SNCR (selective non-catalytic reduction) denitration spraying system of waste incineration boiler

Abstract

The utility model discloses a waste incineration boiler SNCR (selective non-catalytic reduction) denitration spraying system which comprises a first spray gun, a second spray gun and a K-type thermocouple, and the first spray gun and the second spray gun are connected to a urea solution supply system and a compressed air supply system through pipelines; the multiple first spray guns are arranged on the upper portions of the two side walls of a second channel of the incineration boiler respectively, the multiple second spray guns are arranged on the upper portion of the rear wall of the second channel, and the multiple first spray guns and the multiple second spray guns are located on the same horizontal plane so as to form a spraying curtain wall covering the cross section of the second channel; the multiple K-type thermocouples are arranged on the upper portion of the rear wall and the upper portions of the two side walls correspondingly and used for monitoring the temperature nearby the first spray gun and the temperature nearby the second spray gun in real time. The device has the characteristics of convenience in operation, high denitration efficiency, convenience in reducing urea consumption and the like, and solves the problem that as the temperature of the first channel of the hearth often exceeds the optimal denitration reaction temperature, the denitration requirement cannot be met by purely arranging the spray gun in the first channel.

Description

Technical Field

[0001] The utility model relates to the technical field of garbage incineration treatment, in particular to a SNCR denitration spray system for a garbage incineration boiler. Background Art

[0002] The pollutants generated by a large number of waste incinerators cannot be ignored. With the continuous advancement of technology in the waste incineration industry, the flue gas emission indicators of urban domestic waste incinerators are becoming more stringent, and new requirements are put forward for the emission limits of nitrogen oxides NOx, and the NOx emission limits are getting lower and lower. At present, the denitrification technologies used in waste incineration plants are mainly concentrated on post-incineration flue gas denitrification, such as selective non-catalytic reduction technology (SNCR) and selective catalytic reduction technology (SCR).

[0003] SNCR (Selective Non-Catalytic Reduction) is a technology that uses ammonia or urea as a reducing agent to inject nitrogen oxides (NOx) into the boiler furnace at a temperature range of 850°C to 1000°C without using a catalyst. x ) is reduced to nitrogen (N2) and water (H2O).

[0004] The denitrification efficiency of SNCR technology is generally between 30% and 80%, and the specific efficiency depends on many factors, including reaction temperature, NH3 and NO x The stoichiometric ratio, mixing degree and reaction time etc.

[0005] Compared with SCR denitrification technology, SNCR sprays denitrification agent into the first channel of the incinerator at a suitable temperature window to reduce NOx, and does not require a catalyst, thus avoiding engineering problems such as catalyst blockage or poisoning. It has low investment and maintenance costs and is widely used in various industries such as electricity, cement, and waste incineration.

[0006] In the prior art, spray guns are mainly arranged in the first channel of the waste incineration boiler, and different levels of spray guns are set to meet the needs of different temperature ranges. At present, for many large-scale waste incinerators, as the calorific value of the waste gradually increases, the temperature of the first channel of the boiler also increases, and the temperature of the first channel furnace top has exceeded 1000°C. At this time, the introduction of urea into the first channel for denitrification reaction has exceeded its optimal reaction temperature range, resulting in low denitrification efficiency and high nitrogen oxide content at the flue gas emission outlet. At the same time, due to the unreasonable arrangement of urea spray guns, they cannot completely cover the entire furnace channel, resulting in large flue gas escape and poor denitrification effect. Utility Model Content

[0007] The technical problem to be solved by the utility model is to overcome the problem in the prior art that when the temperature of the first channel of the furnace exceeds the optimal reaction temperature, the denitration reaction cannot be carried out well, and therefore simply arranging a spray gun in the first channel cannot meet the denitration demand. A SNCR denitration spray system for a waste incineration boiler is provided, which has a compact structure, convenient operation, high denitration efficiency and is beneficial to reducing urea consumption.

[0008] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0009] A SNCR denitration spray system for a garbage incineration boiler comprises: a first spray gun, a second spray gun and a K-type thermocouple, wherein the first spray gun and the second spray gun are both connected to a urea solution supply system and a compressed air supply system through pipelines; a plurality of first spray guns are respectively arranged on the upper parts of two side walls of a second channel of the incineration boiler, a plurality of second spray guns are arranged on the upper part of a rear wall of the second channel of the incineration boiler, and the plurality of first spray guns and the plurality of second spray guns are all on the same horizontal plane to form a spray curtain wall covering the cross section of the second channel; a plurality of K-type thermocouples are respectively arranged on the upper part of the rear wall and the upper parts of the two side walls to monitor the temperature near the first spray gun and the second spray gun in real time.

[0010] As a further improvement of the present utility model, the first spray gun and the second spray gun are arranged on a wall in the second channel where the smoke temperature is 850°C to 1000°C.

[0011] As a further improvement of the utility model, two first spray guns are arranged on the two side walls.

[0012] As a further improvement of the present invention, the distance between the first spray gun and the end of the side wall is d1, the distance between the two first spray guns is d2, and d1:d2=1.5-2.0:1.

[0013] As a further improvement of the utility model, four second spray guns are arranged on the rear wall.

[0014] As a further improvement of the present invention, among the four second spray guns, the distance between the outermost second spray gun and the end of the rear wall is d3, the distance between the outermost second spray gun and the adjacent second spray gun is d4, and the distance between the two second spray guns located in the middle is d5, d3:d4:d5=2.0~2.2:1.1~1.2:1.

[0015] As a further improvement of the utility model, both the first spray gun and the second spray gun are dual-fluid spray guns, and the solution flow rate of a single spray gun is greater than 50 L / h.

[0016] As a further improvement of the utility model, the nozzle of the first spray gun is a conical spray nozzle, and the nozzle of the second spray gun is a flat spray nozzle.

[0017] As a further improvement of the utility model, the urea solution supply system, the compressed air supply system and the K-type thermocouple are all electrically connected to an external DCS controller. The K-type thermocouple is used to feed back the temperature information in the second channel to the DCS controller in real time. When the temperature in the second channel is higher than the preset denitrification reaction temperature, the DCS controller controls the urea solution supply system and the compressed air supply system to stop running, and the first spray gun and the second spray gun exit the second channel.

[0018] As a further improvement of the utility model, it also includes a soft water supply system and a mixer. The urea solution and soft water are mixed in the mixer according to a preset ratio and then transported to the first spray gun and the second spray gun through a pipeline.

[0019] Compared with the prior art, the advantages of the utility model are:

[0020] The utility model discloses a SNCR denitration spraying system for a garbage incineration boiler. The utility model arranges a plurality of first spray guns on the upper parts of two side walls of a second channel of the incineration boiler respectively, arranges a plurality of second spray guns on the upper part of a rear wall of the second channel of the incineration boiler, and the plurality of first spray guns and the plurality of second spray guns are all on the same horizontal plane. The first spray guns and the second spray guns are both connected to a urea solution supply system and a compressed air supply system through pipelines. The urea solution is atomized by compressed air and then sprayed through a nozzle to form a spray curtain wall covering the cross section of the second channel, thereby realizing flue gas denitration. Moreover, the flue gas temperature in the second channel is lower than that in the first channel, thereby improving the denitration efficiency, reducing the nitrogen oxide content in the flue gas, and being beneficial to protecting the environment. Meanwhile, a plurality of K-type thermocouples are respectively arranged on the upper part of the rear wall and the upper parts of the two side walls, so as to monitor the temperature near the first spray gun and the second spray gun in real time. When the temperature exceeds the optimal denitration reaction temperature, the spraying is stopped. By spraying urea in a suitable temperature field, the urea reaction rate is improved, the urea dosage is saved, and the economic benefit is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the cross-sectional structure principle of the SNCR denitrification spray system of a waste incineration boiler in a specific embodiment of the utility model.

[0022] Figure 2 It is a schematic diagram of the top structural principle of the SNCR denitrification spray system of the waste incineration boiler in the specific embodiment of the utility model.

[0023] Figure 3 It is a schematic diagram of the arrangement of the first spray gun on the side wall in a specific embodiment of the utility model.

[0024] Figure 4 It is a schematic diagram of the arrangement of the second spray gun on the rear wall in a specific embodiment of the utility model.

[0025] Legend: 1. First spray gun; 2. Second spray gun; 3. K-type thermocouple; 4. First regulating valve; 5. Second regulating valve; 6. Third regulating valve; 7. Mixer; 100. Incineration boiler; 200. Hopper; 300. First channel; 400. Second channel; 401. Side wall; 402. Rear wall; 500. Steam drum; 600. Horizontal flue; 700. Ash hopper; 800. Slag discharger. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0027] Example

[0028] like Figure 1 As shown, in the garbage incineration system, the input end of the incineration boiler 100 is connected to the hopper 200, and the garbage enters the incineration boiler 100 from the hopper 200 for incineration. The flue gas generated by the incineration of the garbage flows through the first channel 300, the second channel 400 and the horizontal flue 600 in sequence, and then is discharged. A steam drum 500 is provided at the top of the first channel 300 and the second channel 400, and a plurality of ash hoppers 700 are provided at the bottom of the horizontal flue 600. The slag generated by the incineration of the garbage is collected in the slag discharger 800 at the bottom of the incineration boiler 100.

[0029] like Figures 1 to 4 As shown, the SNCR denitration spray system of the waste incineration boiler of the utility model comprises: a first spray gun 1, a second spray gun 2 and a K-type thermocouple 3. The first spray gun 1 and the second spray gun 2 are connected to the urea solution supply system and the compressed air supply system through pipelines. A plurality of first spray guns 1 are respectively arranged on the upper part of the two side walls 401 of the second channel 400 of the incineration boiler, and a plurality of second spray guns 2 are arranged on the upper part of the rear wall 402 of the second channel 400 of the incineration boiler, and the plurality of first spray guns 1 and the plurality of second spray guns 2 are all on the same horizontal plane to form a spray curtain wall covering the cross section of the second channel 400, and a better denitration effect is achieved through fewer spray guns. A plurality of K-type thermocouples 3 are respectively arranged on the upper part of the rear wall 402 and the upper part of the two side walls 401 to monitor the temperature near the first spray gun 1 and the second spray gun 2 in real time.

[0030] In this embodiment, the first spray gun 1 and the second spray gun 2 are arranged on the wall of the second channel 400 where the flue gas temperature is 850℃~1000℃, which is just within the optimal denitration reaction temperature range. Denitration is carried out in the appropriate temperature field of the second channel, and the denitration efficiency can reach more than 45%, controlling the flue gas nitrogen oxide emission to 120mg / m 3 At the same time, the ammonia escape volume is controlled within 4mg / m 3 Inside.

[0031] In this embodiment, multiple first spray guns 1 are arranged on the upper part of the two side walls 401 of the second channel 400 of the incineration boiler, and multiple second spray guns 2 are arranged on the upper part of the rear wall 402 of the second channel 400 of the incineration boiler, and multiple first spray guns 1 and multiple second spray guns 2 are all on the same horizontal plane, and the first spray gun 1 and the second spray gun 2 are connected to the urea solution supply system and the compressed air supply system through pipelines. The urea solution is atomized by compressed air and sprayed through the nozzle to form a spray curtain wall covering the cross section of the second channel, thereby realizing flue gas denitrification. Moreover, the flue gas temperature in the second channel 400 is lower than that in the first channel 300, which improves the denitrification efficiency, reduces the nitrogen oxide content in the flue gas, and is beneficial to environmental protection. At the same time, multiple K-type thermocouples 3 are arranged on the upper part of the rear wall 402 and the upper part of the two side walls 401, respectively, to monitor the temperature near the first spray gun 1 and the second spray gun 2 in real time, to ensure that the denitrification reaction is in a better temperature field. When the temperature exceeds the optimal denitrification reaction temperature, spraying is stopped. By spraying urea in a suitable temperature field, the urea reaction rate is increased, the urea dosage is saved, and the economic benefits are improved.

[0032] In this embodiment, considering that the mixing degree of flue gas and urea spray is closely related to the denitrification efficiency, spray guns are arranged on the side wall and the rear wall of the second channel, and according to the spray width and the size of the furnace chamber, two first spray guns 1 are arranged on the two side walls 401, and four second spray guns 2 are arranged on the rear wall 402. At the same time, considering the problem of flue gas coverage, the spray guns are kept on the same plane as much as possible, and because too many spray guns will not only increase the risk of air leakage in the furnace, but also easily cause problems such as reduced boiler efficiency, the number of spray guns is reduced as much as possible under the premise of ensuring the spraying quality.

[0033] Furthermore, the distance between the first spray gun 1 and the end of the side wall 401 is d1, the distance between the two first spray guns 1 is d2, and d1:d2=1.5-2.0:1. Preferably, d1:d2=1.5:1.

[0034] Among the four second spray guns 2, the distance between the outermost second spray gun 2 and the end of the rear wall 402 is d3, the distance between the outermost second spray gun 2 and the adjacent second spray gun 2 is d4, and the distance between the two second spray guns 2 in the middle is d5, d3:d4:d5=2.0-2.2:1.1-1.2:1. Preferably, d3:d4:d5=2.1:1.1:1. By determining the intervals between the spray guns and the intervals between the spray guns and the wall, a spray cross section covering the cross section of the second channel can be formed with the least number of spray guns, avoiding spray dead angles.

[0035] In this embodiment, the first spray gun 1 and the second spray gun 2 are both dual-fluid spray guns, which can be controlled by electromagnetic valves to move forward and backward. They can be extended into the furnace when needed and withdrawn from the furnace when out of use to prevent the spray gun from burning. In order to ensure the spray effect and spray distance of the urea spray gun, the compressed air for atomization is maintained at 0.7MPa during operation, and the solution flow rate of a single spray gun is greater than 50L / h, otherwise there will not be enough water mist to bring the urea solution into the flue gas, affecting the mixing degree of the flue gas and the urea solution and affecting the denitrification efficiency. The nozzle of the first spray gun 1 adopts a conical spray nozzle, and the nozzle of the second spray gun 2 adopts a flat spray nozzle, which has the characteristics of a wider atomization coverage area.

[0036] In this embodiment, the urea solution supply system, the compressed air supply system and the K-type thermocouple 3 are all electrically connected to an external DCS controller (not shown in the figure). The K-type thermocouple 3 is used to feed back the temperature information in the second channel 400 to the DCS controller in real time. When the temperature in the second channel 400 is higher than the preset denitrification reaction temperature, the DCS controller controls the urea solution supply system and the compressed air supply system to stop running, and the first spray gun 1 and the second spray gun 2 withdraw from the second channel 400 to protect the spray guns and prevent the spray guns from burning.

[0037] like Figure 2 As shown, it also includes a soft water supply system and a mixer 7. A third regulating valve 6 is provided on the delivery pipeline of the urea solution to control the input amount of the urea solution, and a second regulating valve 5 is provided on the delivery pipeline of the soft water to control the input amount of the soft water. After the urea solution and the soft water are mixed in a preset ratio in the mixer 7, they are then transported to the first spray gun 1 and the second spray gun 2 through a pipeline. At the same time, the delivery pipeline of the urea solution and the delivery pipeline of the soft water can also be connected through a pipeline with a first regulating valve 4, so that the two solutions are pre-mixed before entering the mixer 7.

[0038] The urea solution supply system and the soft water supply system are both mature systems, which include a urea preparation tank, a urea transfer pump, a urea storage tank, a urea supply pump, a soft water storage tank, a soft water supply pump, etc. In the actual production process, the urea solution and soft water are prepared in advance for use in the denitrification system. The urea solution and the soft water solution can adjust their respective flow rates through a regulating valve, thereby controlling the concentration of the urea solution and the solution flow rate of a single spray gun. The urea solution is atomized by compressed air and sprayed into the second channel 400 of the furnace.

[0039] Although the utility model is disclosed as above with preferred embodiments, it is not intended to limit the utility model. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the utility model without departing from the spirit and technical solution of the utility model, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the utility model without departing from the content of the technical solution of the utility model still falls within the scope of protection of the technical solution of the utility model.

Claims

1. A SNCR denitrification spray system for a waste incineration boiler, characterized in that: include: A first spray gun (1), a second spray gun (2) and a K-type thermocouple (3), wherein the first spray gun (1) and the second spray gun (2) are connected to a urea solution supply system and a compressed air supply system through pipelines; a plurality of first spray guns (1) are respectively arranged on the upper part of two side walls (401) of a second channel (400) of the incineration boiler, and a plurality of second spray guns (2) are arranged on the upper part of a rear wall (402) of the second channel (400) of the incineration boiler, and the plurality of first spray guns (1) and the plurality of second spray guns (2) are all on the same horizontal plane to form a spray curtain wall covering the cross section of the second channel (400); a plurality of K-type thermocouples (3) are respectively arranged on the upper part of the rear wall (402) and the upper parts of the two side walls (401) to monitor the temperature near the first spray gun (1) and the second spray gun (2) in real time.

2. The SNCR denitrification spray system for a waste incineration boiler according to claim 1 is characterized in that: The first spray gun (1) and the second spray gun (2) are arranged on a wall in the second channel (400) where the smoke temperature is 850°C to 1000°C.

3. The SNCR denitrification spray system for a waste incineration boiler according to claim 2 is characterized in that: Two first spray guns (1) are arranged on each of the two side walls (401).

4. The SNCR denitrification spray system for a waste incineration boiler according to claim 3 is characterized in that: The distance between the first spray gun (1) and the end of the side wall (401) is d1, and the distance between the two first spray guns (1) is d2, and d1:d2=1.5-2.0:

1.

5. The SNCR denitrification spray system for a waste incineration boiler according to claim 2 is characterized in that: Four second spray guns (2) are arranged on the rear wall (402).

6. The SNCR denitrification spray system for a waste incineration boiler according to claim 5 is characterized in that: Among the four second spray guns (2), the distance between the outermost second spray gun (2) and the end of the rear wall (402) is d3, the distance between the outermost second spray gun (2) and the adjacent second spray gun (2) is d4, and the distance between the two second spray guns (2) in the middle is d5, d3:d4:d5=2.0~2.2:1.1~1.2:

1.

7. The SNCR denitrification spray system for a waste incineration boiler according to any one of claims 1 to 6, characterized in that: The first spray gun (1) and the second spray gun (2) are both dual-fluid spray guns, and the solution flow rate of a single spray gun is greater than 50 L / h.

8. The SNCR denitrification spray system for a waste incineration boiler according to claim 7 is characterized in that: The nozzle of the first spray gun (1) is a conical spray nozzle, and the nozzle of the second spray gun (2) is a flat spray nozzle.

9. The SNCR denitrification spray system for a waste incineration boiler according to any one of claims 1 to 6, characterized in that: The urea solution supply system, the compressed air supply system and the K-type thermocouple (3) are all electrically connected to an external DCS controller. The K-type thermocouple (3) is used to feed back temperature information in the second channel (400) to the DCS controller in real time. When the temperature in the second channel (400) is higher than a preset denitration reaction temperature, the DCS controller controls the urea solution supply system and the compressed air supply system to stop running, and the first spray gun (1) and the second spray gun (2) exit the second channel (400).

10. The SNCR denitrification spray system for a waste incineration boiler according to claim 9, characterized in that: It also comprises a soft water supply system and a mixer (7), wherein the urea solution and the soft water are mixed in the mixer (7) according to a preset ratio and then transported to the first spray gun (1) and the second spray gun (2) through a pipeline.

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