SCR (Selective Catalytic Reduction) denitration system and ammonia-air mixing device thereof

Abstract

The utility model relates to the technical field of flue gas denitration, in particular to an SCR (Selective Catalytic Reduction) denitration system and an ammonia-air mixing device thereof, the SCR denitration system comprises an ammonia-air mixer and an air preheater, and the ammonia-air mixer is externally connected with an ammonia gas storage tank for providing ammonia gas for the ammonia-air mixer; the ammonia-air mixer is externally connected with a hot air pipeline for providing hot air for the ammonia-air mixer, and the hot air pipeline is connected with an air preheater for providing hot air for the hot air pipeline; the system comprises a flue system, and an upper-level economizer, an ammonia spraying grid, an SCR module, a lower-level economizer, an air preheater and a condensate water heater are sequentially arranged in the flue system in the flowing direction of flue gas. According to the SCR denitration system and the ammonia-air mixing device thereof provided by the utility model, air used by the ammonia-air mixer is replaced by hot air, so that the condensate water phenomenon of the ammonia-air mixing device is reduced, the mixing effect of ammonia gas and air is improved, and the working efficiency of SCR denitration is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas denitration, in particular to an SCR denitration system and an ammonia-air mixing device thereof. Background Art

[0002] In the work of controlling air pollution, it is very important to control the emission of industrial waste gas. At present, my country generally adopts SCR selective catalytic reduction denitrification technology to treat industrial waste gas to remove the content of harmful gases such as nitrogen oxides and sulfides in the waste gas. SCR denitrification technology uses ammonia and air mixed gas to react with harmful gases such as nitrogen oxides in flue gas under the action of a catalyst to reduce the content of harmful gases, in which ammonia and air mixed gas is prepared by an ammonia-air mixing device.

[0003] At present, ammonia-air mixing devices usually use room temperature air and ammonia to prepare ammonia-air mixed gas. When ammonia expands, it is easy to condense the air to form condensed water, thus causing blockage of the air duct, affecting the mixing effect of ammonia and air, and ultimately affecting the efficiency of SCR denitrification. Utility Model Content

[0004] In view of the defects existing in the prior art, the utility model provides an SCR denitrification system and an ammonia-air mixing device thereof, which replaces the air used by the ammonia-air mixer with hot air, thereby reducing the condensation water phenomenon of the ammonia-air mixing device, improving the mixing effect of ammonia and air, and improving the working efficiency of SCR denitrification.

[0005] In order to solve the above technical problems, the utility model is solved by the following technical solutions:

[0006] An ammonia-air mixing device comprises an ammonia-air mixer and an air preheater. The ammonia-air mixer is externally connected to an ammonia storage tank for supplying ammonia to the ammonia-air mixer; the ammonia-air mixer is externally connected to a hot air duct for supplying hot air to the ammonia-air mixer, and the hot air duct is connected to the air preheater for supplying hot air to the hot air duct.

[0007] In the utility model, an ammonia storage tank provides ammonia to the ammonia-air mixer, and the hot air heated by the air preheater enters the ammonia-air mixer through the hot air duct, and the hot air and ammonia are mixed in the ammonia-air mixer to form an ammonia-air mixed gas.

[0008] The hot air duct connected to the air preheater is arranged so that the ammonia gas is mixed with the hot air, thereby weakening the condensation phenomenon caused by the expansion process of the ammonia gas.

[0009] Preferably, a stop valve is provided on the hot air duct.

[0010] In the utility model, the air flow rate in the hot air duct is controlled by arranging a stop valve.

[0011] Preferably, a check valve is provided on the hot air duct.

[0012] In the utility model, the air flow direction in the hot air duct is controlled by arranging a check valve, so as to ensure that the hot air flows from the air preheater to the ammonia-air mixer in the hot air duct.

[0013] Preferably, the ammonia storage tank is connected to the ammonia-air mixer via an ammonia inlet pipe, and ammonia is input into the ammonia-air mixer via the ammonia inlet pipe.

[0014] In the utility model, ammonia in the ammonia storage tank enters the ammonia-air mixer through the ammonia inlet pipe.

[0015] A denitrification system, comprising any of the above-mentioned ammonia-air mixing devices, including a flue system, in which an upper economizer, an ammonia injection grid, an SCR module, a lower economizer, an air preheater and a condensate heater are arranged in sequence along the flue gas flow direction.

[0016] In the utility model, in the SCR denitration system, the flue gas in the flue system passes through the upper economizer, the ammonia injection grid, the SCR module, the lower economizer, the air preheater and the condensate heater in sequence, and finally obtains the denitration flue gas after the denitration treatment.

[0017] Preferably, the ammonia injection grid is connected to the ammonia-air mixer via a mixed gas output pipe, and the ammonia-air mixer provides ammonia and air mixed gas to the ammonia injection grid via the mixed gas output pipe.

[0018] In the utility model, the mixed gas output pipe is arranged to transport the mixed gas of ammonia and air prepared by the ammonia-air mixer into the flue system, and the mixed gas of ammonia and air is sprayed into the flue system through the ammonia spraying grid.

[0019] Preferably, the spray head of the ammonia spray grid faces the SCR module and the ammonia and air mixed gas is evenly sprayed toward the SCR module through the spray head.

[0020] In the utility model, the ammonia spraying grid is arranged so that the ammonia gas and the air mixed gas can be sprayed evenly toward the SCR module, which is helpful for the reduction reaction to proceed fully. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the SCR denitration system and its ammonia-air mixing device in Example 1; DETAILED DESCRIPTION

[0022] In order to further understand the content of the utility model, the utility model is described in detail in conjunction with the accompanying drawings and embodiments. It should be understood that the embodiments are only used to explain the utility model but not to limit it.

[0023] Example 1

[0024] like Figure 1 As shown, this embodiment provides an ammonia-air mixing device, which includes an ammonia-air mixer 120 and an air preheater 180. The ammonia-air mixer 120 is externally connected to an ammonia storage tank 110 for providing ammonia to the ammonia-air mixer 120; the ammonia-air mixer 120 is externally connected to a hot air duct 130 for providing hot air to the ammonia-air mixer 120, and the hot air duct 130 is connected to the air preheater 180 for providing hot air to the hot air duct 130.

[0025] Through this embodiment, the ammonia storage tank 110 provides ammonia to the ammonia-air mixer 120, and the hot air heated by the air preheater 180 enters the ammonia-air mixer 120 through the hot air duct 130. The hot air and ammonia are mixed in the ammonia-air mixer 120 to form an ammonia-air mixed gas, wherein the air preheater 180 provides hot air to the ammonia-air mixer 120 through the hot air duct 130, so that the ammonia is mixed with the hot air, thereby reducing the condensation phenomenon caused by the expansion process of the ammonia.

[0026] In this embodiment, a stop valve 131 is provided on the hot air duct 130 .

[0027] The stop valve 131 provided in this embodiment is used to control the air flow rate in the hot air duct 130 .

[0028] In this embodiment, a check valve 132 is provided on the hot air duct 130 .

[0029] The check valve 132 provided in this embodiment is used to control the air flow direction in the hot air duct 130 to ensure that the hot air flows from the air preheater 180 to the ammonia-air mixer 120 in the hot air duct 130 .

[0030] In this embodiment, the ammonia storage tank 110 is connected to the ammonia-air mixer 120 through the ammonia input pipe 111 , and ammonia is input into the ammonia-air mixer 120 through the ammonia input pipe 111 .

[0031] According to this embodiment, the ammonia in the ammonia storage tank 110 enters the ammonia-air mixer 120 through the ammonia inlet pipe 111 .

[0032] like Figure 1As shown, the present embodiment further provides an SCR denitrification system, which includes any of the above-mentioned ammonia-air mixing devices, including a flue system 100, in which an upper economizer 140, an ammonia injection grid 150, an SCR module 160, a lower economizer 170, an air preheater 180 and a condensate heater 190 are sequentially arranged along the flue gas flow direction in the flue system 100.

[0033] Through this embodiment, in the SCR denitrification system, the flue gas in the flue system 100 passes through the upper economizer 140, the ammonia injection grid 150, the SCR module 160, the lower economizer 170, the air preheater 180 and the condensate heater 190 in sequence, and finally obtains the denitrified flue gas after denitrification treatment.

[0034] In this embodiment, the ammonia injection grid 150 is connected to the ammonia-air mixer 120 via the mixed gas output pipe 121 , and the ammonia-air mixer 120 provides ammonia and air mixed gas to the ammonia injection grid 150 via the mixed gas output pipe 121 .

[0035] By setting the mixed gas output pipe 121 in this embodiment, the ammonia-air mixed gas prepared by the ammonia-air mixer 120 is transported into the flue system 100 , and the ammonia-air mixed gas is sprayed into the flue system 100 through the ammonia spray grid 150 .

[0036] In this embodiment, the spray head of the ammonia spray grid 150 faces the SCR module 160 and sprays the ammonia gas and the air mixture gas uniformly toward the SCR module 160 through the spray head.

[0037] By disposing the ammonia spray grid 150 in this embodiment, the ammonia and air mixed gas can be evenly sprayed toward the SCR module, which helps the reduction reaction to proceed fully.

[0038] In short, the above is only a preferred embodiment of the present utility model, and all equivalent changes and modifications made according to the scope of the patent application of the present utility model should fall within the scope of the present utility model patent.

Claims

1. An ammonia-air mixing device, characterized in that: The invention comprises an ammonia-air mixer (120) and an air preheater (180); the ammonia-air mixer (120) is externally connected to an ammonia storage tank (110) for supplying ammonia to the ammonia-air mixer (120); the ammonia-air mixer (120) is externally connected to a hot air duct (130) for supplying hot air to the ammonia-air mixer (120); the hot air duct (130) is connected to the air preheater (180) for supplying hot air to the hot air duct (130).

2. The ammonia-air mixing device according to claim 1, characterized in that: A stop valve (131) is provided on the hot air duct (130).

3. The ammonia-air mixing device according to claim 1, characterized in that: A check valve (132) is provided on the hot air duct (130).

4. The ammonia-air mixing device according to claim 1, characterized in that: The ammonia storage tank (110) is connected to the ammonia-air mixer (120) via an ammonia input pipe (111), and ammonia is input into the ammonia-air mixer (120) via the ammonia input pipe (111).

5. An SCR denitration system, characterized in that: It comprises an ammonia-air mixing device as described in any one of claims 1-4.

6. The SCR denitration system according to claim 5, characterized in that: The invention comprises a flue system (100), wherein an upper economizer (140), an ammonia injection grid (150), an SCR module (160), a lower economizer (170), an air preheater (180) and a condensate heater (190) are sequentially arranged in the flue system (100) along the direction of flue gas flow.

7. The SCR denitration system according to claim 6, characterized in that: The ammonia spray grid (150) is connected to the ammonia-air mixer (120) via the mixed gas output pipe (121), and the ammonia-air mixer (120) provides ammonia and air mixed gas to the ammonia spray grid (150) via the mixed gas output pipe (121).

8. The SCR denitration system according to claim 6, characterized in that: The spray head of the ammonia spray grid (150) faces the SCR module (160) and sprays the ammonia gas and air mixed gas uniformly toward the SCR module (160) through the spray head.

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