valve; 7. High-temperature flue gas bypass; 8. High-temperature flue gas bypass regulating valve; 9. SCR flue gas bypass; 10. SCR flue gas bypass regulating valve; 11. SCR inlet flue; 12. SCR inlet flue regulating valve; 13. SCR outlet flue; 14. SCR outlet flue regulating valve; 15. Maintenance lifting electric hoist; 16. Rectifying grid. Detailed Implementation

[0024] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0025] The most critical factor in the SCR denitrification process is the catalytic temperature of the catalyst. Currently, the catalytic temperature of commonly used SCR catalysts in boilers is generally between 320℃ and 400℃. Due to production needs, the operating conditions of industrial boilers are very complex, and the boiler load fluctuates frequently, adjusting back and forth between 30% and 110% under BMCR conditions. This can lead to the flue gas temperature entering the SCR reactor being too low or too high within this range. In addition to reducing the SCR denitrification efficiency, this can also lead to an increase in ammonia slip, thereby affecting the company's environmental emission indicators and causing unnecessary losses to the company.

[0026] The present invention will now be described in detail with reference to the accompanying drawings. This embodiment discloses an SCR denitrification system adapted to changes in boiler operating conditions, such as... Figure 1 As shown, the reactor includes an SCR denitrification reactor 1, a rectifier grid 16 is arranged inside the SCR denitrification reactor 1, and a vanadium-titanium catalyst 2 is arranged at one end of the rectifier grid 16; one end of the SCR denitrification reactor 1 is an SCR inlet flue 11, an SCR inlet flue regulating valve 12 is installed on the SCR inlet flue 11, an ammonia injection grid 4 is installed at one end of the SCR inlet flue regulating valve 12, and the SCR inlet flue 11 is connected to the inlet end of the SCR denitrification reactor 1; a low-temperature flue gas bypass 5 and a high-temperature flue gas bypass 7 are provided at one end of the SCR inlet flue 11.

[0027] The SCR denitrification reactor 1 is a vertical welded steel structure vessel, internally equipped with a supporting structure for the vanadium-titanium catalyst 2 and the rectifying grid 16, capable of withstanding internal pressure, seismic load, flue gas load, catalyst load, and thermal stress. The reactor shell has reinforcing ribs and an insulation layer. The vanadium-titanium catalyst 2 is hoisted from 0 meters to the inlet of the catalyst installation door outside the reactor using an electric hoist 15; it is then inserted through the side door via the catalyst installation door inlet.

[0028] The SCR reactor includes: an SCR denitrification reactor body, a vanadium-titanium catalyst 2 (adapted temperature range 320℃~400℃), a catalyst maintenance and installation door, a catalyst maintenance manhole, a rectifier grid 16, and inlet and outlet flue gas damper doors. The catalyst maintenance and installation door is a 1300*1800 rectangular door used for loading and unloading catalysts. It is installed on the outside of each catalyst reactor wall panel. The number of maintenance doors required corresponds to the number of catalyst layers. Similarly, the maintenance manhole is installed on the outside of each catalyst reactor wall panel. The number of manholes required corresponds to the number of catalyst layers.

[0029] The reaction between ammonia and nitrogen oxides takes place within a catalyst, which is typically arranged in a vertically downward-facing reactor. The flue gas velocity is controlled at approximately 4–6 m / s. Therefore, a large-scale SCR denitrification reactor 1 is added. To fully utilize the residual activity of each catalyst layer and maximize the use of existing catalyst activity, an "X+1" catalyst arrangement is usually adopted, with X layers initially loaded and one layer reserved. The reactor is a vertical welded steel structure vessel with an internal catalyst support structure, capable of withstanding internal pressure, seismic loads, flue gas loads, catalyst loads, and thermal stress.

[0030] Each reactor layer needs to be equipped with a catalyst loading and unloading door, with a standard door size of 1300*1800. The catalyst is put in through the side door via the catalyst loading system outside the reactor. Considering the possibility of dust accumulation on the catalyst surface, each reactor layer needs to be equipped with a catalyst maintenance manhole door, with a standard manhole door size of 600*800.

[0031] SCR denitrification commonly uses vanadium-titanium-based catalysts, which are classified into three types according to their appearance: honeycomb, flat plate, and corrugated plate. These three types of catalysts have similar mineral compositions, all using TiO2 (content about 80-90%) as the support, V2O5 (content about 1-2%) as the active material, and WO3 or MoO3 (content about 3-7%) as auxiliary active materials, and have the same chemical properties.

[0032] The SCR denitrification reactor 1 adopts a fixed bed. The horizontal section of the inlet flue of the reactor is equipped with a flow-regulating grid 16 device to optimize the temperature, velocity and component distribution of the flue gas. The flow-regulating grid can maximize the uniformity of the distribution of flue gas parameters entering the SCR reaction tower and minimize the resistance of the flue system. It can also be used as a dust screen to prevent large ash particles from clogging the catalyst.

[0033] The flue gas bypass system includes: a high-temperature flue gas bypass 7, a low-temperature flue gas bypass 5, an SCR flue gas bypass 9, and a regulating valve for the flue gas bypass.

[0034] SCR reactors are generally arranged between 320℃ and 400℃. In boilers, the flue gas temperature is most suitable between the primary economizer and the secondary economizer. When the boiler is running at low load, if the flue gas temperature at the SCR inlet is lower than 320℃, the high-temperature bypass is opened. The high-temperature bypass comes from before the primary economizer. The flue gas regulating valves of the high-temperature bypass and the SCR inlet bypass work together to ensure that the flue gas temperature after mixing is higher than 320℃, which can meet the denitrification requirements.

[0035] When the boiler is running at high load, if the flue gas temperature at the SCR inlet exceeds 400℃, the catalyst may sinter if its instantaneous temperature resistance exceeds 400℃. Therefore, it is necessary to open the low-temperature flue gas bypass 5. The low-temperature flue gas bypass 5 comes from the clean flue gas at the outlet of the induced draft fan. The flue gas at the outlet of the boiler induced draft fan is mostly above the flue gas dew point of 15-20℃, about 80-100℃, and the flue gas at the outlet of the induced draft fan has been deodorized by atmospheric pollutants such as NOx, SO2, and dust. It is clean flue gas and will not increase the burden on the SCR reactor. By cooperating with the flue gas regulating valves of the low-temperature bypass and the SCR inlet bypass, the temperature of the mixed flue gas is below 400℃, which can meet the denitrification requirements.

[0036] When the catalyst needs to be replaced due to deactivation, or when the reactor requires maintenance, the SCR inlet and outlet flue gas dampers can be closed and the SCR flue gas bypass 9 opened to allow for offline catalyst replacement without affecting boiler shutdown. This provides convenience for future operation. The flue gas bypass valve is high-temperature resistant, has good sealing performance, and a leakage rate of ≤0.5%.

[0037] The acoustic sootblower system 3 includes a compressed air storage tank and acoustic sootblower 3; SCR reactors generally use acoustic sootblower 3 for cleaning, with multiple sootblowers installed on each catalyst layer; sootblowing control is integrated into the unit control system. The number and arrangement of sootblowers can clean up as much ash as possible from the catalyst and minimize the risk of catalyst failure due to dead zones, thus reducing denitrification efficiency.

[0038] The sonic soot blower 3 uses compressed air from a storage tank, with a pressure typically between 0.4 and 0.6 MPa. The sonic soot blower has a wide operating range, and within the required range, it can uniformly remove dust from the flue gas without leaving any dead zones. Simultaneously, the sonic soot blower does not adversely affect the catalyst or the SCR reactor itself. The noise generated during operation of the sonic soot blower 3 is always less than the permissible levels set by the International Organization for Safety and Health (OSHA), and will not cause noise pollution to the external environment or harm to human health.

[0039] Dust accumulation on the catalyst surface not only reduces the catalyst's efficiency in removing NOx from flue gas but also increases the pressure drop of the flue gas passing through the catalyst. An acoustic soot blower 3 is used to remove the dust from the catalyst surface, and then this dust flows out of the catalyst with the flue gas. The soot blowing system continuously blows dust from the catalyst according to a set program.

[0040] The rectifier grid 16 is a flow guiding and equalizing device, designed with CFD assistance to ensure that the maximum deviation of the ammonia-nitrogen molar ratio at the SCR reactor inlet is no more than ±5% of the average value; the degree of non-uniformity in the mixing of ammonia and flue gas must be less than 5% to ensure the denitrification rate and ammonia slip rate; the rectifier grid 16 adopts an inclined structure, which can more effectively adjust the flue gas flow field, improve the flow field uniformity, further optimize the flue gas flow field, and improve the denitrification efficiency of the SCR system.

[0041] The design of SCR denitrification reactor 1 fully considers its coordination and aesthetics with the surrounding equipment layout. The reactor should be designed so that the flue gas flows vertically downwards. Necessary anti-wear and anti-corrosion measures are designed for parts of the reactor that are prone to wear and corrosion. All kinds of reinforcing plates and supports inside the reactor should be designed to prevent dust accumulation, and thermal expansion compensation measures should be considered. The reactor adopts a heat preservation structure and is equipped with a heat preservation layer to ensure that the temperature change of the flue gas passing through the reactor is less than 2°C.

[0042] To ensure normal operation, startup, and completion of testing and performance evaluation, a sufficient number of openings should be installed at the lower end of the reactor. The specific number and requirements should be determined by the testing unit based on the spatial layout of the reactor.

[0043] Low-temperature flue gas bypass 5 is connected to SCR inlet flue 11, and a low-temperature flue gas bypass regulating valve 6 is installed on low-temperature flue gas bypass 5. High-temperature flue gas bypass 7 is connected to SCR inlet flue 11, and a high-temperature flue gas bypass regulating valve 8 is installed on high-temperature flue gas bypass 7.

[0044] When the boiler load is too low, causing the SCR inlet flue gas temperature to be below 320℃, the temperature is increased by using the high-temperature flue gas bypass 7 to prevent catalyst deactivation. When the boiler load is too high, causing the SCR inlet flue gas temperature to be above 400℃, the temperature is decreased by using the low-temperature flue gas bypass 5 to prevent catalyst sintering. In other words, when the boiler load fluctuates within the range of 30%-110%, the SCR inlet flue gas temperature can be maintained between 320℃ and 400℃, ensuring the catalyst's reactivity, meeting the denitrification efficiency requirements, reducing ammonia slip, and extending the catalyst's chemical lifespan.

[0045] When the boiler load is lower than the minimum load designed for the SCR denitrification reactor 1, the temperature displayed by the temperature transmitter installed on the SCR inlet flue 11 will inevitably be lower than 320℃. It is necessary to raise the temperature of the flue gas to ensure the denitrification efficiency. At this time, the high-temperature flue gas bypass regulating valve 8 on the high-temperature flue gas bypass 7 and the SCR inlet flue regulating valve 12 should work together to display the temperature of the mixed flue gas in real time on the temperature transmitter, so that the temperature of the mixed flue gas is above 320℃. At the same time, it can be set to interlock logic automatic control.

[0046] When the boiler load exceeds the maximum load of the designed SCR denitrification reactor 1, the temperature displayed by the temperature transmitter installed on the SCR inlet flue 11 will inevitably be higher than 400℃. It is necessary to cool the flue gas to ensure denitrification efficiency and prevent the catalyst from sintering. At this time, the low-temperature flue gas bypass regulating valve 6 on the low-temperature flue gas bypass 5 and the SCR inlet flue gas regulating valve 12 should work together to display the temperature of the mixed flue gas in real time on the temperature transmitter, so that the temperature of the mixed flue gas is kept below 400℃. At the same time, it can be set to interlock logic automatic control.

[0047] When the SCR denitrification reactor 1 malfunctions and needs to be taken offline for maintenance, first open the SCR flue gas bypass regulating valve 10 on the SCR flue gas bypass 9, and then simultaneously close the flue gas regulating valve at the SCR inlet and the flue gas regulating valve at the SCR outlet; so that the flue gas passes through the SCR flue gas bypass 9, and the SCR denitrification reactor 1 is taken offline, creating conditions for maintenance, while not affecting the normal operation of the boiler unit.

[0048] Expansion joints are installed on necessary local pipe sections in the flue gas system to absorb the expansion of straight pipes and minor non-axial displacement. All equipment, pipes, and expansion joints in the flue gas system are insulated. The flue gas system can withstand the following loads: its own weight, wind load, seismic load, ash accumulation load, and the weight of the insulation. To minimize the pressure drop of the flue gas system, its layout, shape, and internal components (such as baffles and guide plates at bends) should be optimized. Desulfurization flues should be circular pipes.

[0049] Anti-corrosion flues can be installed, with a minimum wall thickness of 6mm, and a certain corrosion allowance should be considered. The flue should be an airtight welded structure, and the weld treatment should meet the requirements of use and anti-corrosion lining. All non-flange connections should be continuously welded. The flue exterior should be adequately reinforced and supported to prevent vibration and shock, and the design should ensure stable operation under various flue gas temperatures and pressures.

[0050] All flues should be equipped with a sufficient number and size of manholes and ash removal holes in appropriate locations to facilitate maintenance and inspection of the flues (including expansion joints and dampers). Additionally, manholes should be separately insulated from the flue wall for easy opening. To ensure that the stress on equipment connected to the flue is within permissible limits, the thermal expansion of the flue system must be considered, and this thermal expansion should be controlled through expansion joints. The sliding supports of the flue should use PTFE (polytetrafluoroethylene) components for their sliding base plates.

[0051] An NH3 analysis system is installed at the outlet of SCR denitrification reactor 1; the NH3 analysis system is a device or apparatus used for qualitative and quantitative analysis of ammonia (NH3). Pressure and temperature measuring devices are installed at the inlet and outlet of SCR denitrification reactor 1, and differential pressure measuring devices are installed at the inlet and outlet of each catalyst layer.

[0052] The vanadium-titanium catalyst 2 is arranged in multiple layers at intervals, and an acoustic soot blower 3 is arranged on the upper surface of the vanadium-titanium catalyst 2. Several acoustic soot blowers 3 are arranged, and one end of the acoustic soot blower 3 is connected to a compressed air tank. The number and arrangement of the acoustic soot blowers 3 should be able to blow away as much ash as possible from the catalyst, and should avoid catalyst failure due to dead corners, which would lead to a decrease in denitrification efficiency. Each layer of catalyst should be equipped with a soot blower, and the soot blowing control should be integrated into the unit's DCS, ensuring the correctness of the logic. The DCS is existing technology.

[0053] Several ammonia injection grids (4) are spaced apart and connected to ammonia gas pipelines. The ammonia gas required as the reducing agent for the SCR reactor is injected through the injection grids. 20% ammonia water, delivered by an ammonia water transfer pump, is atomized in the ammonia water evaporator through spray guns. Simultaneously, hot air, heated by an electric heater and delivered by a dilution fan, enters the ammonia water evaporator to evaporate the atomized ammonia water into ammonia gas, ensuring that the ammonia gas concentration does not exceed the explosive limit. The prepared and diluted ammonia gas is metered and delivered to the injection grids. The injection grids are divided into several channels leading to each injection layer. Nitrogen oxides react with the reducing agent in the gas phase. A small amount of gaseous ammonia is released into the atmosphere.

[0054] The working principle of the ammonia injection grid 4 is that a large number of ammonia pipes extend into the flue gas duct at intersections, each pipe equipped with numerous small nozzles. Its main principle is to use liquid ammonia or ammonia water as a reducing agent, mixing it with air and then injecting it into the upstream flue gas duct of the SCR reactor. Under the action of the catalyst, ammonia reacts chemically with NOx in the flue gas to produce nitrogen and water, thereby reducing the NOx emission concentration in the flue gas. This chemical reaction process requires that ammonia and NOx be fully mixed before entering the catalyst layer; the ammonia injection grid 4 is the key device to achieve uniform ammonia distribution. The horizontal and vertical injection rates of the ammonia injection grid 4 are adjustable, offering high controllability. This allows for the uniform mixing of ammonia and NOx under different operating conditions by adjusting the ammonia injection rate in each area, improving denitrification efficiency. Numerical simulations were used to analyze the mixing effect of flue gas and ammonia under the original ammonia injection grid 4 structure, and its structure and layout were optimized and adjusted accordingly. For example, reducing the diameter of the ammonia injection holes on the ammonia injection pipe and adopting a configuration with large-diameter holes on both sides and small-diameter holes in the middle can enhance the penetration of the ammonia jet and improve the mixing uniformity of flue gas and ammonia. Through modular design of the ammonia injection grid 4, flow turbulence devices, nozzle anti-clogging functions, injection volume adjustment, numerical simulation optimization, and automatic control systems, the performance of the ammonia injection grid 4 can be effectively improved, ensuring the safe and stable operation of the SCR system.

[0055] The other end of the SCR denitrification reactor 1 is the SCR outlet flue 13, which is connected to the outlet end of the SCR denitrification reactor 1. An SCR outlet flue regulating valve 14 is installed on the SCR outlet flue 13, and an SCR flue gas bypass 9 is installed at one end of the SCR outlet flue 13. One end of the SCR flue gas bypass 9 is connected to the SCR inlet flue 11, and the other end of the SCR flue gas bypass 9 is connected to the SCR outlet flue 13. An SCR flue gas bypass regulating valve 10 is installed on the SCR flue gas bypass 9.

[0056] A maintenance lifting electric hoist 15 is installed at one end of the SCR denitrification reactor 1. The maintenance lifting electric hoist includes electric hoist 15 and / or manual chain hoist, and should be installed on I-beam rails or bridge rails; the electric hoist should be permanently installed, with a lifting capacity of 2t or more; the operating power supply of all electric lifting facilities should be a low-voltage safety power supply.

[0057] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. An SCR denitration system adapted to changes in the working conditions of a boiler, characterized in that, The application relates to a flue gas denitration system, which comprises an SCR denitration reactor, a vanadium-titanium catalyst arranged at one end of a rectifying grid arranged in the SCR denitration reactor, an SCR inlet flue arranged at one end of the SCR denitration reactor, an SCR inlet flue adjusting valve arranged on the SCR inlet flue, an ammonia injection grid arranged at one end of the SCR inlet flue adjusting valve, and a low-temperature flue gas bypass and a high-temperature flue gas bypass arranged at one end of the SCR inlet flue.

2. The SCR denitration system adaptive to the working condition change of a boiler according to claim 1, characterized in that, The low-temperature flue gas bypass is connected with the SCR inlet flue, and a low-temperature flue gas bypass adjusting valve is arranged on the low-temperature flue gas bypass.

3. The SCR denitration system adaptive to the working condition change of a boiler according to claim 1, characterized in that, The high-temperature flue gas bypass is connected with the SCR inlet flue, and a high-temperature flue gas bypass adjusting valve is arranged on the high-temperature flue gas bypass.

4. The SCR denitration system adaptive to the working condition change of a boiler according to claim 1, characterized in that, A plurality of layers of the vanadium-titanium catalyst are arranged at intervals, and an acoustic soot blower is arranged on the upper surface of the vanadium-titanium catalyst.

5. The SCR denitration system adaptive to the change of the working condition of a boiler according to claim 4, characterized in that, A plurality of acoustic soot blowers are arranged, and one end of each acoustic soot blower is connected with a compressed air tank.

6. The SCR denitration system adaptive to the working condition change of a boiler according to claim 1, characterized in that, A plurality of ammonia injection grids are arranged at intervals, and the ammonia injection grids are connected with ammonia pipelines.

7. The SCR denitration system adaptive to the change of the working condition of a boiler according to claim 1, characterized in that, The other end of the SCR denitration reactor is an SCR outlet flue connected with the outlet end of the SCR denitration reactor.

8. The SCR denitration system adaptive to the working condition change of a boiler according to claim 7, characterized in that, An SCR outlet flue adjusting valve is arranged on the SCR outlet flue, and an SCR flue gas bypass is arranged at one end of the SCR outlet flue.

9. The SCR denitration system adaptive to the change of the working condition of a boiler according to claim 8, characterized in that, One end of the SCR flue gas bypass is connected with the SCR inlet flue, the other end of the SCR flue gas bypass is connected with the SCR outlet flue, and an SCR flue gas bypass adjusting valve is arranged on the SCR flue gas bypass.

10. The SCR denitration system adaptive to the change of the working condition of a boiler according to claim 1, characterized in that, A maintenance electric hoist is arranged at one end of the SCR denitration reactor.

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