Anhydrous ammonia process denitration process

Abstract

The invention provides an anhydrous ammonia process denitration device and process, and relates to the technical field of tunnel kiln denitration, the anhydrous ammonia process denitration device comprises a fan chamber and a powder making bin, a circular hopper is installed at the top of the powder making bin, a rotatable disc type feeder is arranged at the bottom of the circular hopper, a double-roller type mill is arranged below the disc type feeder, and the double-roller type mill is arranged below the circular hopper. According to the invention, an anhydrous ammonia process (SNCR) technology is adopted, urea particles are jetted and subjected to a reduction reaction with nitrogen oxides (NOx) in flue gas to generate nitrogen and water, so that the concentration of NOx in the flue gas can be effectively reduced, strict standards (for example, NOx emission is less than or equal to 50mg / Nm) of countries and regions on NOx emission of industrial kilns are met, the emission of NOx is less than or equal to 50mg / Nm, the emission of NOx is less than or equal to 50mg / Nm, the emission of NOx is less than or equal to 50mg / Nm, and the emission of NOx is less than or equal to 50mg / Nm. By accurately controlling the spraying amount and the spraying time of the urea particles, it can be ensured that the concentration of NOx in flue gas is always kept within the range lower than the specified emission standard, the requirements of environmental protection laws and regulations are met, and an efficient and environment-friendly denitration solution is provided for industrial enterprises.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel kiln denitration, and in particular to an anhydrous ammonia denitration device and process. Background Art

[0002] Industrial kilns emit large amounts of nitrogen oxides (NOx) during their high-temperature combustion process, a significant source of air pollution. NOx is not only a major precursor to acid rain and photochemical smog, but also poses a serious threat to the ecological environment and human health. To control the environmental impact of industrial emissions, countries have successively established strict NOx emission limits. In particular, driven by the Air Pollution Prevention and Control Action Plan, many industries are required to meet the Class A NOx emission standard of ≤50mg / Nm³, placing higher demands on the efficiency and adaptability of denitrification technologies.

[0003] Industrial kilns such as tunnel kilns have become key targets for NOx emission control due to their long-term operation, high-temperature combustion, and large flue gas volume. Currently, the mainstream technologies for NOx emission reduction include selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR): SCR technology: It relies on catalysts for reduction reactions. Although the denitrification efficiency is high, the catalyst is expensive and difficult to adapt to the complex working conditions of long tunnel kilns. It is not suitable as a solution for widespread promotion.

[0004] SNCR technology: A reducing agent (such as ammonia or urea) is injected at temperatures between 850°C and 1100°C, reacting with NOx to produce nitrogen and water. Compared to SCR, SNCR requires no catalyst, offers a simpler system, and is less expensive. However, the traditional SNCR process primarily uses liquid reducing agent injection, which presents numerous technical bottlenecks in practical application.

[0005] The application of traditional SNCR technology using liquid reducing agents (such as ammonia or urea solution) in industrial furnaces is limited by the following problems: Uneven spraying: The distribution of liquid reducing agent in the kiln is easily affected by airflow disturbance in the high-temperature area, resulting in incomplete reduction reaction or reduced denitrification efficiency.

[0006] Safety hazards: Liquid reducing agent is volatile and toxic to a certain extent, and there is a risk of leakage during transportation, storage and spraying.

[0007] Poor environmental adaptability: The operating environment of tunnel kilns is characterized by high temperature, high dust, long kiln body and negative pressure conditions, which poses a challenge to the stable operation of traditional liquid injection equipment. Especially under negative pressure conditions, the liquid injection efficiency drops significantly, making it difficult to meet long-term use requirements. Summary of the Invention

[0008] The purpose of the present invention is to provide an anhydrous ammonia denitrification device and process to solve the problems of uneven injection, potential leakage and poor environmental adaptability of the traditional liquid reducing agent injection system proposed in the above background technology.

[0009] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: an anhydrous ammonia denitrification device, comprising a blower chamber and a powder making bin, a circular hopper being installed on the top of the powder making bin, a rotatable disc feeder being provided at the bottom of the circular hopper, a roller mill being provided below the disc feeder, and an ejector being connected below the roller mill.

[0010] Preferably, the roller mill comprises two relatively rotating roller bodies, each of which is provided with a roller shaft, and each of which is provided with a tapered roller bearing rotatably connected to the roller shaft at both ends, and each of which is provided with a first gear fixedly connected to the roller shaft on the outer side. Two roller brushes are provided under the two roller bodies, each of the roller brushes is provided with a roller shaft, both ends of each roller brush are provided with bearings rotatably connected to the roller shaft, and the outer side of each bearing is provided with a second gear fixedly connected to the roller shaft; One of the first gears on each side is meshed with the second gear on the corresponding side through a first chain, and the other first gear on each side is meshed with the third gear arranged on the output end of the second motor through a second chain.

[0011] Preferably, a material receiving hopper is provided below the roller brush, the discharge end of the material receiving hopper is connected to the feed pipe, and the feed pipe is connected to the top of the ejector; The ejector comprises a negative pressure chamber, a contraction chamber, a smoothing chamber, a release chamber and a flow guide chamber from left to right, and an ejection pipe is installed at the air inlet of the negative pressure chamber.

[0012] Preferably, the circular hopper includes a feed hopper, a gathering hopper and a discharge hopper, the feed hopper is fixedly connected to the bottom of the gathering hopper, the discharge hopper is fixedly connected to the bottom of the gathering hopper, the discharge hopper is provided with a discharge port, and the outer wall of the discharge hopper is installed with an arc-shaped baffle for limiting the movement of materials; The disc feeder, arc-shaped baffle and discharge hopper together form a transfer cavity that makes the circular hopper discharge materials evenly, and a material receiving box is provided below the opening of the transfer cavity; The distance between the bottom of the discharge hopper and the disc feeder is 20-40 mm, and the center of the discharge hopper and the center of the disc feeder do not overlap in the vertical direction; The disc feeder further comprises a reducer arranged at the bottom thereof, wherein the reducer is connected to the output end of the first motor; A weight sensor is provided at the bottom of the feed hopper, and a hopper cover is installed at the top of the feed hopper.

[0013] Preferably, an air filter is provided in the fan chamber, and the output end of the air filter is connected to at least two volute fans at the same time, and a check valve is provided on the pipelines at both ends of each volute fan; The output end of each volute fan is connected to the ejector through a DN50 main pipe; Each of the volute fans is provided with a temperature sensor; The DN50 main pipeline is provided with a DN50 vortex flowmeter, a DN50 electric regulating valve and a remote local pressure sensor in sequence; The DN50 main pipeline is also connected in parallel with a DN15 pipeline, and the DN15 pipeline is sequentially provided with a DN15 electric regulating valve and a DN15 vortex flowmeter; The output end of the injector is connected to a six-head distributor, each head of the six-head distributor is connected to a quick-install spray gun through three DN15 pipes, and a DN15 three-way valve is installed at the tail end of the quick-install spray gun.

[0014] An anhydrous ammonia denitrification process comprises the following steps: s1: Filter the air through the air filter to remove moisture and obtain dry air; s2: The dry air is guided into the DN50 main pipe through the volute fan and then into the ejector; S3: The urea material is supplied to the disc feeder through the circular hopper for uniform feeding; s4: Weigh the hopper, disc feeder and incoming materials through weighing sensors; S5: The weighed urea granules enter the roller mill for grinding; S6: The crushed urea granules are introduced into the injector; S7: The injector transports urea granules to the six-head distributor through the dry air introduced into the injector in S2; s8: Six-head distributor distributes urea granules to multiple quick-install spray guns; s9: The quick-install spray gun sprays urea granules into the flue gas flow of the tunnel kiln to carry out the denitrification reaction.

[0015] Preferably, the temperature sensor on the volute fan in step 2 detects that the temperature is greater than 80° and issues an alarm, and switches to another volute fan after a delay of 0-100s. After the switch is completed, the alarm stops; The DN50 main pipeline is equipped with a vortex flowmeter for monitoring flow and a DN50 electric regulating valve for adjusting gas flow over a wide range. The valve can transmit pressure remotely and locally, with a pressure detection range of 0-80KPa and will alarm if the pressure exceeds the range. The DN15 pipeline is provided with a D15 electric regulating valve for adjusting the gas flow in a fine range, and a DN15 vortex flowmeter for monitoring the flow.

[0016] Preferably, the circular hopper in step 3 has a volume of at least 0.15 m3; The disc feeder detects that the kiln temperature exceeds or falls below the set range and alarms, and stops grinding after a delay of 0-100 seconds; The disc feeder determines the nitrogen oxide value by the 4-20mA current signal sent back by the online monitoring data acquisition instrument, and uses the nitrogen oxide value to control the disc feeding frequency. The feeding frequency is increased when the nitrogen oxide value is high, and vice versa.

[0017] Preferably, when the weighing sensor in step 4 weighs less than the set value, an alarm is sounded with a delay of 0-100s, and the total weight is weighed, and the instantaneous reduction and the cumulative reduction are displayed.

[0018] Preferably, the air filter air inlet in step 1 is set in the powder making bin to inhale air, the air inlet is equal to the size of the air filter inlet, and an insulation board is provided between the powder making bin and the fan chamber.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. By setting up a circular hopper and a disc feeder, the accumulation of materials coming out of the hopper can be avoided. Part of the material moves into the transfer cavity through the discharge port. The material moves in the transfer cavity until it falls into the receiving box from the opening of the transfer cavity. Through the above design, the rotation speed of the rotating disk can be controlled by the first motor and the reducer, so that the discharge speed can be freely controlled, and the agglomeration of materials entering from the hopper can be effectively avoided, so that the conveyed materials are more uniform.

[0020] Second, through the setting of the roller mill, the relative rotation of the two rollers can apply shear and compression forces to grind the material into the required particle size. The ground material falls into the receiving hopper, and some materials will stick to the roller body during grinding. The roller brush can brush it off and make all the materials enter the receiving hopper. This can keep the surface of the roller clean and ensure that the material is evenly stressed, and can also avoid the accumulation of powder that causes the roller body to clog.

[0021] 3. Through the mutual cooperation of the fan chamber and the ejector, the ejector pipe can guide the high-speed airflow generated by the volute fan to the ejector, and at the same time rectify and accelerate the airflow, reduce airflow turbulence, and improve the uniformity of the injection. The ejector can inject urea particles into the reaction area of ​​the kiln through a quick-install spray gun. The negative pressure chamber can form a negative pressure inside by the high-speed airflow ejected from the ejector pipe to generate suction, and the urea particles are sucked into the ejector from the receiving hopper and transported to the gathering chamber. The gathering chamber can concentrate and compress the airflow, increase the kinetic energy of the particles carried by the airflow, increase the injection speed, and enhance the particle decomposition efficiency. The smoothing chamber can rectify the airflow passing through the gathering chamber, reduce turbulence, and improve the accuracy of the particle injection direction. The release chamber can increase the pressure of the airflow passing through the smoothing chamber and increase the force of the particle injection.

[0022] In summary, the present invention adopts the anhydrous ammonia process (SNCR) technology. Through the injection of urea granules, a reduction reaction occurs with nitrogen oxides (NOx) in the flue gas to generate nitrogen and water. Compared with the traditional liquid reducing agent injection, the injection of urea granules can effectively reduce the evaporation and diffusion problems of liquid components during the injection process, improve the contact efficiency between the reducing agent and the flue gas, and thus improve the rate of the denitrification reaction and the denitrification efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the process flow of the present invention; Figure 2 It is a schematic diagram of the overall structure of the present invention; Figure 3 It is a schematic diagram of the structure of the air filter and volute fan of the present invention; Figure 4 This is a schematic diagram of the hopper, material receiving box and roller structure of the present invention; Figure 5 It is a schematic diagram of the circular hopper structure of the present invention; Figure 6 Schematic diagram of the cross-sectional structure of the transport cavity of the present invention; Figure 7 It is a structural schematic diagram of the roller mill of the present invention; Figure 8 This is a schematic structural diagram of the material receiving hopper and the material feeding pipe of the present invention; Figure 9 Schematic diagram of the cross-sectional structure of the ejector of the present invention; Figure 10 It is a schematic diagram of the enlarged structure of point A of the present invention.

[0024] Numbers in the figure: 21, air filter; 22, volute fan; 23, check valve; 24, temperature sensor; 31, circular hopper; 311, feed hopper; 312, collection hopper; 313, discharge hopper; 32, hopper cover; 33, discharge port; 34, arc-shaped baffle; 35, disc feeder; 36, transfer chamber; 37, speed reducer; 38, first motor; 39, collection box; 41, roller body; 42, tapered roller bearing; 4 3. First gear; 44. Roller brush; 45. Bearing; 46. Second gear; 47. First chain; 48. Second chain; 49. Third gear; 50. Second motor; 51. Receiving hopper; 52. Feed pipe; 53. Injector; 531. Negative pressure chamber; 532. Retraction chamber; 533. Smoothing chamber; 534. Release chamber; 535. Diversion chamber; 54. Injection pipe; 6. Weight sensor; 9. Display screen; 11. Heat shield. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] See also Figure 1-10 As shown, the present invention provides a technical solution: an anhydrous ammonia denitrification device, comprising a blower chamber and a powder making bin, a circular hopper 31 is installed on the top of the powder making bin, a rotatable disc feeder 35 is provided at the bottom of the circular hopper 31, a roller mill is provided below the disc feeder 35, and an ejector 53 is connected below the roller mill.

[0027] Furthermore, the roller mill includes two roller bodies 41 that rotate relative to each other. A roller shaft is disposed in each roller body 41. Both ends of each roller body 41 are provided with tapered roller bearings 42 that are rotatably connected to the roller shaft. The outer side of each tapered roller bearing 42 is provided with a first gear 43 that is fixedly connected to the roller shaft. Two roller brushes 44 are provided below the two roller bodies 41. Each roller brush 44 is provided with a roller shaft. Both ends of each roller brush 44 are provided with bearings 45 rotatably connected to the roller shaft. The outer side of each bearing 45 is provided with a second gear 46 fixedly connected to the roller shaft. One of the first gears 43 on each side is meshed with the second gear 46 on the corresponding side through a first chain 47 , and the other first gear 43 on each side is meshed with the third gear 49 provided on the output end of the second motor 50 through a second chain 48 .

[0028] The material receiving box 39 can gather the material on the roller body 41, and the two roller bodies 41 are rotated relative to each other to apply shearing and compression forces to grind the material into the required particle size. The ground material falls into the receiving hopper 51, and some of the material will stick to the roller body 41 during grinding. The roller brush 44 can brush it off, so that all the material enters the receiving hopper 51. The tapered roller bearing 42 is used to support the rotation of the roller body 41, reduce the friction generated during the grinding process, and ensure the smooth operation of the roller body 41. A first gear 43 is set on both sides of any roller body 41, and the first gear 43 on one side The third gear 49 is connected to the third gear 49 through the second chain 48, and the third gear 49 is driven to rotate by the second motor 50, thereby driving the second chain 48 to move, and then driving the first gear 43 to rotate, thereby driving the roller body 41 to rotate and grind, and the first gear 43 on the other side is connected to the second gear 46 through the first chain 47. The first gear 43 on the other side drives the second gear 46 to rotate, and the second gear 46 drives the roller brush 44 to rotate, thereby brushing the material off, which can keep the surface of the roller clean and ensure that the material is evenly stressed, and can also avoid powder accumulation causing blockage of the roller body 41.

[0029] Furthermore, a hopper 51 is provided below the roller brush 44 , the discharge end of the hopper 51 is connected to a feed pipe 52 , and the feed pipe 52 is connected to the top of the ejector 53 ; The ejector 53 includes a negative pressure chamber 531 , a contraction chamber 532 , a smoothing chamber 533 , a release chamber 534 and a guide chamber 535 from left to right. The air inlet of the negative pressure chamber 531 is provided with an ejection pipe 54 .

[0030] The inlet diameter of the gathering chamber 532 is larger than the outlet diameter, the inlet diameter of the release chamber 534 is smaller than the outlet diameter, the inlet diameter of the gathering chamber 532 is larger than the outlet diameter of the release chamber 534, and the outlet diameter of the gathering chamber 532 is equal to the inlet diameter of the release chamber 534.

[0031] The negative pressure chamber 531 is fixedly connected to the inlet of the gathering chamber 532 , the diversion chamber 535 is fixedly connected to the outlet of the release chamber 534 , and both ends of the smoothing chamber 533 are fixedly connected to the outlet of the gathering chamber 532 and the inlet of the release chamber 534 , respectively.

[0032] The length of the stowing chamber 532 is shorter than that of the releasing chamber 534 .

[0033] The injection pipe 54 can guide the high-speed airflow generated by the volute fan 22 to the injector 53, and at the same time rectify and accelerate the airflow, reduce airflow turbulence, and improve injection uniformity. The injector 53 can transport urea granules and inject them into the reaction area of ​​the kiln. The negative pressure chamber 531 can form a negative pressure inside by the high-speed airflow ejected from the injection pipe 54 to generate suction, so as to suck the urea granules from the receiving hopper 51 into the injector 53 and transport them to the gathering chamber 532. The gathering chamber 532 can concentrate and compress the airflow, increase the kinetic energy of the airflow carrying the particles, increase the injection speed, and enhance the particle decomposition efficiency. The smoothing chamber 533 can rectify the airflow passing through the gathering chamber 532, reduce turbulence, and improve the accuracy of the particle injection direction. The release chamber 534 can increase the pressure of the airflow passing through the smoothing chamber 533 and increase the force of the particle injection.

[0034] Furthermore, the circular hopper 31 includes a feed hopper 311, a gathering hopper 312, and a discharge hopper 313. The feed hopper 311 is fixedly connected to the gathering hopper 312 below, and the gathering hopper 312 is fixedly connected to the discharge hopper 313 below. The discharge hopper 313 is provided with a discharge port 33, and an arc-shaped baffle 34 is installed on the outer wall of the discharge hopper 313 for limiting the movement of materials. The disc feeder 35, the arc-shaped baffle 34 and the discharge hopper 313 together form a transfer chamber 36 that allows the circular hopper 31 to discharge materials evenly. A material receiving box 39 is provided below the opening of the transfer chamber 36. The distance between the bottom of the discharge hopper 313 and the disc feeder 35 is 20-40 mm, and the center of the discharge hopper 313 does not overlap with the center of the disc feeder 35 in the vertical direction; The disc feeder 35 further includes a reducer 37 disposed at the bottom thereof, and the reducer 37 is connected to the output end of the first motor 38; A weight sensor 6 is provided at the bottom of the feed hopper 311 , and a hopper cover 32 is installed at the top of the feed hopper 311 .

[0035] The hopper 31 can be divided into three parts. The feed hopper 311 is used to allow the material to enter it. The gathering hopper 312 gathers the material and guides it to the discharge hopper 313, and the material falls on the rotating disk 35. The rotating disk 35 is rotated by the reducer 37 and the first motor 38 at the bottom. Since the centers of the rotating disk 35 and the discharge hopper 313 do not coincide in the vertical direction, the material does not fall at the center of the rotating disk 35. Therefore, the material on the rotating disk 35 will move relative to the discharge hopper 313 as the rotating disk 35 rotates, which can avoid the accumulation of material coming out of the discharge hopper 313. Part of the material moves into the transfer chamber 36 through the discharge port 33. The material moves in the transfer chamber 36 until it falls into the receiving box 39 from the opening of the transfer chamber 36. Through the above design, the rotation speed of the rotating disk 35 can be controlled by the first motor 38 and the reducer 37, so that the discharge speed can be freely controlled, and the agglomeration of the material entering from the hopper 31 can be effectively avoided, so that the conveyed material is more uniform.

[0036] Furthermore, an air filter 21 is provided in the fan chamber, and the output end of the air filter 21 is connected to at least two volute fans 22 at the same time, and a check valve 23 is provided on the pipes at both ends of each volute fan 22; The output end of each volute fan 22 is connected to the ejector 53 through a DN50 main pipe; Each volute fan 22 is provided with a temperature sensor 24; The DN50 main pipeline is equipped with a DN50 vortex flowmeter, a DN50 electric regulating valve and a remote local pressure sensor in sequence; The DN50 main pipeline is also connected in parallel with a DN15 pipeline, on which a DN15 electric regulating valve and a DN15 vortex flowmeter are sequentially installed; The output end of the injector 53 is connected to a six-head distributor, each of which is connected to a quick-install spray gun through three DN15 pipes. A DN15 three-way valve is installed at the tail end of the quick-install spray gun.

[0037] The air filter 21 can filter moisture from the external air and allow dry air to enter the volute fan 22 to prevent moisture from contacting with urea particles and forming agglomerates. The volute fan 22 can provide high-speed airflow and provide power to the injector through the DN50 main pipe to ensure that the device evenly transports urea particles to the injector. The DN15 pipe can adjust the flow rate within a fine range through the DN15 electric regulating valve and DN15 vortex flowmeter to make the adjustment range more accurate. The check valve 23 can prevent air flow backflow and protect the pipeline and equipment. The temperature sensor 24 can monitor the volute fan 2 2. When the temperature of the running volute fan 22 reaches the set value, switch to another idle volute fan 22 to prevent the equipment from failing due to high temperature. The six-head distributor can ensure that the material can be evenly distributed to each injection point, avoiding the problem of uneven single-point injection and optimizing the denitrification reaction effect. The quick-install spray gun interface design facilitates quick installation and disassembly, reducing downtime during maintenance and replacement, and improving the maintainability and work efficiency of the system. The DN15 three-way valve can direct the material flow to different injection channels or close a channel as needed, thereby achieving flexible injection control.

[0038] An anhydrous ammonia denitrification device and process comprises the following steps: s1: Filter the air through the air filter 21 to remove moisture and obtain dry air; s2: The dry air is guided into the DN50 main pipe through the volute fan 22 and then into the ejector 53; s3: The urea material is supplied to the disc feeder 35 through the circular hopper 31 for uniform feeding; s4: weighing the hopper, the disc feeder 35 and the incoming material through a weighing sensor; S5: The weighed urea granules enter the roller mill for grinding to 200 mesh; s6: The crushed urea granules are introduced into the injector 53; s7: the injector 53 transports the urea granules to the six-head distributor through the dry air introduced into the injector 53 in s2; s8: Six-head distributor distributes urea granules to multiple quick-install spray guns; s9: The quick-install spray gun sprays urea granules into the flue gas flow of the tunnel kiln to carry out the denitrification reaction.

[0039] The air filter has a filtration area of ​​12.5m 2The filter element size is Φ324 outer diameter, Φ213 inner diameter, length L=880, the volute fan air volume Q=320m³ / h, pressure=500mbar; the disc feeder adopts PLC control, and uses the 4-20mA current signal sent back by the online monitoring data acquisition instrument to display the level of nitrogen oxides. The frequency of the disc feeder is controlled by the level of nitrogen oxides to achieve precise control of nitrogen oxides. The voltage and current of each motor can be displayed on the display 9, and the pressure and flow as well as the hourly average and daily average amount of urea can be displayed. The frequency converter frequency can be adjusted. The kiln temperature is higher than 1100° or lower. At 700°, the alarm is delayed for 0-100S, the grinding is stopped, the disc feeder is stopped after 0-30 minutes, the disc feeder is allowed to start after 0-30 minutes after the volute fan is started, the disc feeder is allowed to start after 0-30 minutes after the roller mill is started, the roller mill is allowed to stop after 0-30 minutes after the disc feeder is stopped, after starting any volute fan, the other volute fan is automatically started after 0-30 minutes after the injection pipeline is monitored to be pressure-free, the powder delivery capacity of the injector is 1-170Kg / h, and the urea density is: 1400-1600m 3 / h, the material-gas ratio is 1.

[0040] Furthermore, in step 2, the temperature sensor 24 on the volute fan 22 detects that the temperature is greater than 80° and issues an alarm. The other volute fan 22 is switched to operate after a delay of 0-100 seconds. After the switch is completed, the alarm stops. The DN50 main pipeline is equipped with a vortex flowmeter for monitoring flow and a DN50 electric regulating valve for adjusting gas flow over a wide range. The valve can transmit pressure remotely and locally, with a pressure detection range of 0-80KPa. If the pressure exceeds the range, an alarm will be issued, and the D50 electric regulating valve will display the opening degree. The DN15 pipeline is equipped with a D15 electric regulating valve for adjusting the gas flow in a fine range, and a DN15 vortex flowmeter for monitoring the flow. The D15 electric regulating valve displays the opening degree.

[0041] Furthermore, in step 3, the volume of the circular hopper 31 is at least 0.15m 3 ; The disc feeder 35 detects that the kiln temperature exceeds or falls below the set range and issues an alarm, delaying 0-100s to stop grinding; The disc feeder 35 uses the 4-20mA current signal sent back by the online monitoring data logger to determine the nitrogen oxide value (50-600mg / Nm³). The nitrogen oxide value is used to control the disc feeding frequency. A high nitrogen oxide value increases the feeding frequency, and vice versa. The feeding frequency can be automatically converted to the disc feeder feeding frequency by manually entering the feeding amount (g).

[0042] Furthermore, in step 4, when the weight of the material in the disc feeder measured by the weighing sensor is lower than the weight corresponding to the nitrogen oxide value, an alarm is sounded with a delay of 0-100s, and the cumulative total weight is weighed, displaying the instantaneous reduction and the cumulative reduction. All data are stored for 1 year.

[0043] Furthermore, in step 1, the air inlet of the air filter 21 is set in the powder making bin to inhale air, the air inlet is equal to the size of the inlet of the air filter 21, and an insulation board 11 is provided between the powder making bin and the fan chamber.

[0044] This process uses widely available urea granules as a reducing agent. Under stable operating conditions, it demonstrates excellent denitrification efficiency, reducing raw emission concentrations from 90mg / Nm³ to below 50mg / Nm³, and even reaching ultra-low emissions of 45mg / Nm³ under certain conditions. It can operate 100% synchronously with the tunnel kiln, ensuring uncompromising kiln stability and output while also minimizing damage to the kiln's cooling, calcining, and drying atmospheres.

[0045] For example, a 3.6-meter-cross-section, integrated baking and firing tunnel kiln produces 210,000 to 220,000 standard bricks daily, with a flue gas volume of 100,000 Nm³ / h. Assuming the calorific value remains at its current level, the equipment operates 24 hours a day, using urea granules with a 46% ammonia nitrogen content as a reducing agent. The hourly consumption is 7 kg, and at a unit price of 2.5 yuan / kg, the daily urea cost is approximately 420 yuan. Furthermore, with a total installed power of 12.95 kW and an actual operating power of 5 kW, the daily electricity bill is 90 yuan, calculated at an electricity price of 0.75 yuan / kWh. This equipment offers low operating costs and ensures stable data and smooth kiln operation over the long term.

[0046] This process can ensure the continuity and stability of kiln production during the denitrification process, and will not cause production reduction, kiln collapse and other phenomena. Under the existing emission standards, it meets or even exceeds the requirements of Class A enterprises.

[0047] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An anhydrous ammonia denitrification device, characterized in that: It comprises a fan chamber and a flour milling bin, wherein a circular hopper (31) is mounted on the top of the flour milling bin, a rotatable disc feeder (35) is arranged at the bottom of the circular hopper (31), a roller mill is arranged below the disc feeder (35), and an ejector (53) is connected to the bottom of the roller mill.

2. The anhydrous ammonia denitrification equipment according to claim 1, characterized in that: The roller mill comprises two roller bodies (41) that rotate relative to each other, each roller body (41) being provided with a roller shaft, both ends of each roller body (41) being provided with tapered roller bearings (42) that are rotatably connected to the roller shaft, and the outer side of each tapered roller bearing (42) being provided with a first gear (43) that is fixedly connected to the roller shaft; Two roller brushes (44) are arranged below the two roller bodies (41), each roller brush (44) is provided with a roller shaft, both ends of each roller brush (44) are provided with bearings (45) rotatably connected to the roller shaft, and the outer side of each bearing (45) is provided with a second gear (46) fixedly connected to the roller shaft; One of the first gears (43) on each side is meshed with the second gear (46) on the corresponding side via a first chain (47), and the other first gear (43) on each side is meshed with the third gear (49) provided on the output end of the second motor (50) via a second chain (48).

3. The anhydrous ammonia denitrification equipment according to claim 2, characterized in that: A material receiving hopper (51) is provided below the rolling brush (44); the material discharge end of the material receiving hopper (51) is connected to a material feeding pipe (52), and the material feeding pipe (52) is connected to the top of the ejector (53); The ejector (53) comprises, from left to right, a negative pressure chamber (531), a contraction chamber (532), a smoothing chamber (533), a release chamber (534), and a flow guiding chamber (535), and an ejection pipe (54) is installed at the air inlet of the negative pressure chamber (531).

4. The anhydrous ammonia denitrification equipment according to claim 1, characterized in that: The circular hopper (31) comprises a feed hopper (311), a gathering hopper (312) and a discharge hopper (313); the feed hopper (311) is fixedly connected to the bottom of the gathering hopper (312); the discharge hopper (313) is fixedly connected to the bottom of the gathering hopper (312); the discharge hopper (313) is provided with a discharge port (33); and the outer wall of the discharge hopper (313) is provided with an arc-shaped baffle (34) for limiting the movement of materials; The disc feeder (35), the arc-shaped baffle (34) and the discharge hopper (313) together form a transfer chamber (36) that enables the circular hopper (31) to discharge materials evenly, and a material receiving box (39) is provided below the opening of the transfer chamber (36); The distance between the bottom of the discharge hopper (313) and the disc feeder (35) is 20-40 mm, and the center of the discharge hopper (313) and the center of the disc feeder (35) do not overlap in the vertical direction; The disc feeder (35) further comprises a reducer (37) arranged at the bottom thereof, wherein the reducer (37) is connected to an output end of the first motor (38); A weight sensor (6) is provided at the bottom of the feed hopper (311), and a hopper cover (32) is installed at the top of the feed hopper (311).

5. The anhydrous ammonia denitrification equipment according to claim 1, characterized in that: An air filter (21) is arranged in the fan chamber, and the output end of the air filter (21) is simultaneously connected to at least two volute fans (22), and a check valve (23) is arranged on the pipelines at both ends of each volute fan (22); The output end of each volute fan (22) is connected to the ejector (53) via a DN50 main pipeline; Each of the volute fans (22) is provided with a temperature sensor (24); The DN50 main pipeline is provided with a DN50 vortex flowmeter, a DN50 electric regulating valve and a remote local pressure sensor in sequence; The DN50 main pipeline is also connected in parallel with a DN15 pipeline, and the DN15 pipeline is sequentially provided with a DN15 electric regulating valve and a DN15 vortex flowmeter; The output end of the injector (53) is connected to a six-head distributor, each head of the six-head distributor is connected to a quick-install spray gun via three DN15 pipes, and a DN15 three-way valve is installed at the rear end of the quick-install spray gun.

6. An anhydrous ammonia denitrification process, using the denitrification equipment according to any one of claims 1 to 5, characterized in that: The steps include: s1: filtering the air through an air filter (21) to remove moisture and obtain dry air; s2: The dry air is guided into the DN50 main pipeline through the volute fan (22) and then into the ejector (53); s3: supplying the urea material to the disc feeder (35) through the circular hopper (31) for uniform feeding; s4: weighing the hopper, the disc feeder (35) and the incoming material through a weighing sensor; S5: The weighed urea particles enter the roller mill for grinding; s6: the crushed urea particles are introduced into the injector (53); s7: the injector (53) conveys the urea granules to the six-head distributor through the dry air introduced into the injector (53) in s2; s8: Six-head distributor distributes urea granules to multiple quick-install spray guns; s9: The quick-loading spray gun sprays urea granules into the flue gas flow of the tunnel kiln to carry out the denitrification reaction.

7. The anhydrous ammonia denitrification process according to claim 6, characterized in that: The temperature sensor (24) on the volute fan (22) in step 2 detects that the temperature is greater than 80° and gives an alarm, and switches to another volute fan (22) for operation after a delay of 0-100 seconds. After the switch is completed, the alarm stops; The vortex flowmeter used to monitor the flow rate on the DN50 main pipeline and the DN50 electric regulating valve used to adjust the gas flow rate over a wide range can transmit the pressure remotely and locally, with a pressure detection range of 0-80KPa and an alarm when the pressure exceeds the range; The DN15 pipeline is provided with a D15 electric regulating valve for adjusting the gas flow in a fine range, and a DN15 vortex flowmeter for monitoring the flow.

8. The anhydrous ammonia denitrification process according to claim 6, characterized in that: The circular hopper (31) in step 3 has a volume of at least 0.15m 3 ; The disc feeder (35) detects that the kiln temperature exceeds or falls below a set range, and issues an alarm, and stops grinding after a delay of 0-100 seconds; The disc feeder (35) determines the nitrogen oxide value by means of the 4-20 mA current signal transmitted back by the online monitoring data acquisition instrument, and uses the nitrogen oxide value to control the disc feeding frequency. When the nitrogen oxide value is high, the feeding frequency is increased, and vice versa, the feeding frequency is reduced.

9. The anhydrous ammonia denitrification process according to claim 6, characterized in that: When the weighing sensor weighs less than the set value in step 4, an alarm is sounded with a delay of 0-100s, and the total accumulated weight is weighed, displaying the instantaneous decrease and the accumulated decrease.

10. The anhydrous ammonia denitrification process according to claim 6, characterized in that: The air inlet of the air filter (21) in step 1 is arranged to inhale air in the flour making bin, the air inlet is equal to the size of the inlet of the air filter (21), and a heat insulation board (11) is arranged between the flour making bin and the fan chamber.

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