SCR (Selective Catalytic Reduction) ammonia injection grid device

Abstract

The utility model discloses an SCR (Selective Catalytic Reduction) ammonia spraying grating device which comprises a plurality of ammonia spraying pipes and a vertical flue, the ammonia spraying pipes are horizontally arranged and are arranged in an upper row and a lower row in the vertical flue, and ammonia in two adjacent ammonia spraying pipes on the same cross section of the vertical flue flows in different directions. Compared with the prior art, the SCR flue gas denitration system has the advantages that the system is more reliable, the spraying uniformity of the ammonia gas can be improved, the efficiency of the SCR flue gas denitration system is improved, the ammonia escape is reduced, and the SCR flue gas denitration system is more environment-friendly. And the structure is simpler than that of a common ammonia spraying grid.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of flue gas SCR denitration, especially a kind of SCR ammonia injection grid device. BACKGROUND

[0002] Denitration is the process of removing nitrogen oxides contained in waste gas generated by combustion, and the mainstream flue gas denitration technology is SCR denitration process, that is, ammonia is used as reducing agent, and ammonia and NOx in flue gas react to generate nitrogen and water under the action of catalyst.

[0003] In the SCR flue gas denitration device, the degree of uniform mixing of ammonia sprayed into flue gas and NOx in flue gas is one of the most critical factors affecting denitration efficiency, and the current injection device in SCR denitration process mainly uses ammonia injection grid (AIG), which has various forms and structures.

[0004] The ammonia injection grid includes ammonia injection inlet pipeline, ammonia gas regulating valve, ammonia gas flowmeter, ammonia gas branch pipe, ammonia injection grid device and nozzle, etc., and the diluted ammonia gas is transported to the ammonia injection grid device through the ammonia injection inlet pipeline after passing through the ammonia gas regulating valve and the ammonia gas flowmeter, and is sprayed into the flue from the nozzle of the ammonia injection grid, mixed with flue gas, and finally reacts with NOx on the surface of the catalyst. When the ammonia injection grid is not properly designed or the flue gas flow distribution is not reasonable, the mixing of NOx and NH3 is not uniform, which not only affects the denitration efficiency, but also causes local ammonia injection excess, which not only wastes a lot of ammonia, but also a large amount of ammonia escape will seriously damage the environment.

[0005] With the large-scale implementation of domestic ultra-low emission policy, SCR inlet zoning ammonia injection and outlet zoning NOx / NH3 patrol measurement have become standard, and reasonable ammonia injection grid structure can ensure uniform mixing of reducing agent and NOx in the denitration zoning as much as possible, which not only reduces investment cost, but also makes the mutual influence of ammonia injection amount and mixing effect between each zone smaller during debugging and running, and the system maintenance and operation will be simpler and more reliable, which has become a technical problem to be solved in the field.

[0006] Domestic denitration manufacturers have done a lot of research on different working conditions and applied for a large number of patents, and the ammonia injection grid forms are various, and the advantages and disadvantages are different; such as the authorized announcement number CN219964513U "flue gas denitration ammonia injection grid", when ammonia injection is in a deep flue, uneven phenomenon is easy to occur; such as the authorized announcement number CN221385923U "SCR denitration ammonia injection grid device", the ammonia injection amount of each nozzle cannot be controlled uniformly; such as the authorized announcement number CN219879563U "multistage equal resistance ammonia injection grid", although the ammonia injection branch pipe is designed to be equal resistance, the ammonia injection amount is relatively uniform, but the system is very complex, and the ammonia injection pipeline resistance is very large; such as the authorized announcement number CN205796965U "flue gas SCR denitration ammonia injection grid structure of coal-fired power plant", the diameter of the ammonia gas main pipe is reduced along the flow direction, but the local variable diameter design cannot guarantee uniform ammonia injection; such as the authorized announcement number CN206621995U "a new type of ammonia injection grid" and the application publication number CN115105938A "flue gas denitration efficient regulation and control ammonia injection grid and ammonia injection amount calculation method", the ammonia injection amount of the nozzles on the same branch pipe cannot be guaranteed to be uniform, if the uniformity of the ammonia injection amount is to be improved, the system will be more complex, a large number of regulating valves and flow meters need to be added, which not only makes the debugging and operation and maintenance more troublesome, but also greatly increases the investment cost. SUMMARY

[0007] The purpose of the utility model is to solve the problems in the prior art, propose a SCR ammonia injection grid device, which can improve the uniformity of ammonia injection, thereby improving the efficiency of the SCR flue gas denitration system, and has a simple structure.

[0008] In order to achieve the above-mentioned purpose, the utility model provides a SCR ammonia injection grid device, which comprises a plurality of ammonia injection pipes and a vertical flue, the ammonia injection pipes are arranged in two rows vertically and horizontally in the vertical flue, the ammonia in the adjacent two ammonia injection pipes on the same cross section of the vertical flue flows in different directions, the input end of each ammonia injection pipe is sequentially connected with an ammonia flow meter and an ammonia regulating valve located outside the flue, and a plurality of nozzles are arranged on each ammonia injection pipe.

[0009] As a preferred, the two rows of ammonia injection pipes are arranged alternately.

[0010] As a preferred, the row spacing Z of the two rows of ammonia injection pipes is 400mm-600mm, and the spacing X of the adjacent two ammonia injection pipes on the same cross section of the flue is 700mm-900mm.

[0011] As a preferred, the nozzles are arranged obliquely on the back smoke side of the ammonia injection pipe, the diameter of the nozzle is 10mm-30mm, the oblique directions of the adjacent two nozzles are opposite, the included angle a formed by the adjacent two nozzles is 60°-120°, and the spacing Y between the adjacent two nozzles is 100-300mm.

[0012] Preferably, the ammonia injection lances are provided with baffles on the upstream side, and the baffles are provided with blocking pieces corresponding to the nozzles.

[0013] The utility model discloses a beneficial effect: the utility model discloses a horizontal arrangement and in the vertical flue form upper and lower two rows of ammonia injection lances, the ammonia gas of two ammonia injection lances on the same cross section of flue opposite flow, the input of ammonia injection lance all sequentially has the ammonia flowmeter and ammonia regulating valve of being located outside flue, the ammonia injection lance all is equipped with a plurality of nozzles, compared with prior art, the system is more reliable, and the uniformity of ammonia injection can be improved, thereby improving the efficiency of the SCR flue gas denitration system, reducing ammonia escape, and the structure is simpler than general ammonia injection grid.

[0014] The features and advantages of the utility model will be described in detail with embodiments combined with the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a facade schematic view of the utility model discloses a kind of SCR ammonia injection grid device;

[0016] Figure 2 It is Figure 1 Front view of nozzle being arranged on ammonia injection lance in it;

[0017] Figure 3 It is the ammonia injection lance arrangement drawing of upper row;

[0018] Figure 4 It is the ammonia injection lance arrangement drawing of lower row.

[0019] In the drawing: 1-ammonia injection lance, 2-vertical flue, 3-ammonia flowmeter, 4-ammonia regulating valve, 5-nozzle, 6-baffle, 7-blocking piece. DETAILED DESCRIPTION

[0020] Refer to Figure 1 , Figure 2 , Figure 3 And Figure 4 , the utility model discloses a kind of SCR ammonia injection grid device, including a plurality of ammonia injection lances 1 and vertical flue 2, the ammonia injection lance 1 is horizontally arranged and in vertical flue 2 form upper and lower two rows, the ammonia gas of two ammonia injection lances 1 on the same cross section of flue 2 opposite flow, the input of ammonia injection lance 1 all sequentially has the ammonia flowmeter 3 and ammonia regulating valve 4 located outside flue 2, the ammonia injection lance 1 all is equipped with a plurality of nozzles 5.

[0021] The upper and lower rows of ammonia injection pipes 1 are staggered, and the row spacing Z of the upper and lower rows of ammonia injection pipes 1 is 400-600 mm, and the spacing X between the adjacent two ammonia injection pipes 1 on the same cross section of the flue 2 is 700-900 mm.

[0022] The nozzle 5 is obliquely arranged on the back smoke side of the ammonia injection pipe 1, the diameter of the nozzle 5 is 10-30 mm, the oblique directions of the adjacent two nozzles 5 are opposite, the included angle a formed by the adjacent two nozzles 5 is 60-120°, and the spacing Y between the adjacent two nozzles 5 is 100-300 mm.

[0023] The front smoke side of the ammonia injection pipe 1 is provided with a baffle 6, and the baffle 6 is provided with a blocking piece 7 corresponding to the nozzle 5.

[0024] The working process of the utility model:

[0025] In the working process of the utility model, ammonia enters the ammonia injection pipe 1, and then is uniformly injected into the flue through the nozzle 5.

[0026] Each single ammonia injection pipe 1 is provided with an ammonia flow meter 3 and an ammonia adjusting valve 4, so that the flow of any ammonia injection pipe 1 is basically consistent, the uniformity of ammonia injection is improved, the efficiency of the SCR flue gas denitration system is improved, the structure is simple, the ammonia escape can be ensured to be not over standard, and the investment cost is obviously reduced.

[0027] The row spacing Z of the upper and lower rows of ammonia injection pipes 1 is 400-600 mm, the spacing X between the adjacent two ammonia injection pipes 1 on the same cross section of the flue 2 is 700-900 mm, the nozzle 5 is obliquely arranged on the back smoke side of the ammonia injection pipe 1, the diameter of the nozzle 5 is 10-30 mm, the oblique directions of the adjacent two nozzles 5 are opposite, the included angle a formed by the adjacent two nozzles 5 is 60-120°, and the spacing Y between the adjacent two nozzles 5 is 100-300 mm, so that the uniformity of ammonia injection is further improved, and the denitration efficiency is improved.

[0028] The above embodiments are used to illustrate the utility model, and are not used to limit the utility model, and any simple transformation of the utility model belongs to the protection range of the utility model.

Claims

1. An ammonia injection grid device for an SCR, characterized by: The application relates to a vertical flue (2) and a plurality of ammonia injection lances (1), the ammonia injection lances (1) are horizontally arranged and arranged in two rows in the vertical flue (2), ammonia in two adjacent ammonia injection lances (1) in the same cross section of the vertical flue (2) flows in different directions, the input end of each ammonia injection lance (1) is sequentially connected with an ammonia flow meter (3) and an ammonia regulating valve (4) outside the vertical flue (2), and a plurality of nozzles (5) are arranged on each ammonia injection lance (1).

2. An SCR ammonia injection grid apparatus as set forth in claim 1 characterized by: The two rows of ammonia injection lances (1) are staggered.

3. An SCR ammonia injection grid apparatus as recited in claim 2 wherein: The row spacing Z of the two adjacent rows of ammonia injection lances (1) is 400mm-600mm, and the spacing X of the two adjacent ammonia injection lances (1) in the same cross section of the vertical flue (2) is 700mm-900mm.

4. An SCR ammonia injection grid apparatus as recited in claim 1 wherein: The nozzles (5) are arranged on the back smoke side of the ammonia injection lances (1), the diameter of the nozzles (5) is 10mm-30mm, the inclination directions of the two adjacent nozzles (5) are opposite, the included angle a formed by the two adjacent nozzles (5) is 60-120, and the spacing Y of the two adjacent nozzles (5) is 100-300mm.

5. An SCR ammonia injection grid apparatus according to any one of claims 1 to 4, characterized in that: The front smoke side of the ammonia injection lances (1) is provided with baffles (6), and the baffles (6) are provided with blocking pieces (7) corresponding to the nozzles (5) one by one.

Images