CN211586033U

CN211586033U - Boiler flue gas denitration device

Info

Publication number: CN211586033U
Application number: CN202020093245.4U
Authority: CN
Inventors: 徐志坚; 杨乐恩; 刘海滨; 田超; 纪涛; 杨化明; 徐庆国; 杨道晓
Original assignee: Sunvision Sweet Co ltd
Current assignee: Sunvision Sweet Co ltd
Priority date: 2020-01-16
Filing date: 2020-01-16
Publication date: 2020-09-29
Anticipated expiration: 2030-01-16

Abstract

The utility model relates to a boiler flue gas denitration device, which comprises an ammonia tank; the ammonia water tank is connected with the hearth through a first ammonia water pipeline; the top of the hearth is connected with the top of the catalytic reactor through a flue gas pipeline; the ammonia water tank is also connected with the upper part of the ammonia water evaporator through a second ammonia water pipeline, and the top of the ammonia water evaporator is connected with a distributor in the catalytic reactor; the upper part of the catalytic reactor is provided with a high-temperature coal economizer, the lower part of the catalytic reactor is provided with a catalyst layer, the catalyst layer consists of 5 groups of honeycomb catalysts, and the interval between the honeycomb catalysts is 0.3-0.5 m; and a flue gas outlet is formed in the bottom of the catalytic reactor. The utility model discloses possible SCR + SNCR joint denitration, can also be according to the nimble use of nitrogen oxide's in the flue gas content, carry out SCR or SNCR denitration alone, practice thrift the aqueous ammonia quantity.

Description

Boiler flue gas denitration device

Technical Field

The utility model relates to a flue gas denitration technical field especially relates to a boiler flue gas denitration device.

Background

The nitrogen oxides are gaseous pollutants which have a large influence in the atmospheric pollutants, the nitrogen oxides can cause photochemical reaction under the action of sunlight to form photochemical smog, so that serious atmospheric pollution is caused, and the problem of NOx emission is more and more concerned with the increasing strictness of environmental requirements. The nitrogen oxides are mainly derived from the combustion process of fossil fuels such as coal, petroleum and the like and the smoke emission in the roasting and smelting processes of ores, wherein the smoke discharged by various combustion boilers, particularly boilers of thermal power plants, has the characteristics of low concentration, large smoke quantity, much floating dust and the like and is difficult to treat.

In the industrial flue gas denitration project, the determination of a process device and the selection of a reducing agent are important. At present, denitration technologies including catalytic reduction SCR method, non-catalytic reduction SNCR method and other process devices are commonly adopted; liquid ammonia, urea and ammonia are generally used as the reducing agent. The SCR method and the SNCR method respectively have advantages and disadvantages, wherein the SCR technology is to carry out reduction reaction on a reducing agent and NOX in flue gas to remove nitrogen oxide under the action of a catalyst, and has the advantages of high denitration reaction efficiency and stable system operation, and the disadvantages of high one-time investment and large occupied area; the SNCR technology is to directly spray a reducing agent into a high-temperature area of a hearth for direct reduction reaction, has the advantages of low investment, simple operation and management and the like, and has the main defects of low denitration efficiency, unstable denitration efficiency and the like. Therefore, at present, the SCR and SNCR combined denitration reactor is frequently used to reduce the discharge amount of nitrogen oxides, but the consumption amount of ammonia water is large. Therefore, a flue gas denitration device which can be flexibly used according to the emission condition of nitrogen oxides is needed.

SUMMERY OF THE UTILITY MODEL

The utility model discloses to prior art's not enough, provide a boiler flue gas denitrification facility. Not only can reduce the nitrogen oxide emission, still can use according to the nitrogen oxide circumstances of discharging and nimble, carry out SCR or SNCR denitration alone, practice thrift the aqueous ammonia quantity.

The utility model discloses a realize through following technical scheme:

the utility model provides a boiler flue gas denitration device, which comprises an ammonia water tank; the ammonia water tank is connected with an ammonia water spray gun in the hearth through a first ammonia water pipeline; the top of the hearth is connected with the top of the catalytic reactor through a flue gas pipeline;

the ammonia water tank is also connected with the upper part of the ammonia water evaporator through a second ammonia water pipeline, and the top of the ammonia water evaporator is connected with a distributor arranged in the catalytic reactor; the lower part of the ammonia water evaporator is connected with a dilution fan; the upper part of the catalytic reactor is provided with a high-temperature coal economizer, the lower part of the catalytic reactor is provided with a catalyst layer, the catalyst layer consists of 5 groups of honeycomb catalysts, and the interval between the honeycomb catalysts is 0.3-0.5 m; the distributor is positioned between the high-temperature economizer and the catalyst layer, and the bottom of the catalytic reactor is provided with a flue gas outlet.

Preferably, a first valve is arranged on the first ammonia water pipeline. The mass concentration of the ammonia water is 20%, and according to the content of nitrogen oxides discharged from the boiler, the first valve and the second valve can be controlled to determine whether SNCR denitration or SCR denitration is used, or SCR + SNCR combined denitration is used.

Preferably, a second valve is arranged on the second ammonia water pipeline. The second ammonia water pipeline is connected with the ammonia water evaporator, after ammonia water enters the ammonia water evaporator, hot air sent by the dilution fan heats the ammonia water in the ammonia water evaporator to about 200 ℃ for gasification and dilution, and then the gasified and diluted ammonia water enters the distributor from the ammonia water evaporator through wind power and is sprayed out from nozzles on the distributor. The connecting pipeline of the distributor and the ammonia evaporator is very thin, and the amount of the gasified and diluted ammonia water entering the catalytic reactor is controlled to prevent the waste of the ammonia water. The reaction temperature in the catalytic reactor is controlled between 280 ℃ and 420 ℃, and the catalyst is damaged due to the overhigh temperature.

Preferably, the ammonia water spray gun consists of four groups of ammonia water spray heads which are arranged side by side. The four groups of ammonia water spray heads are all spray heads, and sprayed ammonia water is in a fog shape, so that the contact surface of the ammonia water and nitrogen oxides is increased, and the reduction of the nitrogen oxides is facilitated.

Preferably, a hearth burner is further arranged in the hearth. The temperature in the hearth is controlled between 850 ℃ and 1100 ℃, and the optimal reduction temperature is 900 ℃, so that the ammonia water is favorably utilized. At too high a temperature, the ammonia is oxidized to nitrogen oxides.

Preferably, the ammonia water spray gun is positioned 3 meters above the hearth burner. The distance between the ammonia water spray gun and the hearth burner is controlled, so that the treatment of the ammonia water on the nitrogen oxide is facilitated.

Preferably, a flue gas dust remover is arranged on the flue gas pipeline. The flue gas dust remover can effectively remove dust in the flue gas after SNCR denitration, and filters the flue gas.

Preferably, a plurality of nozzles are arranged on the distributor.

The utility model has the advantages that:

1. the utility model discloses possible SCR + SNCR joint denitration, can also be according to the nimble use of the content of oxide in the flue gas, carry out SCR or SNCR denitration alone, practice thrift the aqueous ammonia quantity.

2. The utility model discloses nimble the use has still reduced the catalyst quantity, and the catalyst layer comprises 5 honeycomb formula catalysts of group, interval between the honeycomb formula catalyst is 0.3 ~ 0.5m, and the flue gas both can be very smooth and easy pass through the catalyst layer like this, can also increase the treatment effeciency of flue gas. The cost is saved.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic structural view of an ammonia water lance;

shown in the figure:

1. ammonia tank, 2, furnace, 3, catalytic reactor, 4, ammonia evaporator, 5, first ammonia pipeline, 6, second ammonia pipeline, 7, first valve, 8, second valve, 9, ammonia spray gun, 10, distributor, 11, dilution fan, 12, flue gas pipeline, 13, high temperature economizer, 14, catalyst layer, 15, flue gas dust remover, 16, furnace combustor, 17, flue gas discharge port.

Detailed Description

In order to clearly illustrate the technical features of the present solution, the present solution is explained below by way of specific embodiments.

As shown in fig. 1 and 2, the utility model provides a boiler flue gas denitration device, which comprises an ammonia tank 1; the ammonia water tank 1 is connected with an ammonia water spray gun 9 in the hearth 2 through a first ammonia water pipe 5; the top of the hearth 8 is connected with the top of the catalytic reactor 3 through a flue gas pipeline 12;

the ammonia water tank 1 is also connected with the upper part of an ammonia water evaporator 4 through a second ammonia water pipeline 6, and the top of the ammonia water evaporator 4 is connected with a distributor 10 arranged in the catalytic reactor 3; the lower part of the ammonia water evaporator 4 is connected with a dilution fan 11; the upper part of the catalytic reactor 3 is provided with a high-temperature coal economizer 13, the lower part of the catalytic reactor is provided with a catalyst layer 14, the catalyst layer 14 consists of 5 groups of honeycomb catalysts, and the interval between the honeycomb catalysts is 0.3-0.5 m; the distributor 10 is positioned between the high-temperature economizer 13 and the catalyst layer 14, and the bottom of the catalytic reactor 3 is provided with a flue gas outlet 17.

And a first valve 7 is arranged on the first ammonia water pipeline 5. And a second valve 8 is arranged on the second ammonia water pipeline 6. The ammonia water spray gun 9 is composed of four groups of ammonia water spray heads which are arranged side by side. And a hearth combustor 16 is also arranged in the hearth 2. The ammonia water spray gun 9 is positioned 3 meters above the hearth combustor 16. And a flue gas dust remover 15 is arranged on the flue gas pipeline 12. A plurality of nozzles are arranged on the distributor 10.

Example 1: SNCR denitration

When nitrogen oxide content is less in the boiler flue gas, open first valve 7, the aqueous ammonia gets into first aqueous ammonia pipeline 5, from the 9 blowout of aqueous ammonia spray gun, forms the aqueous ammonia spraying in furnace 2, carries out denitration treatment to the flue gas that contains nitrogen oxide in furnace 2, and flue gas after the denitration treatment passes through flue gas pipeline 12 and gets into flue gas dust remover 15 and filter the flue gas. The filtered flue gas enters the catalytic reactor 3 through the flue gas pipeline 12 and is discharged from a flue gas outlet 17 at the bottom of the catalytic reactor 3, so that the denitration of the boiler flue gas is completed.

Example 2: SCR denitration

When the content of nitrogen oxides in the boiler flue gas is high, the second valve 8 is opened, the ammonia water enters the ammonia water evaporator 4 through the second ammonia water pipeline 6, the dilution fan 11 is opened simultaneously, heated hot air is blown into the ammonia water evaporator 4, the ammonia water in the ammonia water evaporator 4 is heated to 200 ℃ by the hot air to be gasified and diluted, the gasified and diluted ammonia water is blown into the catalytic reactor 3 through the distributor 10, and the gasified and diluted ammonia water is sprayed into the catalyst layer 14 through the distributor 10. The flue gas is discharged into the flue gas channel from the hearth 2, particulate matters in the flue gas are filtered by the flue gas dust remover 15, and then the flue gas enters the catalytic reactor 3. In the catalytic reactor 3, the filtered flue gas firstly passes through the high-temperature economizer 13 and then enters the catalyst layer 14, the nitrogen oxides in the flue gas and the ammonia water in the catalyst layer 14 undergo catalytic reduction reaction, most of the nitrogen oxides in the reacted flue gas are changed into nitrogen, and the nitrogen is discharged from a flue gas outlet 17 at the bottom of the catalytic reactor 3, so that the denitration of the boiler flue gas is completed.

Example 3: SCR + SNCR combined denitration

When the content of nitrogen oxides in boiler flue gas is very large, a first valve 7 and a second valve 8 are opened simultaneously, ammonia water enters a first ammonia water pipeline 5 and a second ammonia water pipeline 6 from an ammonia water tank 1, the ammonia water in the first ammonia water pipeline 5 is sprayed above a hearth combustor 16 in a hearth 2 through an ammonia water spray gun 9, the ammonia water is sprayed in the form of ammonia water spray to carry out denitration treatment on the flue gas in the hearth 2, the flue gas after denitration treatment enters a flue gas dust remover 15 from the top of the hearth 2 through a flue gas pipeline 12 to filter the flue gas, particulate matters in the flue gas are filtered, and then the flue gas enters a catalytic reactor 3 from the top of the catalytic reactor 3; meanwhile, ammonia water enters the ammonia water evaporator 4 through the second ammonia water pipeline 6, heated hot air is blown into the ammonia water evaporator 4 by the dilution fan 11, the ammonia water in the ammonia water evaporator 4 is heated to 200 ℃ by the hot air to be gasified and diluted, the gasified and diluted ammonia water is blown into the catalytic reactor 3, and the gasified and diluted ammonia water is sprayed into the catalyst layer 14 through the distributor 10. The filtered flue gas firstly passes through the high-temperature economizer 13 and then enters the catalyst layer 14, nitrogen oxides in the flue gas and ammonia water in the catalyst layer 14 are subjected to catalytic reduction reaction, most of nitrogen oxides in the reacted flue gas are changed into nitrogen, and the nitrogen is discharged from a flue gas outlet 17 at the bottom of the catalytic reactor 3, so that denitration of the boiler flue gas is completed.

Through continuous on-line detection, the content of nitrogen oxides in the flue gas discharged by the embodiments 1-3 is lower than 50mg/NM³。

When the content of nitrogen oxides in the boiler flue gas is low, the amount of ammonia water is saved by 60% by using the SNCR denitration of the embodiment 1 compared with the existing SCR + SNCR combined denitration;

when the content of nitrogen oxides in the boiler flue gas is high, the use amount of ammonia water is saved by 40% by using the SCR denitration of the embodiment 2 compared with the existing SCR + SNCR combined denitration;

when the content of nitrogen oxides in the boiler flue gas is very large, the ammonia water consumption is saved by 10% by using the SCR + SNCR combined denitration of the embodiment 3 compared with the existing SCR + SNCR combined denitration.

Of course, the above description is not limited to the above examples, and technical features of the present invention that are not described in the present application may be implemented by or using the prior art, and are not described herein again; the above embodiments and drawings are only used for illustrating the technical solutions of the present invention and are not intended to limit the present invention, and the present invention has been described in detail with reference to the preferred embodiments, and those skilled in the art should understand that changes, modifications, additions or substitutions made by those skilled in the art within the spirit of the present invention should also belong to the protection scope of the claims of the present invention.

Claims

1. The utility model provides a boiler flue gas denitrification facility which characterized in that: the device comprises an ammonia water tank; the ammonia water tank is connected with an ammonia water spray gun in the hearth through a first ammonia water pipeline; the top of the hearth is connected with the top of the catalytic reactor through a flue gas pipeline;

2. The boiler flue gas denitration device according to claim 1, characterized in that: and a first valve is arranged on the first ammonia water pipeline.

3. The boiler flue gas denitration device according to claim 1, characterized in that: and a second valve is arranged on the second ammonia water pipeline.

4. The boiler flue gas denitration device according to claim 1, characterized in that: the ammonia water spray gun consists of four groups of ammonia water spray heads which are arranged side by side.

5. The boiler flue gas denitration device according to claim 1, characterized in that: and a hearth combustor is also arranged in the hearth.

6. The boiler flue gas denitration device according to claim 5, characterized in that: the ammonia water spray gun is positioned 3 meters above the hearth combustor.

7. The boiler flue gas denitration device according to claim 1, characterized in that: and a flue gas dust remover is arranged on the flue gas pipeline.

8. The boiler flue gas denitration device according to claim 1, characterized in that: the distributor is provided with a plurality of nozzles.