CN115672019A

CN115672019A - Layered and zoned adjustment type ammonia injection denitration device and denitration method thereof

Info

Publication number: CN115672019A
Application number: CN202211435479.2A
Authority: CN
Inventors: 沈松仁; 许海锋; 朱金水
Original assignee: Hangzhou Hangmin Thermal Power Co ltd
Current assignee: Hangzhou Hangmin Thermal Power Co ltd
Priority date: 2022-11-16
Filing date: 2022-11-16
Publication date: 2023-02-03

Abstract

The utility model relates to an ammonia denitrification facility is spouted to layering subregion regulation type, it includes flue mechanism, detection sampling mechanism and spouts ammonia mechanism, and flue mechanism includes reaction tower, a plurality of grid board and drive assembly, be equipped with into mouth and outlet flue on the reaction tower, the grid board rotate connect in the reaction tower, a plurality of grid board interval distribution and mutual parallel arrangement, drive assembly can order about a plurality ofly the grid board rotates, and the rotation opposite direction of adjacent grid board, be equipped with a plurality of through-holes on the grid board, the pore length of through-hole is greater than the thickness of grid board, it locates in the reaction tower and is located and be close to detect sampling mechanism the one end of outlet flue, it is used for taking a sample to the flue gas in the reaction tower to detect sampling mechanism, it is used for spouting the ammonia processing to the reaction tower between the interval of a plurality of grid boards to spout ammonia mechanism locates. This application has the accuracy that improves the flue gas detection, improves denitration efficiency's effect.

Description

Layered and zoned adjustment type ammonia injection denitration device and denitration method thereof

Technical Field

The application relates to the technical field of ammonia injection denitration, in particular to a layered and partitioned adjustment type ammonia injection denitration device and a denitration method thereof.

Background

In the ecological environment control of China, the emission of nitrogen oxides in a power plant is a main factor causing environmental problems such as acid rain and the like. China also puts forward the emission standard of nitrogen oxides one after another. The nitrogen oxide emission reduction technology commonly used in coal-fired power plants comprises a low-nitrogen combustion technology, a non-selective catalytic reduction technology and a selective catalytic reduction technology. The combination or combination of different denitration technologies is an important development direction of the denitration technology, and the development direction is developed for innovating a denitration mechanism and researching and developing a multi-stage composite denitration technology.

The selective catalytic reduction technology is a commonly used denitration technology at present, and means that a reducing agent selectively reacts with nitrogen oxides in flue gas to generate harmless nitrogen and water in a certain temperature range in the presence of a catalyst and oxygen so as to remove the nitrogen oxides in the flue gas.

In view of the above-mentioned related technologies, the inventor believes that, because flue gas in the flue presents a turbulent flow field and is close to the reducing flue, the flow of flue gas on the wall surface is more disordered, the cross section area of the flue is large, the distribution of flue gas components is uneven, and the flow rate is inconsistent, so that representative flue gas cannot be obtained, further, the detection sampling is not enough to reflect the flue gas components of the whole flue, and the detection accuracy of denitration flue gas is poor.

Disclosure of Invention

In order to improve the accuracy of flue gas detection and improve denitration efficiency, the application provides a layered and zoned regulation type ammonia injection denitration device and a denitration method thereof.

First aspect, this application provides a hierarchical subregion regulation type spouts ammonia denitrification facility, adopts following technical scheme:

the utility model provides a layering subregion regulation type spouts ammonia denitrification facility, includes flue mechanism, detection sampling mechanism and spouts ammonia mechanism, flue mechanism includes reaction tower, a plurality of grid board and drive assembly, be equipped with into mouth and outlet flue on the reaction tower, the grid board rotate connect in the reaction tower, a plurality of grid board interval distribution and mutual parallel arrangement, drive assembly can order about a plurality ofly the grid board rotates, and adjacent the rotation opposite direction of grid board, be equipped with a plurality of through-holes on the grid board, the pore length of through-hole is greater than the grid board thickness, it locates to detect sampling mechanism just be located in the reaction tower and be located and be close to the one end of outlet flue, it is used for taking a sample to the flue gas in the reaction tower to detect sampling mechanism, it locates a plurality ofly to spout ammonia mechanism is used for spouting ammonia processing in the reaction tower between the interval of grid board.

Through adopting the above-mentioned technical scheme, when needing to spout ammonia denitration treatment to the flue gas, the flue gas gets into in the reaction tower through advancing the mouth, the through-hole that the flue gas passes through the grid board upwards flows, at the in-process that the flue gas flows, order about the grid board through drive assembly and rotate, make the position of flue gas when getting into the through-hole and the position when flowing out the through-hole change, and then effectively improve the homogeneity of flue gas in the reaction tower, through setting up a plurality of grid boards, and order about the opposite direction of rotation of adjacent grid board, at grid board pivoted in-process, make the flue gas position of different positions constantly take place to change the flue gas of other positions in the reaction tower and mix, improve the homogeneity of flue gas in the reaction tower, and then effectively improve flue gas detection's accuracy, and when the flue gas homogeneity of reaction tower is good, the convenience is controlled the ammonia injection volume, effectively improve deamination efficiency.

Optionally, the driving assembly includes a driving box, a driving member, a driving shaft, a bevel gear set and an annular rack, the driving box is disposed on one side of the reaction tower, the driving shaft is rotatably connected to the inside of the driving box, the annular rack is fixedly disposed on the periphery of the grating plate, the bevel gear set is disposed between the driving shaft and the annular rack and used for transmitting the driving shaft and the annular rack, and the driving member is used for driving the driving shaft to rotate.

Through adopting above-mentioned technical scheme, when carrying out denitration treatment to the flue gas, when needing to rotate the homogeneity that improves flue gas in the reaction tower through the grid board, order about the drive shaft through the driving piece and rotate, at drive shaft pivoted in-process, carry out the transmission through bevel gear group and then drive the rotation of annular rack to order about the rotation opposite direction of adjacent grid board, and then realize the drive effect to the grid board, improve the homogeneity of flue gas in the reaction tower.

Optionally, it is a plurality of be equipped with one between per two in proper order the bevel gear group, bevel gear group includes drive tooth, first bevel gear and two second bevel gears, the drive tooth coaxial set firmly in the drive shaft, second bevel gear rotate connect in the drive incasement and with the grid board correspond the setting, first bevel gear with the annular rack meshing, first bevel gear rotate connect in the drive incasement with the drive tooth meshing, two second bevel gear is located first bevel gear's upper and lower both sides, and all with first bevel gear meshing.

Through adopting above-mentioned technical scheme, when ordering about the grid board and rotating, when the driving piece ordered about the drive shaft and rotated, the drive shaft drove first bevel gear and rotated, because two second bevel gears are located first bevel gear's upper and lower both sides, and then when first bevel gear pivoted, order about two second bevel gears and rotate, and rotation direction is opposite, and second bevel gear drives the grid board through annular rack again and rotates, and then realizes that a drive drives a plurality of grid boards simultaneously and rotates, and makes the rotation direction of adjacent grid board opposite.

Optionally, the upper and lower both sides that the grid board with the reaction tower is connected all are equipped with the sealing ring, the grid board bottom is inlayed and is equipped with a plurality of balls, the ball with be located the sealing ring roll connection of downside.

By adopting the technical scheme, the sealing performance of the reaction tower is improved through the arranged sealing ring, and the leakage of smoke from the joint of the grid plate and the driving assembly is avoided; and through inlay at grid plate bottom and establish the ball, replace sliding friction through the rolling friction of ball, reduce the grid plate and continuously rotate the wearing and tearing that cause the device, and then improve life.

Optionally, the pore passage of the through hole is in a spiral structure in the grid plate.

Through adopting above-mentioned technical scheme, become the heliciform through the pore that sets up the through-hole and improve the length of pore in the grid board, increase the flow path of flue gas in the grid board, and then improve the dwell time of flue gas in the grid board, the flue gas misce bene in order about the reaction tower that can be better in grid board pivoted in-process, and then improve sample detection's accuracy.

It is optional, spout ammonia mechanism includes that jet-propelled is responsible for, a plurality of branch pipes and shower nozzle, jet-propelled is responsible for and stretches into adjacently between the grid plate, and is a plurality of the branch pipe is located jet-propelled is responsible for, and is a plurality of the branch pipe is radial structure, and is a plurality of shower nozzle evenly distributed is in the branch pipe lateral wall, and the shower nozzle orientation the grid plate.

By adopting the technical scheme, when the flue gas in the reaction tower is treated and the flue gas flows between the grating plates in the reaction tower, ammonia gas is sprayed into the flue gas in the reaction tower through the spray head to carry out denitration treatment on the flue gas; because the ammonia injection mechanism is arranged between the adjacent grating plates, in the denitration treatment, the denitration efficiency is greatly improved through the graded multiple ammonia injection denitration treatment.

Optionally, the detection sampling mechanism comprises a plurality of exhaust pipes uniformly distributed in the reaction tower, the exhaust pipes extend into the opening of one end of the reaction tower and face away from the grid plate, and the other ends of the exhaust pipes are communicated with the detection system.

By adopting the technical scheme, the reaction tower arranged by the detection sampling mechanism is close to one end of the smoke outlet, and after the smoke is mixed in the rotating process of the plurality of grating plates, the smoke in the reaction tower is gradually close to the smoke outlet, so that the smoke is mixed more uniformly, the uniformity of the smoke concentration sampled by the exhaust pipe is better, the sampling accuracy is greatly improved, and the accurate control of ammonia spraying amount is achieved; and the pipe orifice through setting up the exhaust tube deviates from the grating board, because the flue gas is walked upwards, can avoid the flue gas constantly to fill and cause the jam in the exhaust tube into the exhaust tube.

In a second aspect, the application provides an ammonia injection denitration method, which adopts the following technical scheme:

an ammonia injection denitration method comprises the following steps:

s1: smoke is introduced through the smoke inlet, the plurality of grid plates are driven to rotate through the driving assembly, and ammonia gas is sprayed into the reaction tower through the ammonia spraying mechanism;

s2: after smoke sequentially passes through the through holes of the grating plates, sampling is carried out through a detection sampling mechanism, and the concentration of nitrogen oxide is detected through a detection system;

s3: adjusting the ammonia spraying amount of the ammonia spraying mechanism according to the concentration detected by the detection system in the step S2, and increasing the ammonia spraying amount when the concentration is higher; otherwise, the ammonia injection amount is reduced.

In summary, the present application includes at least one of the following beneficial technical effects:

1. by arranging the plurality of grid plates, the plurality of grid plates are driven to rotate, and the rotating directions of the adjacent grid plates are opposite, so that the flue gas at different positions in the reaction tower continuously changes, and the flue gas at other positions is mixed, the uniformity of the flue gas in the reaction tower is improved, the accuracy of flue gas detection is further effectively improved, and when the uniformity of the flue gas in the reaction tower is good, the deamination efficiency can be effectively improved;

2. the driving assembly comprises the driving box, the driving part, the driving shaft, the bevel gear group and the annular rack, the plurality of grid plates are driven by one power source of the driving part, the rotating directions of the adjacent grid plates are opposite, the uniformity of smoke in the reaction tower is improved, and the effects of high efficiency and energy saving are achieved;

3. the ammonia spraying denitration method comprises the steps of firstly spraying ammonia after flue gas in the uniform reaction tower passes through, then sampling through the detection sampling mechanism, detecting the concentration of nitrogen oxide through the detection system, adjusting the ammonia spraying amount according to the detected concentration, conveniently controlling the ammonia spraying amount, and effectively improving the deamination efficiency.

Drawings

Fig. 1 is a schematic structural diagram of a layered and zoned adjustment type ammonia injection denitration device according to an embodiment of the present application.

Fig. 2 is a perspective sectional view of a layered and zoned adjustment type ammonia injection denitration device according to an embodiment of the present application.

Fig. 3 is an enlarged schematic view of a portion a of fig. 2.

Reference numerals: 1. a flue mechanism; 11. a reaction tower; 111. a smoke inlet; 112. a smoke outlet; 113. a seal ring; 114. a ball bearing; 12. a grid plate; 121. a through hole; 13. a drive assembly; 131. a drive box; 132. a drive member; 133. a drive shaft; 134. an annular rack; 135. a driving tooth; 136. a first bevel gear; 137. a second bevel gear; 2. a detection sampling mechanism; 21. an air exhaust pipe; 3. an ammonia spraying mechanism; 31. a main air injection pipe; 32. a branch pipe; 33. and (4) a spray head.

Detailed Description

The present application is described in further detail below with reference to figures 1-3.

The embodiment of the application discloses ammonia denitrification facility is spouted to layering subregion regulation type. Referring to fig. 1, 2 and 3, the layered and zoned adjustment type ammonia injection denitration device includes a flue mechanism 1, a detection sampling mechanism 2 and an ammonia injection mechanism 3; the flue mechanism 1 comprises a reaction tower 11, a plurality of grating plates 12 and a driving component 13, wherein a smoke inlet 111 and a smoke outlet 112 are formed in the reaction tower 11, the grating plates 12 are rotatably connected in the reaction tower 11, the axial direction of the grating plates 12 is the same as the axial direction of the main body of the reaction tower 11, the plurality of grating plates 12 are distributed at intervals and are arranged in parallel, the number of the grating plates 12 can be two, four or six, all that is, the rotation of the plurality of grating plates 12 can be used for uniformly mixing the smoke in the reaction tower 11, and the number of the grating plates 12 is four in the embodiment; a plurality of through holes 121 are formed in the grating plate 12, and the length of the pore passage of each through hole 121 is greater than the thickness of the grating plate 12; the grid plate 12 is driven to rotate, so that the position of the flue gas entering the through hole 121 and the position of the flue gas flowing out of the through hole 121 are changed, and the uniformity of the flue gas in the reaction tower 11 is effectively improved. The pore channels of the through holes 121 form a spiral structure in the grid plate 12, so that the flow path of the flue gas in the grid plate 12 is increased, the retention time of the flue gas in the grid plate 12 is prolonged, and the flue gas in the reaction tower 11 can be better driven to be more uniformly mixed in the rotating process of the grid plate 12; the upper side and the lower side of the grid plate 12 connected with the reaction tower 11 are both provided with sealing rings 113, and the sealing rings 113 are fixedly connected with the inner wall of the reaction tower 11, so that the sealing performance of the reaction tower 11 is improved, and the leakage of flue gas is avoided; a plurality of balls 114 are embedded in the bottom of the grating plate 12, and the balls 114 are in rolling connection with a sealing ring 113 positioned on the lower side, so that the abrasion of the device caused by the continuous rotation of the grating plate 12 is reduced, and the service life is further prolonged.

Referring to fig. 2 and 3, the driving assembly 13 can drive the plurality of grid plates 12 to rotate, and the rotation directions of adjacent grid plates 12 are opposite, the driving assembly 13 includes a driving box 131, a driving member 132, a driving shaft 133, a bevel gear set and an annular rack 134, the driving box 131 is integrally connected to the outer side wall of the reaction tower 11, the driving shaft 133 is rotatably connected to the driving box 131 along the axial direction of the reaction tower 11, the annular rack 134 is integrally connected to the peripheral side of the grid plates 12, the bevel gear set is installed in the driving box 131 and located between the driving shaft 133 and the annular rack 134, the bevel gear set is used for transmitting between the driving shaft 133 and the annular rack 134, the driving member 132 is used for driving the driving shaft 133 to rotate, in this embodiment, the driving member 132 is a motor, the driving member 132 is installed on the outer wall of the driving box 131, an output shaft of the driving member 132 extends into the driving box 131 and is coaxially and fixedly connected to the driving shaft 133, the driving member 132 drives the driving shaft 133 to rotate, and, during the rotation of the driving shaft 133, the bevel gear set is used for driving the annular rack 134 to rotate, thereby driving the rotation of the plurality of grid plates 12.

Referring to fig. 2 and 3, a bevel gear set is arranged between every two of the four grid plates 12 in sequence, the bevel gear set includes a driving tooth 135, a first bevel gear 136 and two second bevel gears 137, the driving tooth 135 is coaxially and fixedly arranged on the driving shaft 133, the second bevel gears 137 are rotatably connected in the driving box 131 through a rotating shaft and are arranged corresponding to the grid plates 12, the first bevel gears 136 are engaged with the annular rack 134, the first bevel gears 136 are rotatably connected in the driving box 131 through a rotating shaft and are engaged with the driving tooth 135, the two second bevel gears 137 are arranged at the upper and lower sides of the first bevel gears 136, and one side of the first bevel gears 136 close to the reaction tower 11 is provided with bevel gear surfaces engaged with the second bevel gears 137 and are both engaged with the first bevel gears 136; the driving shaft 133 drives the first bevel gear 136 to rotate, and since the two second bevel gears 137 are located at the upper and lower sides of the first bevel gear 136, the two second bevel gears 137 are driven to rotate while the first bevel gear 136 rotates, and the rotation directions are opposite, so that the rotation directions of the adjacent grating plates 12 are opposite.

Referring to fig. 1 and 2, the detection sampling mechanism 2 is installed in the reaction tower 11 and located at one end close to the smoke outlet 112, the detection sampling mechanism 2 is used for sampling smoke in the reaction tower 11, the detection sampling mechanism 2 includes a plurality of air exhaust pipes 21 uniformly distributed in the reaction tower 11, the air exhaust pipes 21 are radial in the horizontal direction of the reaction tower 11, at least two air exhaust pipes 21 are arranged in the same direction, the lengths of the air exhaust pipes 21 are different, and by setting the distribution mode of the air exhaust pipes 21, sampling can be performed at a plurality of positions in the reaction tower 11, so that the sampling accuracy is improved; the pipe orifices of the plurality of air exhaust pipes 21 extending into one end of the reaction tower 11 face away from the grating plate 12, so that the blockage of the air exhaust pipes 21 caused by the continuous filling of flue gas into the air exhaust pipes 21 can be avoided; the other end of exhaust tube 21 is used for and detecting system intercommunication, sends into detecting system in the detection system detection and analysis after taking a sample through exhaust tube 21, can make clear the composition concentration of the interior processing back flue gas of reaction tower 11, and the convenience is adjusted the ammonia injection volume.

Referring to fig. 1 and 2, the ammonia spraying mechanism 3 is disposed between the plurality of grid plates 12 for spraying ammonia into the reaction tower 11, the ammonia spraying mechanism 3 includes a main gas spraying pipe 31, a plurality of branch pipes 32 and a nozzle 33, the main gas spraying pipe 31 extends into the space between the adjacent grid plates 12, the plurality of branch pipes 32 are communicated with the main gas spraying pipe 31, the plurality of branch pipes 32 are in a radial structure along the horizontal direction, the plurality of nozzles 33 are uniformly distributed on the side walls of the branch pipes 32, the nozzle 33 is specifically an atomizing nozzle 33, the nozzle 33 faces the grid plates 12, and the branch pipes 32 and the nozzle 33 are disposed between the adjacent grid plates 12; spraying ammonia gas into the flue gas in the reaction tower 11 through a spray head 33 to carry out denitration treatment on the flue gas; because the ammonia injection mechanism 3 is arranged between the adjacent grating plates 12, in the denitration treatment, the denitration efficiency is greatly improved through the graded multiple ammonia injection denitration treatment.

The implementation principle of the layered and partitioned regulation type ammonia spraying denitration device in the embodiment of the application is as follows: when ammonia spraying denitration treatment needs to be carried out on flue gas, the flue gas enters the reaction tower 11 through the smoke inlet 111, the driving part 132 and the ammonia spraying mechanism 3 are started simultaneously, the driving component 13 drives the grid plates 12 to rotate, the flue gas flows upwards through the through holes 121 of the grid plates 12, due to the rotation of the grid plates 12, the positions of the flue gas entering the through holes 121 and the positions of the flue gas flowing out of the through holes 121 are changed, the flue gas in the reaction tower 11 is uniform after being treated by the multiple layers of grid plates 12, meanwhile, the spray nozzles 33 spray ammonia gas into the flue gas in the reaction tower 11, when the flue gas flows to the detection sampling mechanism 2, air suction sampling analysis is carried out through the air suction pipe 21, the ammonia spraying amount is adjusted through detection on the flue gas concentration of the smoke outlet 112, and accurate control on the ammonia spraying amount is achieved.

The embodiment of the application also discloses an ammonia injection denitration method, and with reference to fig. 2, the layered and zoned adjustment type ammonia injection denitration device comprises the following steps:

s1: smoke is introduced through the smoke inlet 111, the plurality of grid plates 12 are driven to rotate through the driving assembly 13, and ammonia gas is sprayed into the reaction tower 11 through the ammonia spraying mechanism 3;

s2: after the flue gas passes through the through holes 121 of the grating plates 12 in sequence, sampling is carried out through the detection sampling mechanism 2, and the concentration of nitrogen oxides is detected through the detection system;

s3: according to the concentration detected by the detection system in the step S2, the ammonia spraying amount of the ammonia spraying mechanism 3 is adjusted, and when the concentration is higher, the ammonia spraying amount is increased; otherwise, the ammonia injection amount is reduced.

The above are preferred embodiments of the present application, and the scope of protection of the present application is not limited thereto, so: equivalent changes in structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The utility model provides a layering subregion regulation type spouts ammonia denitrification facility which characterized in that: including flue mechanism (1), detection sampling mechanism (2) and spout ammonia mechanism (3), flue mechanism (1) is including reaction tower (11), a plurality of grid board (12) and drive assembly (13), be equipped with on reaction tower (11) and advance mouth (111) and outlet flue (112), grid board (12) rotate connect in reaction tower (11), a plurality of grid board (12) interval distribution and mutual parallel arrangement, drive assembly (13) can order about a plurality of grid board (12) rotate, and adjacent the direction of rotation of grid board (12) is opposite, be equipped with a plurality of through-holes (121) on grid board (12), the pore length of through-hole (121) is greater than the thickness of grid board (12), it locates to detect sampling mechanism (2) just be located in reaction tower (11) and be close to the one end of outlet flue (112), it is used for taking a sample to the flue gas in reaction tower (11) to detect sampling mechanism (2), it locates to spout ammonia mechanism (3) a plurality of grid board (12) between be used for ammonia interval processing in reaction tower (11).

2. The layered and zoned regulation type ammonia injection denitration device according to claim 1, characterized in that: the driving assembly (13) comprises a driving box (131), a driving piece (132), a driving shaft (133), a bevel gear set and an annular rack (134), the driving box (131) is arranged on one side of the reaction tower (11), the driving shaft (133) is rotationally connected into the driving box (131), the annular rack (134) is fixedly arranged on the peripheral side of the grating plate (12), the bevel gear set is arranged between the driving shaft (133) and the annular rack (134) and is used for transmitting the driving shaft (133) and the annular rack (134), and the driving piece (132) is used for driving the driving shaft (133) to rotate.

3. The layered and zoned adjustment type ammonia injection denitration device according to claim 2, characterized in that: the grid plates (12) are sequentially provided with one bevel gear set between every two of the grid plates (12), each bevel gear set comprises a driving tooth (135), a first bevel gear (136) and two second bevel gears (137), the driving tooth (135) is coaxially and fixedly arranged on the driving shaft (133), the second bevel gears (137) are rotatably connected into the driving box (131) and are correspondingly arranged with the grid plates (12), the second bevel gears (137) are meshed with the annular racks (134), the first bevel gears (136) are rotatably connected into the driving box (131) and are meshed with the driving teeth (135), and the two second bevel gears (137) are located on the upper side and the lower side of the first bevel gears (136) and are meshed with the first bevel gears (136).

4. The layered and zoned adjustment type ammonia injection denitration device according to claim 1, characterized in that: the upper and lower both sides that grid plate (12) with reaction tower (11) are connected all are equipped with sealing ring (113), grid plate (12) bottom is inlayed and is equipped with a plurality of balls (114), ball (114) and sealing ring (113) roll connection who is located the downside.

5. The layered and zoned adjustment type ammonia injection denitration device according to claim 1, characterized in that: the pore canal of the through hole (121) forms a spiral structure in the grating plate (12).

6. The layered and zoned regulation type ammonia injection denitration device according to claim 1, characterized in that: spout ammonia mechanism (3) and include that jet-propelled is responsible for (31), a plurality of branch pipe (32) and shower nozzle (33), jet-propelled is responsible for (31) and stretches into adjacently between grid board (12), and is a plurality of branch pipe (32) are located jet-propelled is responsible for on (31), and a plurality of branch pipe (32) are radial structure, and are a plurality of shower nozzle (33) evenly distributed is in branch pipe (32) lateral wall, and shower nozzle (33) orientation grid board (12).

7. The layered and zoned adjustment type ammonia injection denitration device according to claim 1, characterized in that: the detection sampling mechanism (2) comprises a plurality of air exhaust pipes (21) which are uniformly distributed in the reaction tower (11), the air exhaust pipes (21) stretch into the opening of one end of the reaction tower (11) and face away from the grating plate (12), and the other end of each air exhaust pipe (21) is communicated with a detection system.

8. An ammonia injection denitration method is characterized in that: the layered and zoned adjustment type ammonia injection denitration device according to any one of claims 1 to 7, comprising the following steps:

s1: smoke is introduced through the smoke inlet (111), the plurality of grid plates (12) are driven to rotate by the driving assembly (13), and ammonia gas is sprayed into the reaction tower (11) through the ammonia spraying mechanism (3);

s2: after smoke sequentially passes through the through holes (121) of the grating plates (12), sampling is carried out through the detection sampling mechanism (2), and the concentration of nitrogen oxide is detected through the detection system;

s3: according to the concentration detected by the detection system in the S2, the ammonia spraying amount of the ammonia spraying mechanism (3) is adjusted, and when the concentration is higher, the ammonia spraying amount is increased; otherwise, the ammonia injection amount is reduced.