Flue gas denitration system

Abstract

The utility model discloses a flue gas denitration system, which belongs to the technical field of flue gas purification, and comprises a gas inlet pipeline, an exhaust pipeline and a chimney, the main body of the gas inlet pipeline is arranged up and down, the exhaust pipeline is arranged downwards after being folded and is parallel to the gas inlet pipeline, and a heating device is arranged at the inlet of the gas inlet pipeline. An ammonia spraying device is arranged in an upper pipeline of the gas inlet pipeline, the gas inlet pipeline behind the ammonia spraying device is downwards communicated with a denitration reaction device in a folding manner, a gas outlet of the denitration reaction device is communicated with a decarburization reaction device, a gas outlet of the decarburization reaction device is communicated with an exhaust pipeline, and a heat exchange device which exchanges heat with the gas inlet pipeline is arranged on the exhaust pipeline. According to the flue gas denitration system, heat generated by flue gas decarburization is used as a heat source to heat the flue gas, low-consumption denitration is realized, the flue gas denitration cost is reduced, carbon monoxide in the flue gas is removed, and environmental pollution is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to flue gas purification technical field, concretely relates to a flue gas denitration system. BACKGROUND

[0002] In prior art, the basic process of flue gas purification and discharge is generally to preheat through GGH heat exchanger first, then to heat to the temperature required by denitration through heating device, to enter SCR reactor after spraying ammonia, to be emptied after denitration and heat exchange. The heating device of this kind of denitration device requires large heat, and has high energy consumption. The CO concentration in flue gas of part of industries is higher, if directly discharged after denitration, not only the resource is wasted, but also the environment is affected. SUMMARY

[0003] The utility model discloses a kind of low-energy flue gas denitration systems, can simultaneously realize the purpose of decarburization.

[0004] To achieve the above object, the specific technical scheme of the flue gas denitration system of the utility model is as follows:

[0005] A kind of flue gas denitration system, including intake pipeline, exhaust pipeline, chimney, intake pipeline main body is set up upwards along gas flow direction, exhaust pipeline is set down and is parallel with the intake pipeline, heating device is equipped at the intake pipeline import, ammonia injection device is equipped in the upper pipeline of intake pipeline, the intake pipeline after ammonia injection device is connected with the denitration reaction device downwardly, the denitration reaction device outlet is connected with decarburization reaction device, decarburization reaction device outlet is connected with exhaust pipeline, and heat exchange device for heat exchange with intake pipeline is equipped on exhaust pipeline.

[0006] Preferably, temperature measuring point is equipped on the intake pipeline after ammonia injection device.

[0007] Preferably, the decarburization reaction device is decarburization reaction bin, and decarburization catalyst is loaded in the decarburization reaction bin.

[0008] Preferably, the decarburization reaction bin is provided with multiple in parallel.

[0009] Preferably, the heat exchange device is reflux pipeline connected between external discharge pipeline and intake pipeline, and part of flue gas after decarburization is inserted into mixed gas in intake pipeline by reflux pipeline, to further improve the temperature of mixed gas.

[0010] Preferably, the heat exchange device is gas-gas heat exchanger, for heat exchange between flue gas after decarburization in exhaust pipeline and flue gas in intake pipeline.

[0011] Preferably, gas straight-through pipeline is equipped between the outlet of denitration reaction device and the inlet of gas-gas heat exchanger.

[0012] Preferably, pipeline auxiliary line directly connected with chimney is equipped on exhaust pipeline before the inlet of gas-gas heat exchanger.

[0013] The flue gas denitration system of the utility model utilizes the heat generated by flue gas decarbonization as a heat source, raises the temperature of denitration flue gas, greatly reduces the consumption of heat sources such as steam, realizes low-consumption denitration, reduces the flue gas denitration cost, simultaneously reduces the carbon monoxide content in flue gas, and reduces environmental pollution. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a schematic view of the first embodiment of the flue gas denitration system of the utility model.

[0015] Figure 2 It is a schematic view of the second embodiment of the flue gas denitration system of the utility model.

[0016] In the drawing: air inlet pipeline 1, heating device 2, air inlet pipeline 3, ammonia injection device 4, temperature measuring point 5, denitration reaction device 6, decarbonization reaction device 7, gas straight-through pipeline 8, exhaust pipeline 9, gas-gas heat exchanger 10, backflow pipeline 11, pipeline auxiliary line 12, chimney 13. DETAILED DESCRIPTION

[0017] In order to better understand the purpose, structure and function of the utility model, the flue gas denitration system of the utility model will be further described in detail below in combination with the drawings.

[0018] Figure 1 An embodiment of the flue gas denitration system of the utility model is shown, wherein the flue gas denitration device comprises air inlet pipeline 3, exhaust pipeline 9 and chimney 13, the main body of air inlet pipeline 3 is arranged from bottom to top along the gas flow direction, the exhaust pipeline 9 is arranged downwardly and in parallel with air inlet pipeline 3, heating device 2 is arranged at the inlet of air inlet pipeline 3, ammonia injection device 4 is arranged at the upper part of air inlet pipeline 3, denitration reaction device 6 is connected to air inlet pipeline 3 after ammonia injection device 4, the gas outlet of denitration reaction device 6 is connected to decarbonization reaction device 7, decarbonization reaction device 7 is connected to exhaust pipeline 9, and heat exchange device for exchanging heat with air inlet pipeline 3 is arranged on exhaust pipeline 9. Flue gas first enters heating device 2, the heat source can be selected from steam, natural gas or electric heating; after being heated by the heat source, the flue gas enters air inlet pipeline 3 to mix with ammonia gas to obtain mixed gas, the mixed gas enters denitration reaction device 6 to perform denitration reaction, after the reaction, the denitrated flue gas enters decarbonization reaction device 7 to perform decarbonization reaction, after the reaction, the decarbonized flue gas enters heat exchange device to exchange heat with the flue gas in air inlet pipeline 3, and the heat-exchanged flue gas is exhausted by exhaust pipeline 9.

[0019] The decarburization reaction device 7 is a decarburization reaction chamber, the gas inlet of the reaction chamber is connected with the gas outlet of the denitration reaction device 6, the gas outlet of the reaction chamber is connected with the exhaust pipeline 9, and the decarburization reaction chamber is provided with a decarburization catalyst, such as a noble metal decarburization catalyst like gold, platinum and palladium or a non-noble metal catalyst like copper and manganese.

[0020] The ammonia injection device 4 is further provided with a temperature measuring point 5 on the gas inlet pipeline 3, which is used for detecting the temperature of the mixed gas entering the denitration reaction device 6, and the temperature of the mixed gas is controlled to be 180-350 DEG C.

[0021] As shown in the figure, Figure 1 The heat exchange device is a reflux pipeline 11 connected between the exhaust pipeline 9 and the gas inlet pipeline 3, and the flue gas after partial decarburization is introduced into the gas inlet pipeline 3 through the reflux pipeline 11, so as to further increase the temperature of the mixed gas, and preferably, the reflux pipeline 11 is further provided with a control valve or a fan to control the amount of flue gas introduced back.

[0022] The decarburization reaction chamber is provided with a plurality of chambers in parallel, which can switch the decarburization reaction chamber and replace the deactivated decarburization catalyst under the normal operation of the denitration system, so as to realize the long-period stable operation of the denitration system.

[0023] Figure 2 The second embodiment of the flue gas denitration system of the utility model is shown, the heat exchange device is a gas-gas heat exchanger 10, the flue gas in the exhaust pipeline 9 is introduced into the gas-gas heat exchanger 10 and exchanges heat with the flue gas in the gas inlet pipeline 3, so as to further increase the temperature thereof. The gas-gas heat exchanger 10 is a plate heat exchanger. In other embodiments of the utility model, the gas-gas heat exchanger 10 can also select a tube heat exchanger.

[0024] The gas straight-through pipeline 8 is arranged between the gas outlet of the denitration reaction device 6 and the gas inlet of the gas-gas heat exchanger 10, so that the flue gas after denitration can directly enter the gas-gas heat exchanger 10 without passing through the decarburization reaction chamber; when the temperature of the mixed gas entering the denitration reaction device 6 is too high, the gas straight-through pipeline 8 can be appropriately opened to reduce the amount of gas entering the decarburization reaction chamber, so that the temperature of the flue gas after decarburization is reduced, and then the temperature of the mixed gas entering the denitration reaction device 6 is reduced; in other embodiments of the utility model, the pipeline auxiliary line 12 directly connected with the chimney 13 can be arranged on the exhaust pipeline 9 before the gas inlet of the gas-gas heat exchanger 10, and when the temperature of the mixed gas is too high, the pipeline auxiliary line 12 can be appropriately opened to reduce the amount of gas entering the gas-gas heat exchanger 10, so as to reduce the temperature of the mixed gas.

[0025] When the flue gas denitration system is put into production and operation, the flue gas first enters the heating device 2, is heated by the heat source, enters the gas inlet pipeline 3 and is mixed with ammonia to obtain mixed gas, the temperature of the mixed gas is controlled between 180-350 DEG C, the mixed gas enters the denitration reaction device 6 for denitration reaction from the gas inlet pipeline 3, after denitration, the denitrified flue gas enters the decarbonization reaction bin and is catalyzed by the decarbonization catalyst to carry out decarbonization reaction, the temperature of the decarbonized flue gas is increased to 400 DEG C or more, the decarbonized flue gas is heat exchanged with the flue gas in the gas inlet pipeline 3 through the heat exchange device, the temperature of the mixed gas is further increased, the heat exchanged flue gas is discharged outside the chimney 13, according to the temperature change of the mixed gas entering the denitration reaction device 6, the heating device 2 is gradually closed, when the temperature of the mixed gas is too high, the temperature of the mixed gas can be regulated and controlled by adjusting the gas inlet amount of the heat exchange device.

[0026] The flue gas denitration system can utilize the heat generated by flue gas decarbonization as a heat source to heat and increase the temperature of denitration flue gas, so as to reduce the consumption of heat sources such as steam and natural gas, realize low-consumption denitration, and reduce denitration cost.

[0027] It can be understood that the utility model is described through some embodiments, and those skilled in the art know that various changes or equivalent replacements can be made to these features and embodiments without departing from the spirit and scope of the utility model.In addition, under the guidance of the utility model, these features and embodiments can be modified to adapt to specific conditions and materials without departing from the spirit and scope of the utility model.Therefore, the utility model is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present application belong to the scope protected by the utility model.

Claims

1. A flue gas denitration system comprising an air inlet duct (3), an air outlet duct (9), a chimney (13), characterized in that, The air inlet pipeline (3) is arranged upward along the gas flow direction, the air outlet pipeline (9) is arranged downward and parallel to the air inlet pipeline (3), the air inlet pipeline (3) is provided with a heating device (2) at the inlet, the upper pipeline of the air inlet pipeline (3) is provided with an ammonia injection device (4), the air inlet pipeline (3) after the ammonia injection device (4) is connected downward with a denitration reaction device (6), the denitration reaction device (6) is connected with a decarbonization reaction device (7) at the outlet, the decarbonization reaction device (7) is connected with the air outlet pipeline (9) at the outlet, and the air outlet pipeline (9) is provided with a heat exchange device for heat exchange with the air inlet pipeline (3).

2. The flue gas denitration system according to claim 1, characterized by, The air inlet pipeline (3) after the ammonia injection device (4) is provided with a temperature measuring point (5).

3. The flue gas denitration system according to claim 2, characterized by, The decarbonization reaction device (7) is a decarbonization reaction bin, and the decarbonization reaction bin is provided with a decarbonization catalyst.

4. The flue gas denitration system according to claim 3, characterized by, The decarbonization reaction bin is provided with a plurality of parallel connection.

5. The flue gas denitration system according to claim 4, wherein The heat exchange device is a backflow pipeline (11) connected between the air outlet pipeline (9) and the air inlet pipeline (3).

6. The flue gas denitration system according to claim 4, wherein The heat exchange device is a gas-gas heat exchanger (10) for heat exchange between the flue gas in the air outlet pipeline (9) after decarbonization and the flue gas in the air inlet pipeline (3).

7. The flue gas denitration system according to claim 6, characterized by, The gas-gas heat exchanger (10) is provided with a gas straight-through pipeline (8) between the outlet of the denitration reaction device (6) and the inlet.

8. The flue gas denitration system according to claim 6, characterized by, The air outlet pipeline (9) before the inlet of the gas-gas heat exchanger (10) is provided with a pipeline branch line (12) directly connected with a chimney (13).

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