SNCR (selective non-catalytic reduction) and SCR (selective catalytic reduction) combined water heater denitration system

Abstract

The SNCR and SCR combined water heater denitration system is adopted. Due to the fact that the temperature of an outlet of a water heater is low, a urea solution cannot be completely decomposed and coagulated into blocks, operation of denitration is affected, and the ultra-low emission standard is difficult to reach. The device comprises a boiler (12), a plurality of spray guns (7) mounted on the boiler, a gas conveying system and an ammonia water conveying system, a main conveying pipe (6) of the ammonia water conveying system is connected to main spray cavities of the spray guns, a gas conveying pipe (11) of the gas conveying system is divided into two paths, one path is communicated with the main spray cavities of the spray guns, and the other path is communicated with the main spray cavities of the spray guns. And the other path is communicated with the cooling cavity of the spray gun. The denitration device is used for denitration of the water heater.

Description

Technical Field

[0001] The utility model relates to a hot water boiler denitration system adopting a SNCR+SCR combination. Background Art

[0002] The hot water boiler denitrification system uses urea as the raw material, sets up a urea storage tank, and pumps it to a spray gun to spray it into the boiler for denitrification. Due to the low outlet temperature of the hot water boiler, the urea solution cannot be completely decomposed and condenses into blocks, affecting the operation of denitrification and making it difficult to meet ultra-low emission standards. At the same time, when the denitrification system exits, the temperature of the urea solution delivery pipeline drops, causing the urea solution attached to the pipe wall to crystallize into blocks, which will cause pipeline blockage over a long period of time. Utility Model Content

[0003] The purpose of the utility model is to solve the above-mentioned problems and provide a hot water boiler denitration system using a combination of SNCR+SCR.

[0004] The above purpose is achieved through the following technical solutions:

[0005] A hot water boiler denitrification system using a combination of SNCR+SCR, comprising: a boiler, a plurality of spray guns installed on the boiler, a gas transmission system and an ammonia water transmission system, wherein the main transmission pipe of the ammonia water transmission system is connected to the main spray chamber of the spray gun, and the gas transmission pipe of the gas transmission system is divided into two paths, one of which is connected to the main spray chamber of the spray gun, and the other is connected to the cooling chamber of the spray gun.

[0006] The hot water boiler denitrification system adopts a combined SNCR+SCR, and the gas transmission system includes an air compressor and a cold dryer. The air compressor is connected to the cold dryer through a pipeline, and the cold dryer is connected to the gas storage tank through a pipeline. The outlet of the gas storage tank is connected to the gas transmission pipe.

[0007] The described hot water boiler denitrification system adopts the SNCR+SCR combination, and the described ammonia water delivery system includes an ammonia water storage tank, and the outlet of the ammonia water storage tank is connected to two delivery pipelines, and the two delivery pipelines are connected in parallel to the described main delivery pipe.

[0008] The hot water boiler denitrification system adopting the SNCR+SCR combination, the delivery pipeline includes a delivery branch pipe, and the delivery branch pipe is equipped with a delivery pump and a valve.

[0009] The hot water boiler denitration system adopts the SNCR+SCR combination, and two layers of denitration catalysts are installed in the tail flue of the boiler. Beneficial Effects

[0010] 1. The utility model uses ammonia water as a denitration reducing agent, which can improve the denitration effect and prevent crystallization when the temperature of the exit pipe of the denitration system drops, thereby preventing the operation of the denitration system from being affected.

[0011] 2. The utility model provides an air delivery system, which can mix the compressed air with the ammonia water after delivery to the spray gun, so that it is sprayed in a mist form, thereby ensuring the denitrification reduction effect.

[0012] 3. One of the compressed air paths of the utility model is connected to the cooling chamber of the spray gun, so as to realize cooling of the spray gun during the ammonia spraying process.

[0013] 4. The utility model installs two layers of denitrification catalyst in the tail flue of the boiler, and enters the inlet of the SCR reactor after merging with the flue gas at the high-temperature flue, so that the flue gas at the SCR inlet temperature reaches 300℃-400℃, meeting the reaction temperature requirements of the SCR process. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is the principle diagram of the utility model;

[0015] In the figure: 1. Liquid extraction pump; 2. Liquid extraction pipe; 3. Ammonia storage tank; 4. Delivery pump; 5. Valve; 6. Main delivery pipe; 7. Spray gun; 8. Air compressor; 9. Cold dryer; 10. Gas storage tank; 11. Gas delivery pipe; 12. Boiler; 13. DeNOx catalyst; 14. Delivery branch pipe. DETAILED DESCRIPTION

[0016] Reference Figure 1 A hot water boiler denitrification system using a combination of SNCR+SCR, which includes: a boiler 12, a plurality of spray guns 7 installed on the boiler, a gas transmission system and an ammonia water transmission system, the main transmission pipe 6 of the ammonia water transmission system is connected to the main spray chamber of the spray gun, the spray gun is divided into a main spray gun and an external cooling chamber, the cooling chamber is used to cool the main spray gun in the form of air cooling, this structure is the structure of the prior art, and no improvement is made here, the gas transmission pipe 11 of the gas transmission system is divided into two paths, one of which is connected to the main spray chamber of the spray gun, and the other is connected to the cooling chamber of the spray gun.

[0017] The hot water boiler denitrification system adopts a combined SNCR+SCR, and the gas transmission system includes an air compressor 8 and a cold dryer 9. The air compressor is connected to the cold dryer through a pipeline, and the cold dryer is connected to the gas storage tank 10 through a pipeline. The outlet of the gas storage tank is connected to the gas transmission pipe.

[0018] The hot water boiler denitrification system adopts SNCR+SCR combination, and the ammonia water delivery system includes an ammonia water storage tank 3, the outlet of the ammonia water storage tank is connected to two delivery pipelines, and the two delivery pipelines are connected in parallel to the main delivery pipe.

[0019] The hot water boiler denitration system using the SNCR+SCR combination, the delivery pipeline includes a delivery branch pipe 14, and a delivery pump 4 and a valve 5 are installed on the delivery branch pipe.

[0020] The hot water boiler denitration system adopts the SNCR+SCR combination, and two layers of denitration catalysts 13 are installed in the tail flue of the boiler.

[0021] Working principle: Set up the extraction pump 1 and the extraction pipe 2, ammonia water can be extracted from the car, the ammonia water is 20%, and the extracted ammonia water is stored in the ammonia water storage tank. When denitration is needed, the air compressor is started, the external air is compressed by the air compressor, and then enters the cold dryer for cooling. The cooled compressed air is divided into two paths, one of which enters the main spray chamber of the spray gun, and the other enters the cooling chamber of the spray gun as cooling gas to realize the cooling of the spray gun. The ammonia water is input into the spray gun through the delivery pipeline and the main delivery pipe. The ammonia in the spray gun Water and compressed air are mixed to form mist and sprayed into the boiler through a spray gun to achieve denitrification. Two delivery pipelines are set up, one of which is used as the main pipeline and the other is used as a backup pipeline. In this way, when one of the pipelines fails, it will not affect the normal operation of the ammonia delivery system. Two layers of denitrification catalysts are installed in the tail flue of the boiler, and after merging with the flue gas at the high-temperature flue, they enter the inlet of the SCR reactor, so that the flue gas reaches 300℃-400℃ at the SCR inlet. After ammonia denitrification and the addition of two layers of denitrification catalysts, the flue gas has an average nitrogen oxide concentration of 36.67 mg / m³ per hour, and the emission indicators meet the ultra-low emission requirements.

Claims

1. A hot water boiler denitrification system using SNCR+SCR combined, comprising: A boiler, a plurality of spray guns installed on the boiler, a gas delivery system and an ammonia delivery system, wherein: the main delivery pipe of the ammonia delivery system is connected to the main spray chamber of the spray gun, and the gas delivery pipe of the gas delivery system is divided into two paths, one of which is connected to the main spray chamber of the spray gun, and the other is connected to the cooling chamber of the spray gun; The gas transmission system comprises an air compressor and a cold dryer. The air compressor is connected to the cold dryer through a pipeline. The cold dryer is connected to a gas storage tank through a pipeline. The outlet of the gas storage tank is connected to the gas transmission pipe.

2. The hot water boiler denitration system using SNCR+SCR combination according to claim 1 is characterized in that: The ammonia water delivery system comprises an ammonia water storage tank, the outlet of which is connected to two delivery pipelines, which are connected in parallel and then connected to the main delivery pipe.

3. The hot water boiler denitration system using SNCR+SCR combination according to claim 2 is characterized in that: The delivery pipeline comprises a delivery branch pipe, and a delivery pump and a valve are installed on the delivery branch pipe.

4. The hot water boiler denitration system using SNCR+SCR combination according to claim 3 is characterized in that: Two layers of denitration catalyst are installed in the tail flue of the boiler.

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