Catalytic denitration device for industrial tail gas

Abstract

The utility model relates to a catalytic denitration device for industrial tail gas, which comprises a tail gas conveying header pipe, a catalytic device is communicated with the tail gas conveying header pipe, and the catalytic device comprises a catalytic tank and a catalyst layer arranged in the catalytic tank. A first heat exchanger, a centrifugal compressor, a first online chromatographic instrument, a first air mixer, a second heat exchanger, a first temperature sensor, a first gas flow sensor and a second online chromatographic instrument are arranged on the tail gas conveying header pipe; the first air mixer is communicated with the outlet end of the second heat exchanger, the second heat exchanger is provided with an air supply header pipe, the air supply header pipe is provided with a third online chromatographic instrument, a second air mixer, a second gas flow sensor, a first regulating valve, a second temperature sensor and a fan, and the second air mixer is communicated with an ammonia water vaporizer. The temperature difference between the tail gas and the reducing gas flow can be reduced, so that the actual flow of the ammonia-containing gas can be fed back more intuitively. And the device is convenient to adjust and use, and has a wide market prospect.

Description

Technical Field

[0001] The utility model relates to the field of catalytic denitration equipment for tail gas, and specifically relates to a catalytic denitration device for industrial tail gas. Background Technique

[0002] The melting furnace for aluminum is an important high-temperature production equipment in the aluminum processing and smelting process. Its main function is to melt raw materials such as aluminum ingots and waste aluminum products, and then after adjusting the chemical composition, it provides aluminum liquid that meets the quality requirements for subsequent production processes. The flue gas of the melting furnace for aluminum belongs to non-ferrous metal smelting flue gas, which has the characteristics of small flue gas volume, high NO x concentration, and large fluctuations. Specifically, the typical production of the melting furnace for aluminum mainly includes stages such as raw material charging, melting, stirring, slag skimming, refining, heat preservation, and furnace cleaning. During the smelting process of the melting furnace for aluminum using natural gas or coal gas as fuel, the melting of aluminum materials needs to be achieved through direct heating by flame combustion. The high and low of the flame combustion temperature directly affects the melting speed of aluminum materials. Research shows that there are three types of NO x formation in the flue gas: fuel type (F-NO x ), thermal type (T-NO x ), and prompt type (P-NO x ). Since the air contains a large amount of nitrogen, these nitrogen gases are oxidized to form NO x under high-temperature combustion conditions. This part of NO x is called thermal type NO x . The emission of thermal type NO x has an exponential function relationship with the combustion temperature. The higher the temperature, the faster its generation speed and the larger the generation amount. The melting furnace for aluminum is a gas furnace type, and the flame center temperature of the combustion system is close to 1500 °C. Therefore, thermal type NO x is the main form of NO x generated during the combustion process. The emission standards for NO x in the flue gas of the melting furnace for aluminum processing and smelting have certain industry and regional differences.

[0003] Denitration technologies are mainly divided into pre-combustion, in-combustion, and post-combustion denitration. Pre-combustion denitration technologies include hydrodenitration and washing and screening; in-combustion denitration technologies are mainly low-nitrogen combustion technologies; post-combustion denitration technologies mainly include selective non-catalytic reduction denitration, selective catalytic reduction denitration, activated carbon adsorption, and electron beam denitration, etc. Selective catalytic reduction denitration specifically refers to the selective oxidation-reduction reaction of NO x in the flue gas with ammonia under the action of a catalyst, generating pollution-free N2 and H20. The selective catalytic reduction denitration technology is completed in the boiler tail reactor at a flue gas temperature of 300 °C to 400 °C, and the denitration efficiency can reach more than 90%. The principle of selective catalytic reduction denitration is: ; According to the above principle, in selective catalytic reduction denitration, a preset amount of ammonia needs to be transported into the tail gas to react with the nitrogen monoxide contained in the tail gas to complete the treatment of nitrogen monoxide in the tail gas. If the ammonia transportation amount is insufficient, some nitrogen monoxide in the tail gas will still not be treated, while if the ammonia transportation amount exceeds the standard, ammonia contained in the tail gas will also cause pollution. The actual situation is that the temperature of the tail gas discharged from the aluminum melting furnace is relatively high and the temperature of the tail gas discharged from the aluminum melting furnace changes fluctuantly with the load of the aluminum melting furnace; while the temperature of the reducing gas containing ammonia injected into the tail gas is relatively low, and the reducing gas will directly exchange heat with the tail gas discharged from the aluminum melting furnace after being transported to the tail gas, resulting in further expansion of the reducing gas in the tail gas, and thus it is very difficult to control the actual transportation flow rate of ammonia transported into the tail gas through the reducing gas flow to the reasonable preset transportation flow rate of ammonia. To sum up, due to the temperature difference between the tail gas discharged from the aluminum melting furnace and the reducing gas containing ammonia, it is difficult to make the actual ammonia injection amount into the tail gas discharged from the aluminum melting furnace reach the preset range, resulting in a difference between the actual treatment amount and the theoretical treatment amount of nitrogen monoxide in the tail gas discharged from the aluminum melting furnace. Furthermore, there is room for improvement in making the actual flow rate of ammonia transportation better fit the theoretical required ammonia amount of the tail gas discharged from the aluminum melting furnace, so as to more fully treat the nitrogen monoxide in the tail gas discharged from the aluminum melting furnace to meet the market demand. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the utility model provides a catalytic denitration device for industrial tail gas that can reduce the temperature difference between the tail gas and the reducing gas flow, thereby more intuitively reflecting the actual flow rate of the ammonia-containing gas, to overcome the defects in the prior art.

[0005] The technical solution adopted by the utility model is: a catalytic denitration device for industrial tail gas, including a main tail gas transportation pipe. The outlet end of the main tail gas transportation pipe is connected to a catalytic device. The catalytic device includes a catalytic tank and a catalyst layer arranged in the catalytic tank. Along the direction from near the catalytic device to far from the catalytic device, the main tail gas transportation pipe is successively provided with a cold source channel of a first heat exchanger, a centrifugal compressor, a first on-line chromatograph, a first air mixer, a heat source channel of a second heat exchanger, a first temperature sensor, a first gas flow sensor, and a second on-line chromatograph; the first air mixer is connected to the outlet end of the cold source channel of the second heat exchanger. A make-up air main pipe is arranged at the inlet end of the cold source channel of the second heat exchanger. Along the direction from near the second heat exchanger to far from the second heat exchanger, the make-up air main pipe is successively provided with a third on-line chromatograph, a second air mixer, a second gas flow sensor, a first regulating valve, a second temperature sensor, and a blower. An ammonia vaporizer is connected to the second air mixer.

[0006] Preferably, a third air mixer is provided on the tail gas delivery main pipe between the first gas flow sensor and the second on-line chromatograph. A fourth on-line chromatograph is provided between the third air mixer and the first gas flow sensor. The first air mixer, the second air mixer and the third air mixer all include an air mixing tank and a gas guiding elbow, a gas guiding cone and a spiral blade sequentially arranged in the air mixing tank along the direction from the inlet end of the air mixing tank to the outlet end of the air mixing tank. The gas guiding elbow of the first air mixer is communicated with the cold source channel of the second heat exchanger. The air mixing tanks of the first air mixer and the third air mixer are both installed on the tail gas delivery main pipe. The air mixing tank of the second air mixer is installed on the air supplement main pipe. The ammonia vaporizer is communicated with the gas guiding elbow of the second air mixer.

[0007] Preferably, a third gas flow sensor is provided on the tail gas delivery main pipe between the first air mixer and the second heat exchanger. The gas guiding elbow of the first air mixer is communicated with the cold source channel of the second heat exchanger through a variable temperature gas delivery pipe. The air supplement main pipe between the second gas flow sensor and the first regulating valve and the gas guiding elbow of the third air mixer are communicated through an air supplement branch pipe. A fourth gas flow sensor and a second regulating valve are respectively provided on the air supplement branch pipe and the variable temperature gas delivery pipe.

[0008] Preferably, an ammonia vaporization pipe is provided on the gas guiding elbow of the second air mixer. A check valve, a liquid flow sensor, a third regulating valve, a booster pump and an ammonia water storage tank are sequentially arranged on the ammonia vaporization pipe along the direction from near the second air mixer to far from the second air mixer. The ammonia vaporizer is installed on the ammonia vaporization pipe between the check valve and the liquid flow sensor.

[0009] Preferably, a liquid level sensor is provided on the ammonia water storage tank.

[0010] Preferably, the inlet end of the catalytic tank of the catalytic device is communicated with the tail gas delivery main pipe. A denitrification tail gas discharge pipe is provided at the inlet end of the catalytic tank of the catalytic device. The cold source channel of a third heat exchanger is provided on the tail gas delivery main pipe between the centrifugal compressor and the first on-line chromatograph. The heat source channel of the third heat exchanger is communicated with the denitrification tail gas discharge pipe.

[0011] Preferably, the catalytic device further includes a catalytic delivery pipe provided on the catalytic tank and stop valves respectively provided on the catalytic delivery pipes on both sides of the catalytic tank. The number of the catalytic devices is at least two, and several catalytic devices are connected in parallel with each other.

[0012] The beneficial effects of the present utility model are as follows: First, in the present utility model, the tail gas is first indirectly heat-exchanged with the ammonia-containing compressed air that is conveyed to the heat source channel of the second heat exchanger and the cold source channel of the second heat exchanger, so that the staff can more intuitively judge whether the component parameters of the ammonia-containing compressed air fed back by the third on-line chromatograph and the flow parameters of the ammonia-containing compressed air fed back by the fourth gas flow sensor installed on the variable-temperature gas conveying pipe meet the demand for the supply of ammonia components in the ammonia-containing compressed air by the nitric oxide-containing tail gas after the component parameters are fed back by the fourth on-line chromatograph and the flow parameters are fed back by the third gas flow sensor, reducing the technical problem that the treatment of nitric oxide in the tail gas deviates from the theoretical treatment amount due to insufficient supply of ammonia components to the tail gas.

[0013] Then, along the direction from near the catalytic device to far from the catalytic device, the main tail gas conveying pipe of the present utility model is successively provided with a cold source channel of a first heat exchanger, a centrifugal compressor, a first on-line chromatograph, a first air mixer, a heat source channel of a second heat exchanger, a first temperature sensor, a first gas flow sensor, and a second on-line chromatograph. The installation of the first on-line chromatograph and the second on-line chromatograph is for facilitating the feedback of component parameters.

[0014] Finally, a liquid level sensor is arranged on the ammonia water storage tank of the present utility model; the installation of the liquid level sensor is convenient for feeding back liquid level parameters.

[0015] The present utility model has the advantages of simple structure, convenient operation, ingenious design, greatly improving the work efficiency, having good social and economic benefits, and being a product easy to promote and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of the present utility model.

[0017] Figure 2 is Figure 1 a partially enlarged schematic view of detail A.

[0018] Figure 3 is Figure 1 a partially enlarged schematic view of detail B. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] Such as Figures 1 to 3As shown in the figure, a catalytic denitration device for industrial tail gas includes a main tail gas delivery pipe 1. The outlet end of the main tail gas delivery pipe 1 is connected to a catalytic device. The catalytic device includes a catalytic tank 2 and a catalyst layer 3 arranged in the catalytic tank 2. The catalyst layer 3 uses a vanadium-titanium-based denitration catalyst. Along the direction from near the catalytic device to far from the catalytic device, the main tail gas delivery pipe 1 is sequentially provided with a cold source channel of a first heat exchanger 4, a centrifugal compressor 5, a first online chromatograph 6, a first air mixer, a heat source channel of a second heat exchanger 7, a first temperature sensor 8, a first gas flow sensor 9, and a second online chromatograph 10. The outlet end of the first air mixer is connected to the cold source channel of the second heat exchanger 7. A make-up air main pipe 11 is arranged at the inlet end of the cold source channel of the second heat exchanger 7. Along the direction from near the second heat exchanger 7 to far from the second heat exchanger 7, the make-up air main pipe 11 is sequentially provided with a third online chromatograph 12, a third temperature sensor 39, a second air mixer, a second gas flow sensor 13, a first regulating valve 14, a second temperature sensor 15, and a fan 16. An ammonia vaporizer 17 is connected to the second air mixer.

[0020] Since the load of the aluminum melting furnace is variable, the nitrogen monoxide contained in the tail gas discharged from the aluminum melting furnace is also variable. When the concentration of nitrogen monoxide in the tail gas increases, the concentration of ammonia in the supplementary gas containing ammonia transported to the tail gas transport main pipe 1 through the air supply main pipe 11 also needs to increase accordingly. However, ammonia is a combustible gas with an explosion limit. If the concentration of ammonia is within the explosion limit, it will cause danger. Therefore, when the concentration of nitrogen monoxide in the tail gas increases to a preset range, the tail gas needs to be diluted to reduce the concentration of nitrogen monoxide in the tail gas. Therefore, a third air mixer is provided on the tail gas transport main pipe 1 between the first gas flow sensor 9 and the second online chromatograph 10 of the present product. An fourth online chromatograph 18 is provided between the third air mixer and the first gas flow sensor 9. The first air mixer, the second air mixer and the third air mixer all include an air mixing tank 19 and a gas guiding elbow 20, a gas guiding cone 21 and a spiral blade 22 arranged in sequence in the air mixing tank 19 along the direction from the inlet end to the outlet end of the air mixing tank 19. The gas guiding elbow 20 of the first air mixer is communicated with the cold source channel of the second heat exchanger 7. The air mixing tanks 19 of the first air mixer and the third air mixer are both installed on the tail gas transport main pipe 1. The air mixing tank 19 of the second air mixer is installed on the air supply main pipe 11, and the ammonia vaporizer 17 is communicated with the gas guiding elbow 20 of the second air mixer. Further, a third gas flow sensor 23 is provided on the tail gas transport main pipe 1 between the first air mixer and the second heat exchanger 7. The gas guiding elbow 20 of the first air mixer and the cold source channel of the second heat exchanger 7 are connected through a variable temperature gas transport pipe 24. The air supply main pipe 11 between the second gas flow sensor 13 and the first regulating valve 14 and the gas guiding elbow 20 of the third air mixer are connected through an air supply branch pipe 25. A fourth gas flow sensor 26 and a second regulating valve 27 are respectively provided on the air supply branch pipe 25 and the variable temperature gas transport pipe 24. The tail gas after component analysis by the second online chromatograph 10 is then transported to the tail gas in the tail gas transport main pipe 1 through the air supply branch pipe 25 and the third air mixer to supply compressed air. The compressed air is used as an inert gas to dilute the tail gas discharged from the aluminum melting furnace, thereby reducing the concentration of nitrogen monoxide in the diluted tail gas and providing feedback through the fourth online chromatograph 18. Further, an ammonia vaporization pipe 28 is provided on the gas guiding elbow 20 of the second air mixer of the present product. The ammonia vaporization pipe 28 is sequentially provided with a one-way valve 29, a liquid flow sensor 30, a third regulating valve 31, a booster pump 32 and an ammonia water storage tank 33 along the direction from near the second air mixer to far from the second air mixer. The ammonia vaporizer 17 is installed on the ammonia vaporization pipe 28 between the one-way valve 29 and the liquid flow sensor 30. A liquid level sensor 34 is provided on the ammonia water storage tank 33.

[0021] The inlet end of the catalytic tank 2 of the described catalytic device is connected to the main exhaust gas delivery pipe 1. A denitrification exhaust gas discharge pipe 35 is provided at the inlet end of the catalytic tank 2 of the catalytic device. A cold source channel of a third heat exchanger 36 is provided on the main exhaust gas delivery pipe 1 between the centrifugal compressor 5 and the first on-line chromatograph 6. The heat source channel of the third heat exchanger 36 is connected to the denitrification exhaust gas discharge pipe 35. The catalytic device further includes a catalytic delivery pipe 37 provided on the catalytic tank 2 and stop valves 38 respectively provided on the catalytic delivery pipes 37 on both sides of the catalytic tank 2. The number of the catalytic devices is at least two, and several of the catalytic devices are connected in parallel with each other. Installing several catalytic devices connected in parallel facilitates continuous catalysis of the exhaust gas and avoids a total shutdown caused by the need for maintenance of the catalytic device in the working state.

[0022] The usage method of this product is as follows. As Figures 1 to 3 shown, it includes the following steps:

[0023] S1. The main exhaust gas delivery pipe 1 receives the exhaust gas released from the aluminum melting furnace. First, it passes through the second on-line chromatograph 10 for the first analysis of the component content. The staff makes a judgment based on the results fed back by the second on-line chromatograph 10. If the concentration of nitric oxide fed back by the second on-line chromatograph 10 is within the preset range or the concentration of nitric oxide fed back by the second on-line chromatograph 10 is lower than the preset range, there is no need to supply compressed air to the main exhaust gas delivery pipe 1 through the air supply branch pipe 25. If the concentration of nitric oxide fed back by the second on-line chromatograph 10 exceeds the preset range, it is necessary to supply compressed air to the main exhaust gas delivery pipe 1 through the air supply branch pipe 25 to reduce the concentration of nitric oxide in the exhaust gas transported in the main exhaust gas delivery pipe 1. The specific steps of supplying compressed air to the main exhaust gas delivery pipe 1 through the air supply branch pipe 25 include first turning on the fan 16. The outside air enters the main air supply pipe 11 and is sent to the air supply branch pipe 25 after the temperature is fed back by the second temperature sensor 15. The second regulating valve 27 on the air supply branch pipe 25 is adjusted according to the concentration parameter of nitric oxide fed back by the second on-line chromatograph 10 and the load of the aluminum melting furnace. After the flow parameter is fed back by the fourth gas flow sensor 26 on the air supply branch pipe 25, it is supplied to the third air mixing device and mixed with the exhaust gas transported to the third air mixing device through the main exhaust gas delivery pipe 1, and then successively sent to the heat source channel of the second heat exchanger 7 after the component parameters of the mixed exhaust gas are fed back by the fourth on-line chromatograph 18, the flow parameter is fed back by the first gas flow sensor 9, and the temperature parameter is fed back by the first temperature sensor 8.

[0024] S2. Turn on the booster pump 32 and adjust the opening degrees of the first regulating valve 14 and the third regulating valve 31 according to the component parameters of the tail gas after mixing feedback by the fourth online chromatograph 18, the flow parameters feedback by the first gas flow sensor 9, and the temperature parameters feedback by the first temperature sensor 8. During the transportation of the ammonia water stored in the ammonia water storage tank 33 through the ammonia water vaporization pipe 28, it passes through the ammonia water vaporizer 17 to vaporize into ammonia-containing steam and then is transported to the second air mixer. The flow parameters of the ammonia water transported through the ammonia water vaporization pipe 28 are feedback by the liquid flow sensor 30; the partial compressed air transported through the tail gas transportation main pipe 1 after the second temperature sensor 15 feedbacks the temperature continues to move forward along the tail gas transportation main pipe 1 and is transported to the second air mixer. During this period, the gas flow parameters are feedback by the second gas flow sensor 13. The compressed air and the ammonia-containing steam transported to the second air mixer are fully mixed to form ammonia-containing compressed air, which is discharged from the second air mixer and then feedbacks the temperature parameters by the third temperature sensor 39 and the component parameters by the third online chromatograph 12, and then is transported to the cold source channel of the second heat exchanger 7 for countercurrent heat exchange with the tail gas continuously transported to the heat source channel of the second heat exchanger 7; the ammonia-containing compressed air after heat exchange by the second heat exchanger 7 and the tail gas after heat exchange by the second heat exchanger 7 are jointly transported to the first air mixer to complete full mixing and form catalytic conversion gas. During this period, it is also necessary to further adjust the opening degree of the second regulating valve 27 on the variable temperature gas transportation pipe 24 according to the parameters feedback by the third gas flow sensor 23, so that the ammonia content in the ammonia-containing compressed air transported through the variable temperature gas transportation pipe 24 can be within the concentration range required for nitrogen monoxide in the tail gas after heat exchange by the second heat exchanger 7.

[0025] S3. The catalytic conversion gas continues to move forward along the tail gas transportation main pipe 1 and the first online chromatograph 6 feedbacks the parameters of each component in the catalytic conversion gas again, so as to further adjust the flow parameters of the ammonia-containing compressed air transported to the first air mixer to further meet the ammonia concentration requirement of the tail gas after heat exchange by the second heat exchanger 7. Then it is sent to the cold source channel of the third heat exchanger 36 for countercurrent heat exchange with the medium continuously transported to the heat source channel of the third heat exchanger 36 to complete the first-stage heating of the catalytic conversion gas, and then sent to the centrifugal compressor 5 for compression work to complete the second-stage heating of the catalytic conversion gas; finally, it is sent to the cold source channel of the first heat exchanger 4 for countercurrent heat exchange with the heat source medium continuously transported to the heat source channel of the first heat exchanger 4 to complete the third-stage heating of the catalytic conversion gas, and then sent to the catalytic equipment in the working state. The catalyst layer 3 in the catalytic equipment in the working state is used to carry out catalytic reaction on the catalytic conversion gas after the third-stage heating, and then the tail gas for treating nitrogen monoxide is transported through the denitrification tail gas discharge pipe 35 to the heat source channel of the third heat exchanger 36 for countercurrent heat exchange with the medium continuously transported to the cold source channel of the third heat exchanger 36, and then sent to the next process for further treatment.

[0026] In this embodiment, by first indirectly exchanging heat between the exhaust gas delivered to the heat source channel of the second heat exchanger 7 and the ammonia-containing compressed air delivered to the cold source channel of the second heat exchanger 7, it enables the staff to more intuitively judge whether the component parameters of the ammonia-containing compressed air fed back by the third on-line chromatograph 12 and the flow rate parameters of the ammonia-containing compressed air fed back by the fourth gas flow sensor 26 installed on the variable temperature gas delivery pipe 24 meet the demand for the supply of ammonia components in the ammonia-containing compressed air by the nitric oxide-containing exhaust gas after the component parameters are fed back by the fourth on-line chromatograph 18 and the flow rate parameters are fed back by the third gas flow sensor 23, thus reducing the technical problem that the treatment of nitric oxide in the exhaust gas deviates from the theoretical treatment amount due to insufficient supply of ammonia components to the exhaust gas.

[0027] The above-described embodiments are only the preferred embodiments of the present invention, and do not limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made according to the structure, features, and principles described in the scope of the present invention patent shall be included within the scope of the patent application of the present invention.

Claims

1. A catalytic denitration device for industrial tail gas, characterized in that: The invention comprises an exhaust gas transport main pipe (1), wherein the outlet end of the exhaust gas transport main pipe (1) is connected to a catalytic device, wherein the catalytic device comprises a catalytic tank (2) and a catalyst layer (3) arranged in the catalytic tank (2), and the exhaust gas transport main pipe (1) is provided with a cold source channel of a first heat exchanger (4), a centrifugal compressor (5), a first online chromatograph (6), a first air mixer, a hot source channel of a second heat exchanger (7), a first temperature sensor (8), a first gas flow sensor (9) and a second An online chromatograph (10); the first air mixer is connected to the outlet end of the cold source channel of the second heat exchanger (7); an air supply main pipe (11) is provided on the inlet end of the cold source channel of the second heat exchanger (7); a third online chromatograph (12), a second air mixer, a second gas flow sensor (13), a first regulating valve (14), a second temperature sensor (15) and a fan (16) are sequentially provided on the air supply main pipe (11) in a direction from close to the second heat exchanger (7) to far away from the second heat exchanger (7); and the second air mixer is connected to an ammonia vaporizer (17).

2. The catalytic denitration device for industrial tail gas according to claim 1, characterized in that: A third air mixer is provided on the exhaust gas transport main pipe (1) between the first gas flow sensor (9) and the second online chromatograph (10); a fourth online chromatograph (18) is provided between the third air mixer and the first gas flow sensor (9); the first air mixer, the second air mixer and the third air mixer all include an air mixing tank (19) and air guides arranged in sequence in the air mixing tank (19) from the inlet end to the outlet end of the air mixing tank (19). The air guide bend (20), the air guide cone (21) and the spiral blade (22), the air guide bend (20) of the first air mixer is connected to the cold source channel of the second heat exchanger (7), the air mixing tank (19) of the first air mixer and the air mixing tank (19) of the third air mixer are both installed on the exhaust gas delivery main pipe (1); the air mixing tank (19) of the second air mixer is installed on the air supply main pipe (11), and the ammonia vaporizer (17) is connected to the air guide bend (20) of the second air mixer.

3. The catalytic denitration device for industrial tail gas according to claim 2, characterized in that: A third gas flow sensor (23) is provided on the exhaust gas delivery main pipe (1) between the first air mixer and the second heat exchanger (7); the air guide elbow (20) of the first air mixer and the cold source channel of the second heat exchanger (7) are connected via a variable temperature air delivery pipe (24); the air supply main pipe (11) between the second gas flow sensor (13) and the first regulating valve (14) and the air guide elbow (20) of the third air mixer are connected via an air supply branch pipe (25); and a fourth gas flow sensor (26) and a second regulating valve (27) are provided on the air supply branch pipe (25) and the variable temperature air delivery pipe (24), respectively.

4. The catalytic denitration device for industrial tail gas according to claim 2, characterized in that: An ammonia vaporization pipe (28) is provided on the air guide elbow (20) of the second air mixer. The ammonia vaporization pipe (28) is provided with a one-way valve (29), a liquid flow sensor (30), a third regulating valve (31), a booster pump (32) and an ammonia storage tank (33) in sequence along the direction from close to the second air mixer to far away from the second air mixer. The ammonia vaporizer (17) is installed on the ammonia vaporization pipe (28) between the one-way valve (29) and the liquid flow sensor (30).

5. The catalytic denitration device for industrial tail gas according to claim 4, characterized in that: The ammonia water storage tank (33) is provided with a liquid level sensor (34).

6. The catalytic denitration device for industrial tail gas according to claim 1, characterized in that: The inlet end of the catalytic tank (2) of the catalytic device is connected to the exhaust gas transport main pipe (1), and a denitration exhaust gas emission pipe (35) is arranged on the inlet end of the catalytic tank (2) of the catalytic device. A cold source channel of a third heat exchanger (36) is arranged on the exhaust gas transport main pipe (1) between the centrifugal compressor (5) and the first online chromatograph (6), and a heat source channel of the third heat exchanger (36) is connected to the denitration exhaust gas emission pipe (35).

7. The catalytic denitration device for industrial tail gas according to claim 1, characterized in that: The catalytic device further comprises a catalytic delivery pipe (37) provided on the catalytic tank (2) and stop valves (38) respectively provided on the catalytic delivery pipes (37) on both sides of the catalytic tank (2). The number of the catalytic devices is at least two, and a plurality of the catalytic devices are connected in parallel.

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