A special low-nitrogen combustion equipment and method for heating furnace with self-adjusting flue gas circulation amount

Abstract

The application discloses a kind of special low-nitrogen combustion equipment and method of heating furnace flue gas circulation quantity self-regulation, equipment includes equipment ontology, adjusting assembly being arranged on equipment ontology and the PLC controller being electrically connected with adjusting assembly;Equipment ontology includes shell and the combustion chamber being sleeved in shell;Combustion chamber is equipped with fuel pipe, air inlet pipe and flue gas pipe, and is equipped with oxygen sensor inside;Adjusting assembly includes circulation pipe being connected with combustion chamber, flue gas pipe, adjusting box being sleeved in the outside of circulation pipe, adjusting motor being arranged in adjusting box, threaded rod being clamped in adjusting box inside and sliding valve plate being slidingly clamped in circulation pipe and flue gas pipe inside;PLC controller is electrically connected with each electric equipment respectively;The equipment structure of the application is reasonably designed, the emission of nitride is reduced by real-time dynamic adjustment to flue gas circulation quantity, and it has important significance for environmental protection.

Description

Technical Field

[0001] This invention relates to the field of flue gas treatment technology, specifically to a low-NOx combustion device and method for a heating furnace with self-adjusting flue gas circulation volume. Background Technology

[0002] Boilers and industrial furnaces are the two largest stationary sources of nitrogen oxides (NOx). Their market share, individual unit size, and NOx emissions far exceed those of boilers, making them the largest stationary NOx emission sources currently. However, NOx control in industrial furnaces lacks standards and policy support in terms of environmental management. Industrial furnaces are diverse, and surveys show that many types lack emission standards. Existing standards, though issued earlier, have seen almost no updates in the last three years. The emission limits for most furnaces, such as heating furnaces and heat treatment furnaces, which have a large existing stock, remain high, leaving significant room for reduction. Low-NOx combustion is an integral part of the combustion reaction, with NOx formation primarily consisting of NO and NO2, collectively known as NOx. Many factors influence low-NOx combustion, including temperature, oxygen content, reaction time, and the physical and chemical properties of pulverized coal. Increased oxygen content can create or enhance the oxidizing atmosphere within the furnace, increasing oxygen supply and promoting the conversion of nitrogen (N) in the fuel to NOx. During combustion, NOx in the atmosphere dissolves in water to form nitric acid rain, which causes widespread environmental damage and significant economic losses.

[0003] Nitrogen reduction technology in industrial furnaces still relies on end-of-pipe denitrification, which involves high investment costs, continuous operation, secondary pollution, and no energy-saving benefits. There is an urgent need to explore source control technologies that offer significant emission reduction benefits, low investment, energy savings, and easy management to provide technical support for nitrogen oxide emission reduction in industrial furnaces. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a low-NOx combustion device and method for heating furnaces with self-adjusting flue gas recirculation volume.

[0005] The technical solution of the present invention is as follows: a low-NOx combustion device for a heating furnace with self-adjusting flue gas circulation volume, comprising a device body, an adjustment component disposed on the device body, and a PLC controller electrically connected to the adjustment component; the device body includes an outer shell and a combustion chamber fitted inside the outer shell; an air inlet box is disposed on the side wall of the outer shell, and a centrifugal fan is disposed inside the air inlet box; a fuel pipe and an air inlet pipe penetrating the outer shell are respectively disposed on both sides of the outer wall of the combustion chamber, and the air inlet pipe is connected to the air inlet box; an exhaust pipe penetrating the outer shell is disposed at the top of the combustion chamber; an oxygen sensor is disposed inside the combustion chamber;

[0006] The regulating assembly includes a circulation pipe connected to the air inlet box and the exhaust pipe respectively, an regulating box sleeved on the outside of the circulation pipe via a bracket, a regulating motor installed inside the regulating box, a threaded rod rotatably engaged inside the regulating box, and two sliding valve plates slidably engaged inside the circulation pipe and the exhaust pipe respectively; a return air fan is installed at the connection between the circulation pipe and the exhaust pipe; positioning plates are installed inside the circulation pipe and the exhaust pipe, corresponding to the positions of the sliding valve plates, and each of the two positioning plates is provided with a first exhaust groove; an regulating gear is sleeved on the output shaft of the regulating motor; one end of the threaded rod is fixedly connected to the sliding valve plate inside the exhaust pipe, and the other end passes through the regulating box; a threaded sleeve is sleeved on the end of the threaded rod near the exhaust pipe, which is rotatably engaged with the regulating box, and a first gear ring is sleeved on the threaded sleeve, which meshes with the regulating gear; a rotating sleeve is sleeved on the end of the threaded rod away from the exhaust pipe, which is rotatably engaged with the regulating box, and a second gear ring is sleeved on the rotating sleeve; a second exhaust groove is provided on each of the two sliding valve plates, and a rack is provided on the sliding valve plate inside the circulation pipe, which meshes with the second gear ring;

[0007] The PLC controller is electrically connected to the centrifugal fan, oxygen sensor, regulating motor, and return air fan, respectively.

[0008] Furthermore, the sliding valve plate is slidably engaged inside the circulation pipe via a sliding rod, and both ends of the sliding rod are equipped with compression springs that engage with the inner wall of the circulation pipe.

[0009] Explanation: The sliding rod improves the smoothness of the sliding valve plate's movement inside the circulation pipe; the compression spring ensures that the sliding valve plate always slides in close contact with the positioning plate, preventing flue gas from escaping through the gap between the sliding valve plate and the positioning plate.

[0010] Furthermore, a groove is provided on the positioning plate, and a sealing edge that engages with the groove is provided circumferentially on the lower end face of the sliding valve plate;

[0011] Note: When the sliding valve plate slides on the positioning plate, the sealing edge is always located inside the settling groove, which helps to improve the accuracy and reliability of flue gas circulation volume adjustment.

[0012] Furthermore, a flue gas filter assembly is installed on the exhaust pipe and at the lower end of the connection between the circulation pipe and the exhaust pipe; the flue gas filter assembly includes a cleaning box sleeved on the outside of the exhaust pipe and connected to the outer shell, a filter plate slidably engaged inside the exhaust pipe, cleaning brush sleeves slidably engaged on both sides inside the cleaning box, and a cleaning motor installed on the side wall of the cleaning box and providing power to the cleaning brush sleeves; there are two filter plates arranged horizontally side by side, and a first electric rod connected to the inner wall of the cleaning box is installed on the side wall of one of the filter plates; rotating screws are rotatably engaged on both sides inside the cleaning box and threadedly connected to both ends of the cleaning brush sleeves; the cleaning motor provides power to the rotating screws;

[0013] Explanation: When one of the filter plates becomes clogged and affects the working efficiency of the equipment, the first electric lever is used to push the filter plate to switch the filter plate; at the same time, the cleaning motor drives the rotating screw to rotate, so that the cleaning brush sleeve moves along the inner wall of the cleaning box under the action of the rotating screw, removing contaminants from the surface of the used filter plate, ensuring the continuous and efficient operation of the equipment.

[0014] Furthermore, an air damper is rotatably connected inside the air inlet of the air inlet box via a rotating shaft, and a rotating arm connected to the rotating shaft and a second electric rod connected to the rotating arm are provided on the outer wall of the air inlet box.

[0015] Explanation: The second electric lever drives the rotating arm to rotate, which causes the rotating shaft to shift the air damper at the air inlet of the air box, thereby adjusting the oxygen supply inside the combustion chamber.

[0016] Furthermore, the end of the threaded rod is provided with a positioning head that slides and engages with the adjusting box;

[0017] Note: By setting a positioning head at the end of the threaded rod, the connection stability between the threaded rod and the regulating box can be improved.

[0018] Furthermore, a flame distribution plate is provided inside the combustion chamber, and several flame distribution holes are evenly distributed on the flame distribution plate. The flame distribution holes are frustum-shaped structures with a larger upper part and a smaller lower part.

[0019] Explanation: The flame can be blocked and divided by the flame splitter plate and flame splitting holes, thereby increasing the flame heat dissipation area and reducing the flame temperature, thus reducing the thermal reaction N. X Production decreased.

[0020] Furthermore, a flow divider is provided on the upper surface of the flame divider plate at a position corresponding to each flame divider hole;

[0021] Note: By setting up a flow divider, the flame segmentation effect can be further improved and the flame combustion temperature can be reduced.

[0022] Furthermore, a first baffle is provided on the inner wall of the flame distribution hole, and a second baffle is provided on the inner wall of the flow divider tube. The second baffle and the first baffle are staggered in their upper and lower positions.

[0023] Explanation: During combustion, the flame is divided into multiple smaller flames after passing through the staggered first and second baffles, thus shortening the residence time of gases such as oxygen and nitrogen in the flame and inhibiting the thermal reaction N. X The generation of .

[0024] This invention also provides a low-NOx combustion method for a heating furnace with self-adjusting flue gas recirculation, comprising the following steps:

[0025] S1. Connect the centrifugal fan, regulating motor and return air fan to the external power supply equipment respectively;

[0026] S2. Fuel is introduced into the combustion chamber through the fuel pipe, and the centrifugal fan is started by the PLC controller. Under the action of the centrifugal fan, air enters the combustion chamber through the air intake pipe and mixes with the fuel for combustion. The flue gas generated during the combustion process is discharged through the exhaust pipe.

[0027] S3. The PLC controller controls the start of the regulating motor and return air fan. The regulating motor drives the regulating gear to rotate, which in turn drives the threaded sleeve to rotate. At this time, the threaded rod pulls the sliding valve plate inside the exhaust pipe to move under the action of the threaded sleeve, so that the second exhaust groove inside the exhaust pipe overlaps with the first exhaust groove and closes the exhaust pipe outlet. During the rotation of the rotating sleeve, the second gear ring is driven. The meshing of the second gear ring with the rack causes the sliding valve plate inside the circulation pipe to move. The second exhaust groove inside the circulation pipe is connected to the first exhaust groove, and the flue gas enters the air inlet box through the circulation pipe for secondary combustion.

[0028] S4. The oxygen sensor monitors the oxygen concentration inside the combustion chamber in real time. When the oxygen concentration inside the combustion chamber is lower than the set value, the PLC controller controls the regulating motor to reverse. This causes the second exhaust trough inside the exhaust pipe to gradually connect with the first exhaust trough, while the second exhaust trough inside the circulation pipe gradually overlaps with the first exhaust trough, reducing the amount of flue gas circulating.

[0029] S5. Repeat steps S3 and S4 to achieve dynamic adjustment of flue gas recirculation volume.

[0030] Compared with the prior art, the beneficial effects of the present invention are reflected in the following aspects:

[0031] First, the device structure of the present invention is reasonably designed. By adjusting the flue gas circulation volume entering the combustion chamber in real time, the oxygen concentration in the combustion chamber is kept constant, thereby reducing the partial pressure of oxygen and weakening the process of generating thermal NOx from oxygen and nitrogen, thus reducing NOx generation, which is of great significance for environmental protection.

[0032] Secondly, the equipment of the present invention intercepts and filters large particulate impurities in flue gas through flue gas filtration components, avoiding corrosion and clogging of the equipment by impurities in the flue gas, improving the operational stability of the equipment and extending the service life of the burner.

[0033] Third, this invention utilizes the synergistic effect of the flame divider and the flow divider to segment and divert the combustion flame, thereby increasing the flame heat dissipation area and reducing the flame temperature, thus improving the thermal reaction N X The yield is reduced; at the same time, the flame is divided into multiple smaller flames, shortening the residence time of gases such as oxygen and nitrogen in the flame, and inhibiting the thermal reaction N. X The generation of . Attached Figure Description

[0034] Figure 1 This is a longitudinal sectional view of the device of the present invention;

[0035] Figure 2 This is a front view of the device of the present invention;

[0036] Figure 3 This is the present invention. Figure 2 A magnified view of a portion of point A;

[0037] Figure 4 This is a schematic diagram of the structure of the adjustment component of the present invention;

[0038] Figure 5 This is a schematic diagram of the connection between the sliding valve plate and the exhaust pipe of the present invention;

[0039] Figure 6 This is a schematic diagram of the connection between the sliding valve plate and the positioning plate of the present invention;

[0040] Figure 7 This is a schematic diagram showing the connection between the flue gas filter assembly and the exhaust pipe of the present invention;

[0041] Figure 8 This is a schematic diagram showing the connection between the cleaning brush sleeve and the filter plate of the present invention;

[0042] Figure 9 This is a schematic diagram of the connection between the flow divider and the flame distribution plate of the present invention;

[0043] Among them, 1-equipment body, 10-outer shell, 11-combustion chamber, 110-fuel pipe, 111-intake pipe, 112-exhaust pipe, 12-air inlet box, 120-rotating shaft, 121-damper, 122-rotating arm, 123-second electric rod, 13-centrifugal fan, 2-adjusting assembly, 20-circulation pipe, 21-adjusting box, 210-support, 22-adjusting motor, 220-adjusting gear, 23-threaded rod, 230-threaded sleeve, 231-first gear ring, 232-rotating sleeve, 233-second gear ring, 2 34-Positioning head, 24-Sliding valve plate, 240-Second exhaust trough, 241-Rack, 242-Sliding rod, 243-Compression spring, 244-Sealing edge, 25-Return air fan, 26-Positioning plate, 260-First exhaust trough, 261-Settling trough, 3-Fluorescence filter assembly, 30-Cleaning box, 31-Filter plate, 32-Cleaning brush sleeve, 33-Cleaning motor, 34-First electric rod, 35-Rotating screw, 4-Flame distribution plate, 40-Flame distribution hole, 400-First baffle, 41-Diverter pipe, 410-Second baffle. Detailed Implementation

[0044] Example 1

[0045] like Figure 1The diagram shows a low-NOx combustion device for a heating furnace with self-adjusting flue gas circulation volume. It includes a device body 1, an adjustment component 2 mounted on the device body 1, and a PLC controller electrically connected to the adjustment component 2. The device body 1 includes an outer shell 10 and a combustion chamber 11 housed within the outer shell 10. An air inlet box 12 is mounted on the side wall of the outer shell 10, and a centrifugal fan 13 is installed inside the air inlet box 12. Fuel pipes 110 and air inlet pipes 111, penetrating the outer shell 10, are respectively mounted on both sides of the outer wall of the combustion chamber 11, with the air inlet pipes 111 communicating with the air inlet box 12. An exhaust pipe 112, penetrating the outer shell 10, is mounted at the top of the combustion chamber 11. An oxygen sensor is installed inside the combustion chamber 11.

[0046] like Figure 1 , 4 As shown in Figures 5 and 6, the regulating assembly 2 includes a circulation pipe 20 connected to the air inlet box 12 and the exhaust pipe 112 respectively, an regulating box 21 sleeved on the outside of the circulation pipe 20 via a bracket 210, a regulating motor 22 disposed inside the regulating box 21, a threaded rod 23 rotatably engaged inside the regulating box 21, and two sliding valve plates 24 respectively slidably engaged inside the circulation pipe 20 and the exhaust pipe 112; a return air fan 25 is provided at the connection between the circulation pipe 20 and the exhaust pipe 112; positioning plates 26 are provided inside the circulation pipe 20 and the exhaust pipe 112 at positions corresponding to the sliding valve plates 24, and a first exhaust groove 260 is provided on each of the two positioning plates 26; an regulating motor 22 is sleeved on the output shaft of the regulating motor 22. A gear 220 is used; one end of a threaded rod 23 is fixedly connected to a sliding valve plate 24 inside the exhaust pipe 112, and the other end passes through the regulating box 21; a threaded sleeve 230 is fitted on the end of the threaded rod 23 near the exhaust pipe 112, which is rotatably engaged with the regulating box 21, and a first gear ring 231 is fitted on the threaded sleeve 230, which meshes with the regulating gear 220; a rotating sleeve 232 is fitted on the end of the threaded rod 23 away from the exhaust pipe 112, which is rotatably engaged with the regulating box 21, and a second gear ring 233 is fitted on the rotating sleeve 232; a second exhaust groove 240 is provided on both sliding valve plates 24, and a rack 241 is provided on the sliding valve plate 24 inside the circulation pipe 20, which meshes with the second gear ring 233;

[0047] like Figure 1 As shown, the PLC controller is electrically connected to the centrifugal fan 13, the oxygen sensor, the regulating motor 22, and the return air fan 25.

[0048] Example 2

[0049] This embodiment describes a method for self-adjusting flue gas recirculation volume using the low-NOx combustion equipment of Embodiment 1, including the following steps:

[0050] S1. Connect the centrifugal fan 13, the regulating motor 22 and the return air fan 25 to the external power supply equipment respectively;

[0051] S2. Fuel is introduced into the combustion chamber 11 through fuel pipe 110, and centrifugal fan 13 is started by PLC controller. Under the action of centrifugal fan 13, air enters the combustion chamber 11 through air intake pipe 111 and mixes with fuel for combustion. The flue gas generated during combustion is discharged through exhaust pipe 112.

[0052] S3. The PLC controller starts the regulating motor 22 and the return air fan 25. The regulating motor 22 drives the regulating gear 220 to rotate, which in turn drives the threaded sleeve 230 to rotate through the first gear ring 231. At this time, the threaded rod 23 pulls the sliding valve plate 24 inside the exhaust pipe 112 to move under the action of the threaded sleeve 230, so that the second exhaust groove 240 and the first exhaust groove 260 inside the exhaust pipe 112 overlap and close the outlet of the exhaust pipe 112. During the rotation of the rotating sleeve 232, the second gear ring 233 is driven. The meshing action of the second gear ring 233 and the rack 241 causes the sliding valve plate 24 inside the circulation pipe 20 to move. The second exhaust groove 240 and the first exhaust groove 260 inside the circulation pipe 20 are interconnected, and the flue gas enters the air inlet box 12 through the circulation pipe 20 for secondary combustion.

[0053] S4. The oxygen concentration inside the combustion chamber 11 is monitored in real time using an oxygen sensor. When the oxygen concentration inside the combustion chamber 11 is lower than the set value, the regulating motor 22 is reversed by the PLC controller. This causes the second exhaust groove 240 inside the exhaust pipe 112 to gradually connect with the first exhaust groove 260, while the second exhaust groove 240 inside the circulation pipe 20 gradually overlaps with the first exhaust groove 260, thereby reducing the amount of flue gas circulating.

[0054] S5. Repeat steps S3 and S4 to achieve automatic adjustment of flue gas recirculation volume.

[0055] Example 3

[0056] like Figure 1 The diagram shows a low-NOx combustion device for a heating furnace with self-adjusting flue gas circulation volume. It includes a device body 1, an adjustment component 2 mounted on the device body 1, and a PLC controller electrically connected to the adjustment component 2. The device body 1 includes an outer shell 10 and a combustion chamber 11 housed within the outer shell 10. An air inlet box 12 is mounted on the side wall of the outer shell 10, and a centrifugal fan 13 is installed inside the air inlet box 12. Fuel pipes 110 and air inlet pipes 111, penetrating the outer shell 10, are respectively mounted on both sides of the outer wall of the combustion chamber 11, with the air inlet pipes 111 communicating with the air inlet box 12. An exhaust pipe 112, penetrating the outer shell 10, is mounted at the top of the combustion chamber 11. An oxygen sensor is installed inside the combustion chamber 11.

[0057] like Figure 2 , 4As shown in Figures 5 and 6, the regulating assembly 2 includes a circulation pipe 20 connected to the air inlet box 12 and the exhaust pipe 112 respectively, an regulating box 21 sleeved on the outside of the circulation pipe 20 via a bracket 210, a regulating motor 22 disposed inside the regulating box 21, a threaded rod 23 rotatably engaged inside the regulating box 21, and two sliding valve plates 24 respectively slidably engaged inside the circulation pipe 20 and the exhaust pipe 112; a return air fan 25 is provided at the connection between the circulation pipe 20 and the exhaust pipe 112; positioning plates 26 are provided inside the circulation pipe 20 and the exhaust pipe 112 at positions corresponding to the sliding valve plates 24, and each of the two positioning plates 26 is provided with a first exhaust groove 260; an regulating gear 220 is sleeved on the output shaft of the regulating motor 22; one end of the threaded rod 23 is fixedly connected to the sliding valve plate 24 inside the exhaust pipe 112, and the other end passes through the regulating box 21; the threaded rod 23 is close to One end of the exhaust pipe 112 is fitted with a threaded sleeve 230 that is rotatably engaged with the regulating box 21. A first gear ring 231 that meshes with the regulating gear 220 is fitted on the threaded sleeve 230. The end of the threaded rod 23 away from the exhaust pipe 112 is fitted with a rotating sleeve 232 that is rotatably engaged with the regulating box 21. A second gear ring 233 is fitted on the rotating sleeve 232. Both sliding valve plates 24 are provided with second exhaust grooves 240. The sliding valve plate 24 inside the circulation pipe 20 is provided with a rack 241 that meshes with the second gear ring 233. The sliding valve plate 24 is slidably engaged with the inside of the circulation pipe 20 by a sliding rod 242. Both ends of the sliding rod 242 are provided with compression springs 243 that engage with the inner wall of the circulation pipe 20. The positioning plate 26 is provided with a groove 261. The lower end face of the sliding valve plate 24 is provided with a sealing edge 244 that engages with the groove 261.

[0058] like Figure 1 As shown, the PLC controller is electrically connected to the centrifugal fan 13, the oxygen sensor, the regulating motor 22, and the return air fan 25.

[0059] Example 4

[0060] This embodiment describes a method for self-adjusting flue gas recirculation using the low-NOx combustion equipment of Embodiment 3, including the following steps:

[0061] S1. Connect the centrifugal fan 13, the regulating motor 22 and the return air fan 25 to the external power supply equipment respectively;

[0062] S2. Fuel is introduced into the combustion chamber 11 through fuel pipe 110, and centrifugal fan 13 is started by PLC controller. Under the action of centrifugal fan 13, air enters the combustion chamber 11 through air intake pipe 111 and mixes with fuel for combustion. The flue gas generated during combustion is discharged through exhaust pipe 112.

[0063] S3. The PLC controller starts the regulating motor 22 and the return air fan 25. The regulating motor 22 drives the regulating gear 220 to rotate, which in turn drives the threaded sleeve 230 to rotate through the first gear ring 231. At this time, the threaded rod 23 pulls the sliding valve plate 24 inside the exhaust pipe 112 to move under the action of the threaded sleeve 230, so that the second exhaust groove 240 and the first exhaust groove 260 inside the exhaust pipe 112 overlap and close the outlet of the exhaust pipe 112. During the rotation of the rotating sleeve 232, the second gear ring 233 is driven. The meshing action of the second gear ring 233 and the rack 241 causes the sliding valve plate 24 inside the circulation pipe 20 to move. The second exhaust groove 240 and the first exhaust groove 260 inside the circulation pipe 20 are interconnected, and the flue gas enters the air inlet box 12 through the circulation pipe 20 for secondary combustion.

[0064] S4. The oxygen concentration inside the combustion chamber 11 is monitored in real time using an oxygen sensor. When the oxygen concentration inside the combustion chamber 11 is lower than the set value, the regulating motor 22 is reversed by the PLC controller. This causes the second exhaust groove 240 inside the exhaust pipe 112 to gradually connect with the first exhaust groove 260, while the second exhaust groove 240 inside the circulation pipe 20 gradually overlaps with the first exhaust groove 260, thereby reducing the amount of flue gas circulating.

[0065] S5. Repeat steps S3 and S4 to achieve dynamic adjustment of flue gas recirculation volume.

[0066] Example 5

[0067] like Figure 1 The diagram shows a low-NOx combustion device for a heating furnace with self-adjusting flue gas circulation volume. It includes a device body 1, an adjustment component 2 mounted on the device body 1, and a PLC controller electrically connected to the adjustment component 2. The device body 1 includes an outer shell 10 and a combustion chamber 11 housed within the outer shell 10. An air inlet box 12 is mounted on the side wall of the outer shell 10, and a centrifugal fan 13 is installed inside the air inlet box 12. Fuel pipes 110 and air inlet pipes 111, penetrating the outer shell 10, are respectively mounted on both sides of the outer wall of the combustion chamber 11, with the air inlet pipes 111 communicating with the air inlet box 12. An exhaust pipe 112, penetrating the outer shell 10, is mounted at the top of the combustion chamber 11. An oxygen sensor is installed inside the combustion chamber 11.

[0068] like Figure 2 , 4As shown in Figures 5 and 6, the regulating assembly 2 includes a circulation pipe 20 connected to the air inlet box 12 and the exhaust pipe 112 respectively, an regulating box 21 sleeved on the outside of the circulation pipe 20 via a bracket 210, a regulating motor 22 disposed inside the regulating box 21, a threaded rod 23 rotatably engaged inside the regulating box 21, and two sliding valve plates 24 respectively slidably engaged inside the circulation pipe 20 and the exhaust pipe 112; a return air fan 25 is provided at the connection between the circulation pipe 20 and the exhaust pipe 112; positioning plates 26 are provided inside the circulation pipe 20 and the exhaust pipe 112 at positions corresponding to the sliding valve plates 24, and each of the two positioning plates 26 is provided with a first exhaust groove 260; an regulating gear 220 is sleeved on the output shaft of the regulating motor 22; one end of the threaded rod 23 is fixedly connected to the sliding valve plate 24 inside the exhaust pipe 112, and the other end passes through the regulating box 21; the threaded rod 23 is close to One end of the exhaust pipe 112 is fitted with a threaded sleeve 230 that is rotatably engaged with the regulating box 21. A first gear ring 231 that meshes with the regulating gear 220 is fitted on the threaded sleeve 230. The end of the threaded rod 23 away from the exhaust pipe 112 is fitted with a rotating sleeve 232 that is rotatably engaged with the regulating box 21. A second gear ring 233 is fitted on the rotating sleeve 232. Both sliding valve plates 24 are provided with second exhaust grooves 240. The sliding valve plate 24 inside the circulation pipe 20 is provided with a rack 241 that meshes with the second gear ring 233. The sliding valve plate 24 is slidably engaged with the inside of the circulation pipe 20 by a sliding rod 242. Both ends of the sliding rod 242 are provided with compression springs 243 that engage with the inner wall of the circulation pipe 20. The positioning plate 26 is provided with a groove 261. The lower end face of the sliding valve plate 24 is provided with a sealing edge 244 that engages with the groove 261.

[0069] like Figure 1 , 7 As shown in Figure 8, a flue gas filter assembly 3 is provided on the exhaust pipe 112 and at the lower end of the connection between the circulation pipe 20 and the exhaust pipe 112. The flue gas filter assembly 3 includes a cleaning box 30 sleeved on the outside of the exhaust pipe 112 and connected to the outer shell 10, a filter plate 31 slidably engaged inside the exhaust pipe 112, a cleaning brush sleeve 32 slidably engaged on both sides inside the cleaning box 30, and a cleaning motor 33 provided on the side wall of the cleaning box 30 and providing power to the cleaning brush sleeve 32. There are two filter plates 31 arranged horizontally side by side, and a first electric rod 34 connected to the inner wall of the cleaning box 30 is provided on the side wall of one of the filter plates 31. Rotary screws 35 are rotatably engaged on both sides inside the cleaning box 30 and threadedly connected to both ends of the cleaning brush sleeve 32. The cleaning motor 33 provides power to the rotating screws 35.

[0070] like Figure 1 As shown, the PLC controller is electrically connected to the centrifugal fan 13, oxygen sensor, regulating motor 22, return air fan 25, cleaning motor 33 and first electric rod 34 respectively.

[0071] Example 6

[0072] This embodiment describes a method for self-adjusting flue gas recirculation using the low-NOx combustion equipment of Embodiment 5, including the following steps:

[0073] S1. Connect the centrifugal fan 13, regulating motor 22, return air fan 25, cleaning motor 33 and first electric rod 34 to the external power supply equipment respectively;

[0074] S2. Fuel is introduced into the combustion chamber 11 through fuel pipe 110, and centrifugal fan 13 is started by PLC controller. Under the action of centrifugal fan 13, air enters the combustion chamber 11 through air intake pipe 111 and mixes with fuel for combustion. The flue gas generated during combustion is discharged through exhaust pipe 112.

[0075] S3. The PLC controller starts the regulating motor 22 and the return air fan 25. The regulating motor 22 drives the regulating gear 220 to rotate, which in turn drives the threaded sleeve 230 to rotate through the first gear ring 231. At this time, the threaded rod 23 pulls the sliding valve plate 24 inside the exhaust pipe 112 to move under the action of the threaded sleeve 230, so that the second exhaust groove 240 and the first exhaust groove 260 inside the exhaust pipe 112 overlap and close the outlet of the exhaust pipe 112. During the rotation of the rotating sleeve 232, the second gear ring 233 is driven. The meshing action of the second gear ring 233 and the rack 241 causes the sliding valve plate 24 inside the circulation pipe 20 to move. The second exhaust groove 240 and the first exhaust groove 260 inside the circulation pipe 20 are interconnected, and the flue gas enters the air inlet box 12 through the circulation pipe 20 for secondary combustion.

[0076] S4. The oxygen concentration inside the combustion chamber 11 is monitored in real time using an oxygen sensor. When the oxygen concentration inside the combustion chamber 11 is lower than the set value, the regulating motor 22 is reversed by the PLC controller. This causes the second exhaust groove 240 inside the exhaust pipe 112 to gradually connect with the first exhaust groove 260, while the second exhaust groove 240 inside the circulation pipe 20 gradually overlaps with the first exhaust groove 260, thereby reducing the amount of flue gas circulating.

[0077] S5. Repeat steps S3 and S4 to achieve dynamic adjustment of flue gas recirculation volume.

[0078] S6. When one of the filter plates 31 becomes clogged and affects the working efficiency of the equipment, the first electric lever 34 is started by the PLC control, and the first electric lever 34 pushes the filter plate 31 to realize the switching of the filter plate 31; at the same time, the cleaning motor 33 is started by the PLC controller, and the cleaning motor 33 drives the rotating screw 35 to rotate, so that the cleaning brush sleeve 32 moves along the inner wall of the cleaning box 30 under the action of the rotating screw 35 to clean the contaminants on the surface of the filter plate 31.

[0079] Example 7

[0080] like Figure 1 , 3 A low-NOx combustion device for a heating furnace with self-adjusting flue gas circulation volume, as shown in Figure 9, includes a device body 1, an adjustment component 2 mounted on the device body 1, and a PLC controller electrically connected to the adjustment component 2. The device body 1 includes an outer shell 10 and a combustion chamber 11 housed inside the outer shell 10. An air inlet box 12 is provided on the side wall of the outer shell 10, and a centrifugal fan 13 is installed inside the air inlet box 12. A fuel pipe 110 and an air inlet pipe 111, which penetrate the outer shell 10, are respectively provided on both sides of the outer wall of the combustion chamber 11, and the air inlet pipe 111 is connected to the air inlet box 12. An exhaust pipe 112, which penetrates the outer shell 10, is provided at the top of the combustion chamber 11. An oxygen transfer device is installed inside the combustion chamber 11. The air inlet of the air inlet box 12 is rotatably connected to the damper 121 via a rotating shaft 120. The outer wall of the air inlet box 12 is provided with a rotating arm 122 connected to the rotating shaft 120 and a second electric rod 123 connected to the rotating arm 122. The combustion chamber 11 is provided with a flame distribution plate 4. Several flame distribution holes 40 are evenly distributed on the flame distribution plate 4. The flame distribution holes 40 are frustum structures with a larger upper part and a smaller lower part. A diversion pipe 41 is provided on the upper end face of the flame distribution plate 4 and at the position corresponding to each flame distribution hole 40. A first baffle 400 is provided on the inner wall of the flame distribution hole 40, and a second baffle 410 is provided on the inner wall of the diversion pipe 41. The second baffle 410 and the first baffle 400 are staggered vertically.

[0081] like Figure 2 , 4As shown in Figures 5 and 6, the regulating assembly 2 includes a circulation pipe 20 connected to the air inlet box 12 and the exhaust pipe 112 respectively; an regulating box 21 sleeved on the outside of the circulation pipe 20 via a bracket 210; a regulating motor 22 disposed inside the regulating box 21; a threaded rod 23 rotatably engaged inside the regulating box 21; and two sliding valve plates 24 slidably engaged inside the circulation pipe 20 and the exhaust pipe 112 respectively. A return air fan 25 is provided at the connection between the circulation pipe 20 and the exhaust pipe 112. Positioning plates 26 are provided inside the circulation pipe 20 and the exhaust pipe 112 at positions corresponding to the sliding valve plates 24, and each of the two positioning plates 26 is provided with a first exhaust groove 260. An regulating gear 220 is sleeved on the output shaft of the regulating motor 22. One end of the threaded rod 23 is fixedly connected to the sliding valve plate 24 inside the exhaust pipe 112, and the other end passes through the regulating box 21. The end of the threaded rod 23 near the exhaust pipe 112 is sleeved with a... The regulating box 21 is rotatably engaged with a threaded sleeve 230, on which a first gear ring 231 meshes with the regulating gear 220; the end of the threaded rod 23 away from the exhaust pipe 112 is fitted with a rotating sleeve 232 that rotatably engages with the regulating box 21, and a second gear ring 233 is fitted on the rotating sleeve 232; the end of the threaded rod 23 is provided with a positioning head 234 that slidably engages with the regulating box 21; both sliding valve plates 24 are provided with second exhaust grooves 240; the sliding valve plate 24 inside the circulation pipe 20 is provided with a rack 241 that meshes with the second gear ring 233; the sliding valve plate 24 is slidably engaged with the inside of the circulation pipe 20 by a sliding rod 242, and both ends of the sliding rod 242 are provided with compression springs 243 that engage with the inner wall of the circulation pipe 20; the positioning plate 26 is provided with a recess 261, and the lower end face of the sliding valve plate 24 is provided with a sealing edge 244 that engages with the recess 261;

[0082] like Figure 1 , 7 As shown in Figure 8, a flue gas filter assembly 3 is provided on the exhaust pipe 112 and at the lower end of the connection between the circulation pipe 20 and the exhaust pipe 112. The flue gas filter assembly 3 includes a cleaning box 30 sleeved on the outside of the exhaust pipe 112 and connected to the outer shell 10, a filter plate 31 slidably engaged inside the exhaust pipe 112, a cleaning brush sleeve 32 slidably engaged on both sides inside the cleaning box 30, and a cleaning motor 33 provided on the side wall of the cleaning box 30 and providing power to the cleaning brush sleeve 32. There are two filter plates 31 arranged horizontally side by side, and a first electric rod 34 connected to the inner wall of the cleaning box 30 is provided on the side wall of one of the filter plates 31. Rotary screws 35 are rotatably engaged on both sides inside the cleaning box 30 and threadedly connected to both ends of the cleaning brush sleeve 32. The cleaning motor 33 provides power to the rotating screws 35.

[0083] like Figure 1As shown, the PLC controller is electrically connected to the centrifugal fan 13, oxygen sensor, regulating motor 22, return air fan 25, cleaning motor 33, first electric rod 34 and second electric rod 123 respectively.

[0084] Example 8

[0085] This embodiment describes a method for self-adjusting flue gas recirculation volume using the low-NOx combustion equipment of Embodiment 7, including the following steps:

[0086] S1. Connect the centrifugal fan 13, regulating motor 22, return air fan 25, cleaning motor 33 and first electric rod 34 to the external power supply equipment respectively;

[0087] S2. Fuel is introduced into the combustion chamber 11 through fuel pipe 110, and centrifugal fan 13 is started by PLC controller. Under the action of centrifugal fan 13, air enters the combustion chamber 11 through air intake pipe 111 and mixes with fuel for combustion. The flue gas generated during combustion is discharged through exhaust pipe 112. The second electric lever 123 is started by PLC controller, which drives the rotating arm 122 to rotate, thereby causing the rotating shaft 120 to drive the damper 121 to deflect at the air inlet of the air box 12, thus regulating the oxygen supply inside the combustion chamber 11. The combustion flame is blocked and divided by the flame splitting holes 40 and the diversion pipe 41 on the flame splitting plate 4, reducing the flame combustion temperature, shortening the residence time of oxygen, nitrogen and other gases in the flame, and inhibiting the thermal reaction N. X The generation of;

[0088] S3. The PLC controller starts the regulating motor 22 and the return air fan 25. The regulating motor 22 drives the regulating gear 220 to rotate, which in turn drives the threaded sleeve 230 to rotate through the first gear ring 231. At this time, the threaded rod 23 pulls the sliding valve plate 24 inside the exhaust pipe 112 to move under the action of the threaded sleeve 230, so that the second exhaust groove 240 and the first exhaust groove 260 inside the exhaust pipe 112 overlap and close the outlet of the exhaust pipe 112. During the rotation of the rotating sleeve 232, the second gear ring 233 is driven. The meshing action of the second gear ring 233 and the rack 241 causes the sliding valve plate 24 inside the circulation pipe 20 to move. The second exhaust groove 240 and the first exhaust groove 260 inside the circulation pipe 20 are interconnected, and the flue gas enters the air inlet box 12 through the circulation pipe 20 for secondary combustion.

[0089] S4. The oxygen concentration inside the combustion chamber 11 is monitored in real time using an oxygen sensor. When the oxygen concentration inside the combustion chamber 11 is lower than the set value, the regulating motor 22 is reversed by the PLC controller. This causes the second exhaust groove 240 inside the exhaust pipe 112 to gradually connect with the first exhaust groove 260, while the second exhaust groove 240 inside the circulation pipe 20 gradually overlaps with the first exhaust groove 260, thereby reducing the amount of flue gas circulating.

[0090] S5. Repeat steps S3 and S4 to achieve dynamic adjustment of flue gas recirculation volume.

[0091] S6. When one of the filter plates 31 becomes clogged and affects the working efficiency of the equipment, the first electric lever 34 is started by the PLC control, and the first electric lever 34 pushes the filter plate 31 to realize the switching of the filter plate 31; at the same time, the cleaning motor 33 is started by the PLC controller, and the cleaning motor 33 drives the rotating screw 35 to rotate, so that the cleaning brush sleeve 32 moves along the inner wall of the cleaning box 30 under the action of the rotating screw 35 to clean the contaminants on the surface of the filter plate 31.

[0092] It should be noted that the second electric rod 123, centrifugal fan 13, regulating motor 22, return air fan 25 oxygen sensor, cleaning motor 33, first electric rod 34 and PLC controller used in this invention all adopt existing technology and are not specifically limited here. Appropriate products can be selected according to actual needs.

Claims

1. A low-NOx combustion device for a heating furnace with self-adjusting flue gas recirculation volume, characterized in that, The device includes a main body (1), an adjustment assembly (2) mounted on the main body (1), and a PLC controller electrically connected to the adjustment assembly (2). The main body (1) includes an outer shell (10) and a combustion chamber (11) housed inside the outer shell (10). An air inlet box (12) is provided on the side wall of the outer shell (10), and a centrifugal fan (13) is provided inside the air inlet box (12). A fuel pipe (110) and an air inlet pipe (111) penetrating the outer shell (10) are respectively provided on both sides of the outer wall of the combustion chamber (11), and the air inlet pipe (111) is connected to the air inlet box (12). The top of the combustion chamber (11) is... An exhaust pipe (112) penetrating the outer casing (10) is provided at one end; an oxygen sensor is provided inside the combustion chamber (11); the regulating assembly (2) includes a circulation pipe (20) connected to the air inlet box (12) and the exhaust pipe (112) respectively, an regulating box (21) sleeved on the outside of the circulation pipe (20) by a bracket (210), an regulating motor (22) provided inside the regulating box (21), a threaded rod (23) rotatably engaged inside the regulating box (21), and two sliding valve plates (24) slidably engaged inside the circulation pipe (20) and the exhaust pipe (112) respectively; at the connection between the circulation pipe (20) and the exhaust pipe (112) A return air fan (25) is provided; positioning plates (26) are provided inside the circulation pipe (20) and the smoke exhaust pipe (112) at positions corresponding to the sliding valve plate (24), and each of the two positioning plates (26) is provided with a first smoke exhaust groove (260); an adjusting gear (220) is sleeved on the output shaft of the adjusting motor (22); one end of the threaded rod (23) is fixedly connected to the sliding valve plate (24) inside the smoke exhaust pipe (112), and the other end passes through the adjusting box (21); a threaded sleeve (230) is sleeved on the end of the threaded rod (23) near the smoke exhaust pipe (112) and rotates and engages with the adjusting box (21), and the threaded sleeve (230) The upper part is fitted with a first gear ring (231) that meshes with the adjusting gear (220); the end of the threaded rod (23) away from the exhaust pipe (112) is fitted with a rotating sleeve (232) that rotates and engages with the adjusting box (21), and the rotating sleeve (232) is fitted with a second gear ring (233); the two sliding valve plates (24) are each provided with a second exhaust groove (240), and the sliding valve plate (24) inside the circulation pipe (20) is provided with a rack (241) that meshes with the second gear ring (233); the PLC controller is electrically connected to the centrifugal fan (13), oxygen sensor, adjusting motor (22) and return air fan (25) respectively.

2. The low-NOx combustion device for a heating furnace with self-adjusting flue gas circulation volume according to claim 1, characterized in that, The sliding valve plate (24) is slidably engaged inside the circulation pipe (20) by a sliding rod (242), and both ends of the sliding rod (242) are provided with compression springs (243) that engage with the inner wall of the circulation pipe (20).

3. The low-NOx combustion device for a heating furnace with self-adjusting flue gas circulation volume according to claim 1, characterized in that, The positioning plate (26) is provided with a groove (261), and the lower end face of the sliding valve plate (24) is provided with a sealing edge (244) that engages with the groove (261).

4. The low-NOx combustion device for a heating furnace with self-adjusting flue gas circulation volume according to claim 1, characterized in that, A flue gas filter assembly (3) is provided on the exhaust pipe (112) and at the lower end of the connection between the circulation pipe (20) and the exhaust pipe (112). The flue gas filter assembly (3) includes a cleaning box (30) sleeved on the outside of the exhaust pipe (112) and connected to the outer shell (10), a filter plate (31) slidably engaged inside the exhaust pipe (112), a cleaning brush sleeve (32) slidably engaged on both sides inside the cleaning box (30), and a cleaning motor (33) provided on the side wall of the cleaning box (30) and providing power to the cleaning brush sleeve (32). There are two filter plates (31) arranged horizontally side by side. A first electric rod (34) is provided on the side wall of one of the filter plates (31) and connected to the inner wall of the cleaning box (30). Rotary screws (35) are rotatably engaged on both sides inside the cleaning box (30) and threadedly connected to both ends of the cleaning brush sleeve (32). The cleaning motor (33) provides power to the rotary screw (35).

5. The low-NOx combustion device for a heating furnace with self-adjusting flue gas circulation volume according to claim 1, characterized in that, The air inlet of the air inlet box (12) is rotatably connected to the air damper (121) via a rotating shaft (120). The outer wall of the air inlet box (12) is provided with a rotating arm (122) connected to the rotating shaft (120) and a second electric rod (123) connected to the rotating arm (122).

6. The low-NOx combustion device for a heating furnace with self-adjusting flue gas circulation volume according to claim 1, characterized in that, The end of the threaded rod (23) is provided with a positioning head (234) that is slidably engaged with the adjusting box (21).

7. The low-NOx combustion device for a heating furnace with self-adjusting flue gas circulation volume according to claim 1, characterized in that, The combustion chamber (11) is provided with a flame distribution plate (4), and several flame distribution holes (40) are evenly distributed on the flame distribution plate (4). The flame distribution holes (40) are frustum structures with larger upper parts and smaller lower parts.

8. The low-NOx combustion device for a heating furnace with self-adjusting flue gas circulation volume according to claim 7, characterized in that, A flow divider (41) is provided on the upper end face of the flame divider plate (4) and at the position corresponding to each flame divider hole (40).

9. A method for self-regulating flue gas recirculation using the low-NOx combustion equipment according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Connect the centrifugal fan (13), regulating motor (22) and return air fan (25) to the external power supply equipment respectively; S2. Fuel is introduced into the combustion chamber (11) through the fuel pipe (110), and the centrifugal fan (13) is started by the PLC controller. Under the action of the centrifugal fan (13), air enters the combustion chamber (11) through the air intake pipe (111) and mixes with the fuel for combustion. The flue gas generated during the combustion process is discharged through the exhaust pipe (112). S3. The PLC controller controls the start of the regulating motor (22) and the return air fan (25). The regulating motor (22) drives the regulating gear (220) to rotate, thereby driving the threaded sleeve (230) to rotate through the first gear ring (231). At this time, the threaded rod (23) pulls the sliding valve plate (24) inside the exhaust pipe (112) to move under the action of the threaded sleeve (230), so that the second exhaust groove (240) inside the exhaust pipe (112) and the first exhaust groove (25) are connected. 60) The exhaust pipe (112) outlet is sealed by overlapping; while the rotating sleeve (232) drives the second gear ring (233) during rotation, and the sliding valve plate (24) inside the circulation pipe (20) moves by the meshing action of the second gear ring (233) and the rack (241); the second exhaust groove (240) inside the circulation pipe (20) is connected to the first exhaust groove (260), and the flue gas enters the air inlet box (12) through the circulation pipe (20) for secondary combustion; S4. The oxygen concentration inside the combustion chamber (11) is monitored in real time using an oxygen sensor. When the oxygen concentration inside the combustion chamber (11) is lower than the set value, the regulating motor (22) is reversed by the PLC controller. This causes the second exhaust groove (240) inside the exhaust pipe (112) to gradually connect with the first exhaust groove (260), while the second exhaust groove (240) inside the circulation pipe (20) gradually overlaps with the first exhaust groove (260), thereby reducing the amount of flue gas circulating. S5. Repeat steps S3 and S4 to achieve dynamic adjustment of flue gas recirculation volume.

Images