A low-oxygen, low-nitrogen, energy-saving combustor assembly and method of use

Abstract

The application discloses a low-oxygen and low-nitrogen energy-saving combustor assembly and a use method thereof. The combustor assembly comprises a first combustor arranged on one side of a kiln body, a second combustor arranged on the other side of the kiln body, and a circulating pipeline. The use method of the combustor assembly comprises the following steps: S1, primary heating; S2, heating conversion; S3, secondary heating; and S4, circulation. The application adopts an ultra-low-nitrogen combustion technology, and combines a multiple coupling technology of a 'deviation equivalent ratio combustion technology + flue gas recirculation combustion technology + flameless combustion technology' to control the nitrogen oxide emission of a forging heating furnace to be less than or equal to 150 mg / m 3 (8% of the reference oxygen content) so that the equipment has the advantages of advanced technology, energy saving and environmental protection, and leads the future development direction of the combustion technology in the hot blast furnace and rotary kiln fields.

Description

Technical Field

[0001] This invention relates to the field of furnace burner technology, specifically to a low-NOx energy-saving burner assembly and its method of use for low-oxygen homogenization combustion. Background Technology

[0002] Boilers and industrial furnaces are the two largest stationary sources of nitrogen oxide emissions. Traditional regenerative burners and regenerative combustion systems only have energy-saving functions. Due to the high air temperature, the combustion temperature is also high. Taking natural gas as fuel as an example, the nitrogen oxide content in the flue gas emissions is more than 300 mg / m³, which is far higher than the industry and local air emission standards. The future development direction of industrial furnaces is to adopt burner products and systems that take into account both energy saving and environmental protection.

[0003] The survey shows that there are approximately 120,000 registered industrial furnaces, and a large number of industrial furnaces are not included in the statistics. The market stock, the size of each unit, and the amount of nitrogen oxide emissions are far greater than those of boilers, making them the largest stationary source of nitrogen oxide emissions. However, the control of nitrogen oxide emissions from industrial furnaces lacks standard support in terms of environmental management. There are many types of industrial furnaces, and the survey shows that many types of furnaces lack emission standards. The standards were introduced a long time ago and have hardly been updated in the past three years. The emission limits of most furnaces, such as heating furnaces and heat treatment furnaces, which have a large stock, are still relatively high, leaving a lot of room for reduction.

[0004] In terms of technology, nitrogen reduction technology for 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-saving benefits, and easy management to provide technical support for nitrogen oxide emission reduction in industrial furnaces. In terms of market application, most of the equipment used is single-function energy-saving or low-nitrogen equipment, while industrial combustion technologies and equipment that combine energy saving and environmental protection are still lacking. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a low-NOx energy-saving burner assembly with low-oxygen homogeneous combustion and its usage method.

[0006] The technical solution of this invention is:

[0007] A low-oxygen homogeneous combustion low-NOx energy-saving burner assembly includes a first burner disposed on one side of the kiln body, a second burner disposed on the other side of the kiln body, and a circulation pipeline, wherein the first burner and the second burner are mirror images of each other.

[0008] The first burner and the second burner include an L-shaped heat storage chamber. The top of the heat storage chamber is provided with an air inlet, and the bottom end of the heat storage chamber is provided with a flow distribution plate. The upper part of the heat storage chamber is provided with a ceramic honeycomb body connected to the air inlet. The bottom of the ceramic honeycomb body is provided with a hollow baffle for supporting the ceramic honeycomb body. A pre-combustion chamber is provided on the inner wall of the heat storage chamber directly below the ceramic honeycomb body. The upper part of the pre-combustion chamber is provided with an ignition gun that penetrates the heat storage chamber. The middle part of the pre-combustion chamber is provided with a gas spray gun that penetrates the heat storage chamber. The rear end of the gas spray gun opens downwards, and the front end of the gas spray gun penetrates the center of the heat storage chamber and the center of the pre-combustion chamber in sequence and then connects to the center of the flow distribution plate.

[0009] The circulation pipeline includes a first air guide pipe connected to the air inlet of the first burner, a second air guide pipe connected to the air inlet of the second burner, the first air guide pipe and the second air guide pipe being interconnected by a reversing valve, a third air guide pipe being provided on one side of the reversing valve, a blower being connected to the end of the third air guide pipe, and a fourth air guide pipe being provided on the other side of the reversing valve, the fourth air guide pipe including a first branch pipe and a second branch pipe, the first branch pipe being connected to the blower, and an induced draft fan being connected to the end of the second branch pipe.

[0010] Furthermore, the pre-combustion chamber is cylindrical, with a narrowed section on one side of the pre-combustion chamber along the airflow direction. Several air inlet slots are provided on the circumferential side wall of the pre-combustion chamber. An auxiliary spray gun is provided at the bottom of the gas spray gun located outside the heat storage chamber. The end of the auxiliary spray gun extends through the heat storage chamber and into the pre-combustion chamber.

[0011] Note: The air intake slot allows the pre-combustion chamber to better preheat the gas.

[0012] Furthermore, the front end of the gas spray gun is provided with a reduced diameter section, and a central gas nozzle is provided at the end of the reduced diameter section. A secondary gas nozzle is provided on the outer periphery of the reduced diameter section of the gas spray gun located behind the central gas nozzle. An auxiliary gas nozzle is also provided on the outer periphery of the middle part of the gas spray gun. A main flow channel for accommodating the reduced diameter section of the gas spray gun is provided in the middle of the flow distribution plate. Lateral flow channels are provided on the flow distribution plate in the direction corresponding to each of the auxiliary gas nozzles. The ends of the lateral flow channels and the main flow channels are connected through the auxiliary flow channels.

[0013] Note: Multi-stage gas nozzles can make the flow of gas or air smoother.

[0014] Furthermore, the outer periphery of the end of the heat storage chamber is provided with burner bricks for connection with the kiln body.

[0015] Furthermore, the induced draft fan is externally connected to a chimney.

[0016] Further, the reversing valve includes a valve body with four circumferential air inlets at the bottom. The first and second air inlets are connected to the left and right air inlets respectively, and the third and fourth air inlets are connected to the front and rear air inlets respectively. A rotating shaft is located at the center of the valve body. Two sealing plates are symmetrically arranged on the two side walls of the rotating shaft. Two cleaning plates are symmetrically arranged on the side walls of the rotating shaft perpendicular to the two sealing plates. The top of the rotating shaft passes through a top plate located at the center of the top of the valve body and connects to the output end of a drive motor located on the top plate. A cleaning brush is provided at the end of each cleaning plate, contacting the inner wall of the valve body. The cleaning plate inside the cleaning brush has a groove on its side wall. A slider is slidably connected to the upper part of the groove. The bottom of the slider is connected to the bottom of the groove by a spring. A filter screen for air passage is provided on the side wall of the cleaning plate inside the groove. An auxiliary brush for cleaning the filter screen is provided on the top of the slider on the side corresponding to the filter screen. An L-shaped rod is detachably connected to the top of the slider. A wave baffle is provided on the top of the valve body to support the L-shaped rod and allow the slider to slide up and down along the groove. An annular snap-fit ​​plate is detachably connected to the outer edge of the top plate. When the snap-fit ​​plate is placed, the wave baffle is sealed to the snap-fit ​​plate and the top plate.

[0017] Explanation: By optimizing and adjusting the internal structure of the reversing valve, it can filter and remove impurities from the high content of particles in the recovered air, preventing the valve body from becoming unsealed due to excessive particles. Furthermore, the slider and auxiliary brush are used to clean the filter screen, which is mainly used for air passage, improving the filter screen's permeability. Due to the setting of the slider and wave baffle, this cleaning process is carried out synchronously with the reversing valve switching, greatly improving work efficiency and saving the time of separate cleaning steps.

[0018] Furthermore, the top plate is fixedly connected to the side wall of the valve body by two symmetrically arranged fixing rods, the snap-fit ​​plate is composed of two semi-circular rings spliced ​​together, the bottom of the L-shaped rod is threadedly connected to the threaded groove provided on the top of the slider, and the slider is symmetrically provided with limiting blocks on both sides, and the limiting blocks are slidably connected with the limiting grooves provided on both sides of the inner wall of the slide groove.

[0019] Note: The detachable snap-fit ​​plate facilitates the installation and rotation of the L-shaped rod.

[0020] The method of using a low-oxygen homogeneous combustion, low-NOx energy-saving burner assembly according to any one of the above includes the following steps:

[0021] S1. Primary heating: Controlling the direction of the reversing valve connects the third air pipe with the first air pipe and the reversing valve. Turning on the blower allows ambient air to pass through the third air pipe, the reversing valve, and the first air pipe sequentially into the air inlet of the first burner. When the ambient air enters the ceramic honeycomb inside the heat storage chamber, the heat in the ceramic honeycomb heats the ambient air to 1000℃±20℃. The heated ambient air then enters the lower part of the heat storage chamber. At the same time, gas is introduced through the gas torch and ignited by the ignition gun. The main flame enters the kiln body through the flow distribution plate to generate high-temperature flue gas. The high-temperature flue gas enters the heat storage chamber from the front flow distribution plate of the second burner. After absorbing heat through the ceramic honeycomb, the high-temperature flue gas is cooled to below 150℃. The cooled high-temperature flue gas passes through the second air pipe, the reversing valve, and the fourth air pipe sequentially into the induced draft fan and is discharged into the chimney.

[0022] S2, Heating Conversion: When the high-temperature flue gas from the ceramic honeycomb body of the second burner absorbs heat and the temperature is still higher than 150℃ after cooling, the first burner stops working and controls the reversing valve to connect the third gas pipe with the second gas pipe and the reversing valve.

[0023] S3. Secondary heating: The blower is turned on, allowing room temperature air to enter the air inlet of the second burner through the third air guide pipe, the reversing valve, and the second air guide pipe. When the room temperature air enters the ceramic honeycomb inside the heat storage chamber, the heat in the ceramic honeycomb heats the room temperature air to 1000℃±20℃. Then, the heated room temperature air enters the lower part of the heat storage chamber. At the same time, gas is introduced through the gas spray gun and ignited by the ignition gun. The main flame enters the kiln body through the guide distribution plate to generate high-temperature flue gas. The high-temperature flue gas enters the heat storage chamber from the end guide distribution plate of the first burner. After absorbing heat through the ceramic honeycomb, the high-temperature flue gas is cooled to below 150℃. The cooled high-temperature flue gas enters the induced draft fan and is discharged into the chimney through the first air guide pipe, the reversing valve, and the fourth air guide pipe.

[0024] S4. Cycle: When the temperature of the high-temperature flue gas after absorbing heat by the ceramic honeycomb body of the first burner is still higher than 150°C after cooling down, the first burner stops working and repeats the process of steps S1 to S3.

[0025] Furthermore, the temperature of the high-temperature flue gas is 900~1300℃.

[0026] The beneficial effects of this invention are:

[0027] (1) The low-oxygen homogeneous combustion low-NOx energy-saving burner assembly of the present invention adopts ultra-low NOx combustion technology and integrates multiple coupling technologies such as "off-equivalence ratio combustion technology + flue gas recirculation combustion technology + flameless combustion technology" to control the NOx emissions of forging heating furnace to 150 mg / m³. 3 With an oxygen content of 8% or less, this equipment combines energy saving and environmental protection, making it technologically advanced and leading the future development of combustion technology in the industrial furnace field.

[0028] (2) The low-oxygen homogeneous combustion low-NOx energy-saving burner assembly of the present invention is an industrial energy-saving and environmental protection equipment for hot blast stoves and rotary kilns. In terms of energy-saving function, it adopts low-oxygen homogeneous combustion technology to achieve uniform flame under low oxygen conditions and has super combustion stability. Through reasonable design, it ensures that the fuel is completely and fully burned at different positions in the longitudinal direction of the furnace and kiln, which provides a guarantee for excellent energy-saving performance. The flame distribution is conducive to increasing the output of hot blast stoves and rotary kilns, further improving production efficiency, and bringing rich benefits and returns to enterprises.

[0029] (3) The low-oxygen homogeneous combustion low-NOx energy-saving burner assembly of the present invention optimizes and adjusts the internal structure of the reversing valve so that it can filter and remove impurities in the recovered air to prevent the valve body from being sealed poorly due to excessive impurities. The slider and auxiliary brush are used to clean the filter screen mainly used for air passage, which improves the permeability of the filter screen. Due to the setting of the slider and the wave baffle, this cleaning process is carried out synchronously with the switching of the reversing valve, which greatly improves the working efficiency and saves the time of separate cleaning steps. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of a low-NOx energy-saving burner assembly with low-oxygen homogeneous combustion according to the present invention.

[0031] Figure 2 This is a schematic diagram of the circulation pipeline structure in a low-NOx energy-saving burner assembly with low-oxygen homogeneous combustion according to the present invention.

[0032] Figure 3 This is a schematic diagram of the structure of the first burner in a low-NOx energy-saving burner assembly with low-oxygen homogeneous combustion according to the present invention.

[0033] Figure 4 This is a schematic diagram of the end structure of the heat storage chamber of the first burner in a low-NOx energy-saving burner assembly with low-oxygen homogeneous combustion according to the present invention.

[0034] Figure 5 This is a schematic diagram of the pre-combustion chamber structure in a low-oxygen homogeneous combustion, energy-saving burner assembly according to the present invention.

[0035] Figure 6 This is a schematic diagram of the airflow direction structure in a low-NOx energy-saving burner assembly with low-oxygen homogeneous combustion according to the present invention.

[0036] Figure 7 This is a schematic diagram of the gas flow path structure in a low-NOx energy-saving burner assembly with low-oxygen homogeneous combustion according to the present invention.

[0037] Figure 8 This is a schematic diagram of the reversing valve structure in a low-NOx energy-saving burner assembly with low-oxygen homogeneous combustion according to the present invention.

[0038] Figure 9 This is a schematic diagram of the internal structure of the reversing valve in a low-NOx energy-saving burner assembly with low-oxygen homogeneous combustion according to the present invention.

[0039] Figure 10 This is a schematic diagram of the connection between the slider and the groove of the reversing valve in a low-oxygen homogeneous combustion low-NOx energy-saving burner assembly of the present invention.

[0040] Among them, 1-first burner, 2-second burner, 3-circulation pipeline, 31-first air guide pipe, 32-second air guide pipe, 33-third air guide pipe, 331-blower, 34-fourth air guide pipe, 341-first branch pipe, 342-second branch pipe, 343-induced draft fan, 4-regenerator, 41-air inlet, 42-ceramic honeycomb body, 43-hollow baffle, 44-burner brick, 5-flow distribution plate, 51-main flow channel, 52-lateral flow channel, 53-auxiliary flow channel, 6-pre-combustion chamber, 61-ignition gun, 62-air inlet slot, 7-gas spray gun 71-Auxiliary spray gun, 72-Central gas nozzle, 73-Secondary gas nozzle, 74-Auxiliary gas nozzle, 8-Reversing valve, 81-Valve body, 811-Gas inlet, 812-Rotating shaft, 813-Sealing plate, 814-Top plate, 815-Drive motor, 816-Snap-fit ​​plate, 82-Cleaning plate, 821-Cleaning brush, 822-Slide groove, 823-Filter screen, 824-Limiting groove, 83-Slider, 831-Spring, 832-Auxiliary brush, 833-Threaded groove, 834-Limiting block, 84-L-shaped rod, 85-Wave baffle, 86-Fixing rod. Detailed Implementation

[0041] Example 1

[0042] like Figure 1 As shown, a low-oxygen homogeneous combustion low-NOx energy-saving burner assembly includes a first burner 1 disposed on one side of the kiln body, a second burner 2 disposed on the other side of the kiln body, and a circulation pipeline 3. The first burner 1 and the second burner 2 are arranged in a mirror image symmetrically.

[0043] like Figures 3-7As shown, the first burner 1 and the second burner 2 include an L-shaped heat storage chamber 4. An air inlet 41 is located at the top of the heat storage chamber 4, and a flow distribution plate 5 is located at the bottom end of the heat storage chamber 4. A ceramic honeycomb body 42 connected to the air inlet 41 is located in the upper part of the heat storage chamber 4. A hollow baffle 43 for supporting the ceramic honeycomb body 42 is located at the bottom of the ceramic honeycomb body 42. A pre-combustion chamber 6 is located on the inner wall of the heat storage chamber 4 directly below the ceramic honeycomb body 42. An ignition gun 61 penetrating the heat storage chamber 4 is located at the upper end of the pre-combustion chamber 6, and a gas flow path penetrating the heat storage chamber 4 is located in the middle of the pre-combustion chamber 6. The gas spray gun 7 has a downward-facing rear end opening. The front end of the gas spray gun 7 passes through the center of the heat storage chamber 4 and the pre-combustion chamber 6 in sequence and then connects to the center of the flow distribution plate 5. The pre-combustion chamber 6 is cylindrical. The middle part of the pre-combustion chamber 6 is a narrowing section along the air flow direction. The side wall of the pre-combustion chamber 6 is provided with 4 air inlet slots 62. The bottom of the gas spray gun 7 located outside the heat storage chamber 4 is provided with an auxiliary spray gun 71. The end of the auxiliary spray gun 71 passes through the heat storage chamber 4 and extends into the interior of the pre-combustion chamber 6. The outer periphery of the end of the heat storage chamber 4 is provided with burner bricks 44 for connecting with the kiln body.

[0044] like Figure 4 As shown, the front end of the gas spray gun 7 is a reduced diameter section. At the end of the reduced diameter section of the gas spray gun 7, there is a central gas nozzle 72. A secondary gas nozzle 73 is located on the outer periphery of the reduced diameter section of the gas spray gun 7 behind the central gas nozzle 72. An auxiliary gas nozzle 74 is also provided on the outer periphery of the middle part of the gas spray gun 7. The middle part of the flow distribution plate 5 is provided with a main flow channel 51 for accommodating the reduced diameter section of the gas spray gun 7. A lateral flow channel 52 is provided on the flow distribution plate 5 in the direction corresponding to each auxiliary gas nozzle 74. The ends of the lateral flow channel 52 and the main flow channel 51 are connected through the auxiliary flow channel 53.

[0045] like Figure 2 As shown, the circulation pipeline 3 includes a first air guide pipe 31 connected to the air inlet 41 of the first burner 1, and a second air guide pipe 32 connected to the air inlet 41 of the second burner 2. The first air guide pipe 31 and the second air guide pipe 32 are connected to each other through a reversing valve 8. A third air guide pipe 33 is provided on one side of the reversing valve 8. A blower 331 is connected to the end of the third air guide pipe 33. A fourth air guide pipe 34 is provided on the other side of the reversing valve 8. The fourth air guide pipe 34 includes a first branch pipe 341 and a second branch pipe 342. The first branch pipe 341 is connected to the blower 331. An induced draft fan 343 is connected to the end of the second branch pipe 342. The induced draft fan 343 is externally connected to the chimney. Both the blower 331 and the induced draft fan 343 are commercially available products.

[0046] like Figures 8-10As shown, the reversing valve 8 includes a valve body 81. Four air inlets 811 are circumferentially arranged at the bottom of the valve body 81. A first air inlet pipe 31 and a second air inlet pipe 32 are connected to the left and right air inlets 811 respectively. A third air inlet pipe 33 and a fourth air inlet pipe 34 are connected to the front and rear air inlets 811 respectively. A rotating shaft 812 is located at the center of the valve body 81. Two sealing plates 813 are symmetrically arranged on the two side walls of the rotating shaft 812. Two cleaning plates 82 are symmetrically arranged on the side walls of the rotating shaft 812 perpendicular to the two sealing plates 813. The top of the rotating shaft 812 passes through a top plate 814 located at the center of the top of the valve body 81 and is connected to the output end of a drive motor 815 located on the top plate 814. The drive motor 815 is a commercially available gear reduction motor. A cleaning brush 821 is located at the end of the cleaning plate 82, contacting the inner wall of the valve body 81. The cleaning plate 82 inside the brush 821 has a groove 822 on its side wall. The upper part of the groove 822 has a slider 83 that is slidably connected to it. The bottom of the slider 83 is connected to the bottom of the groove 822 by a spring 831. The cleaning plate 82 inside the groove 822 has a filter screen 823 for air passage. The top of the slider 83 and the side corresponding to the filter screen 823 have an auxiliary brush 832 for cleaning the filter screen 823. The top of the slider 83 is detachably connected to an L-shaped rod 84. The top of the valve body 81 has a wave baffle 85 for supporting the L-shaped rod 84 and allowing the slider 83 to slide up and down along the groove 822. The outer edge of the top plate 814 is detachably connected to an annular snap-fit ​​plate 816. When the snap-fit ​​plate 816 is placed, the wave baffle 85 is sealed to the snap-fit ​​plate 816 and the top plate 814.

[0047] like Figures 8-10 As shown, the top plate 814 is fixedly connected to the side wall of the valve body 81 by two symmetrically arranged fixing rods 86. The snap-fit ​​plate 816 is composed of two semi-circular rings spliced ​​together. The bottom of the L-shaped rod 84 is threadedly connected to the threaded groove 833 provided on the top of the slider 83. The slider 83 is symmetrically provided with limiting blocks 834 on both sides. The limiting blocks 834 are slidably connected to the limiting grooves 824 provided on both sides of the inner wall of the slide groove 822.

[0048] Example 2

[0049] The difference between this embodiment and Embodiment 1 is that:

[0050] The pre-combustion chamber has six air inlet slots 62 on its circumferential side walls.

[0051] Example 3

[0052] This embodiment describes a method for using a low-oxygen homogeneous combustion, low-NOx energy-saving burner assembly as described in Embodiment 1, including the following steps:

[0053] S1. Primary Heating: Controlling the direction of the reversing valve 8 connects the third air pipe 33 with the first air pipe 31 and the reversing valve 8. The blower 331 is turned on, allowing ambient air at 25°C to sequentially pass through the third air pipe 33, the reversing valve 8, and the first air pipe 31 into the air inlet 41 of the first burner 1. When the ambient air enters the ceramic honeycomb structure 42 inside the heat storage chamber 4, the heat within the ceramic honeycomb structure 42 heats the ambient air to 1000°C. The heated ambient air then enters the heat storage chamber 4. In the lower part of the hot chamber 4, gas is introduced through the gas spray gun 7 and ignited by the ignition gun 61. The main flame enters the kiln body through the guide distribution plate 5 to generate high-temperature flue gas. The high-temperature flue gas enters the heat storage chamber 4 from the front guide distribution plate 5 of the second burner 2. After the ceramic honeycomb body 42 absorbs heat, the high-temperature flue gas is cooled to below 150°C. The cooled high-temperature flue gas enters the induced draft fan 343 and is discharged into the chimney through the second gas guide pipe 32, the reversing valve 8 and the fourth gas guide pipe 34.

[0054] S2, Heating Conversion: When the temperature of the high-temperature flue gas after absorbing heat by the ceramic honeycomb body 42 of the second burner 2 is still higher than 150°C after cooling down, the first burner 1 stops working and controls the direction of the reversing valve 8 to make the third air pipe 33 connected to the second air pipe 32 and the reversing valve 8.

[0055] S3. Secondary heating: The blower 331 is turned on, so that the ambient temperature air passes through the third air guide pipe 33, the reversing valve 8 and the second air guide pipe 32 in sequence and enters the air inlet 41 of the second burner 2. When the ambient temperature air enters the ceramic honeycomb body 42 inside the heat storage chamber 4, the heat in the ceramic honeycomb body 42 heats the ambient temperature air to 1000℃. Then the heated ambient temperature air enters the lower part of the heat storage chamber 4. At the same time, gas is introduced through the gas spray gun 7 and the main flame is ignited by the ignition gun 61. The main flame enters the furnace body through the guide distribution plate 5 to generate high temperature flue gas. The high temperature flue gas enters the heat storage chamber 4 from the end guide distribution plate 5 of the first burner 1. After absorbing heat through the ceramic honeycomb body 42, the high temperature flue gas is cooled to below 150℃. The cooled high temperature flue gas passes through the first air guide pipe 31, the reversing valve 8 and the fourth air guide pipe 34 in sequence and enters the induced draft fan 343 and is discharged into the chimney.

[0056] S4. Cycle: When the temperature of the high-temperature flue gas after absorbing heat by the ceramic honeycomb body 42 of the first burner 1 is still higher than 150°C after cooling down, the first burner 1 stops working and repeats the process of steps S1 to S3. During the above process, the temperature of the high-temperature flue gas is controlled at around 1000°C.

[0057] Example 4

[0058] The difference between this embodiment and embodiment 3 is that:

[0059] S1. During the initial heating process, the heat from the ceramic honeycomb 42 heats the room temperature air to 980℃.

[0060] S3. During the secondary heating process, the heat in the ceramic honeycomb 42 heats the room temperature air to 980℃.

[0061] During the above process, the temperature of the high-temperature flue gas is controlled at around 900℃.

[0062] Example 5

[0063] The difference between this embodiment and embodiment 3 is that:

[0064] S1. During the initial heating process, the heat from the ceramic honeycomb 42 heats the room temperature air to 1200℃.

[0065] S3. During the secondary heating process, the heat in the ceramic honeycomb 42 heats the room temperature air to 1200℃.

[0066] During the above process, the temperature of the high-temperature flue gas was controlled at around 1300℃.

[0067] Working principle:

[0068] The working principle of the reversing valve 8 in a low-oxygen homogeneous combustion low-NOx energy-saving burner assembly of the present invention will be briefly explained below.

[0069] When performing step S1, firstly, the reversing valve 8... Figure 8In the state shown, the drive motor 815 is turned on to drive the rotating shaft 812 to rotate, rotating one of the sealing plates 813 to the position between the two air inlets 811 corresponding to the third air inlet 33 and the second air inlet 32. This allows the cooled high-temperature flue gas to pass sequentially through the second air inlet 32, the reversing valve 8, and the fourth air inlet 34 into the induced draft fan 343 and then into the chimney. When passing through the reversing valve 8, the flue gas flows through the filter screen 823 on one of the cleaning plates 82, which filters out impurities. When step S1 is completed and step S2 is performed, the filter screen 823 needs to be cleaned. At this time, the two snap-fit ​​plates 816 are removed, and the L-shaped rod 84 is installed. The bottom of the L-shaped rod 84 is aligned with the threaded groove. 833 is fixed by rotating the thread, and then the drive motor 815 is turned on to drive the rotating shaft 812 to rotate 6 to 8 times. At the same time, the L-shaped rod 84 moves up and down under the action of the wave baffle 85, and at the same time drives the slider 83 to slide up and down. Under the action of the spring 831, the slider 83 can be reset when the L-shaped rod 84 moves to the lowest point of the wave baffle 85. At the same time, the auxiliary brush 832 also moves up and down, and its position corresponds to the position of the filter screen 823, so that the filter screen 823 can be cleaned. At the same time, the cleaning brush 821 cleans the inner wall of the valve body 81 to ensure the sealing of the reversing valve 8. After cleaning, the impurities at the bottom of the valve body 81 are sucked out, and the process of step S3 can be started.

[0070] Experimental Example

[0071] A vanadium-titanium company used the burner assembly of this invention on four rotary kilns. After replacing the burner assembly with the one of this invention, the flue gas emission values ​​of the rotary kilns were: NOx ≤ 100 mg / m³. 3 (@9%O2), CO≤60mg / m³ 3 (@9% O2), nitrogen oxide emissions are reduced by more than 50%. In addition to meeting environmental standards, the material roasting quality is high, the yield and processing speed are greatly improved, and the overall energy consumption is reduced by more than 10%.

[0072] A lithium company used the burner assembly of this invention in a hot blast stove of an acidification kiln. After replacing the burner assembly with the one of this invention, the flue gas emission value of the hot blast stove was: NOx ≤ 100 mg / m³. 3 (@8%O2), CO≤60mg / m³ 3 (@8%O2), nitrogen oxide emissions are reduced by more than 80%.

[0073] The burner assembly of this invention was used in four forging heating furnaces and heat treatment furnaces at the forging plant of a heavy equipment company. All four furnaces were converted to regenerative combustion mode. After replacing the burner assembly with the one of this invention, the flue gas emission values ​​of the forging heating furnaces and heat treatment furnaces were: NOx ≤ 150 mg / m³. 3 (@8%O2), CO≤60mg / m³3 (@8% O2), nitrogen oxide emissions are reduced by more than 100%. In addition to meeting environmental standards, natural gas consumption is reduced by more than 30% compared to conventional combustion methods.

Claims

1. A low-NOx energy-saving burner assembly with low-oxygen homogeneous combustion, characterized in that, It includes a first burner (1) set on one side of the kiln body, a second burner (2) set on the other side of the kiln body, and a circulation pipeline (3). The first burner (1) and the second burner (2) are mirror images of each other. The first burner (1) and the second burner (2) include an L-shaped heat storage chamber (4). The top of the heat storage chamber (4) is provided with an air inlet (41), and the bottom end of the heat storage chamber (4) is provided with a flow distribution plate (5). The upper part of the heat storage chamber (4) is provided with a ceramic honeycomb body (42) connected to the air inlet (41). The bottom of the ceramic honeycomb body (42) is provided with a hollow baffle (43) for supporting the ceramic honeycomb body (42). The inner wall of the heat storage chamber (4) located directly below the ceramic honeycomb body (42) is provided with a pre-combustion chamber (6). The upper part of the pre-combustion chamber (6) is provided with an ignition gun (61) penetrating the heat storage chamber (4). The middle part of the pre-combustion chamber (6) is provided with a gas spray gun (7) penetrating the heat storage chamber (4). The rear end of the gas spray gun (7) opens downward. The front end of the gas spray gun (7) passes through the center of the heat storage chamber (4) and the center of the pre-combustion chamber (6) in sequence and then connects to the center of the flow distribution plate (5). The circulation pipeline (3) includes a first air guide pipe (31) connected to the air inlet (41) of the first burner (1) and a second air guide pipe (32) connected to the air inlet (41) of the second burner (2). The first air guide pipe (31) and the second air guide pipe (32) are connected to each other through a reversing valve (8). A third air guide pipe (33) is provided on one side of the reversing valve (8). A blower (331) is connected to the end of the third air guide pipe (33). A fourth air guide pipe (34) is provided on the other side of the reversing valve (8). The fourth air guide pipe (34) includes a first branch pipe (341) and a second branch pipe (342). The first branch pipe (341) is connected to the blower (331), and the end of the second branch pipe (342) is connected to an induced draft fan (343). The reversing valve (8) includes a valve body (81). The bottom of the valve body (81) is provided with four air inlets (811) circumferentially. The first air inlet pipe (31) and the second air inlet pipe (32) are respectively connected to the left and right air inlets (811). The third air inlet pipe (33) and the fourth air inlet pipe (34) are respectively connected to the front and rear air inlets (811). A rotating shaft (812) is provided at the center of the valve body (81). The rotating shaft (812) has symmetrically arranged side walls. Two sealing plates (813) are provided. Two cleaning plates (82) are symmetrically provided on the side wall of the rotating shaft (812) perpendicular to the two sealing plates (813). The top of the rotating shaft (812) passes through the top plate (814) provided at the center of the top of the valve body (81) and is connected to the output end of the drive motor (815) located on the top plate (814). The cleaning plate (82) is provided with a cleaning brush (821) at the end that contacts the inner wall of the valve body (81). The cleaning brush (821) is located inside the cleaning brush (821). A sliding groove (822) is provided on the side wall of the cleaning plate (82). A slider (83) is provided in the upper part of the sliding groove (822) and is slidably connected to it. The bottom of the slider (83) is connected to the bottom of the sliding groove (822) by a spring (831). A filter screen (823) for air passage is provided on the side wall of the cleaning plate (82) located inside the sliding groove (822). An auxiliary tool for cleaning the filter screen (823) is provided on the top of the slider (83) on the side corresponding to the filter screen (823). The top of the brush (832) and the slider (83) are detachably connected to an L-shaped rod (84). The top of the valve body (81) is provided with a wave baffle (85) for supporting the L-shaped rod (84) and allowing the slider (83) to slide up and down along the slide groove (822). The outer edge of the top plate (814) is detachably connected to an annular snap-fit ​​plate (816). When the snap-fit ​​plate (816) is placed, the wave baffle (85) is sealed to the snap-fit ​​plate (816) and the top plate (814).

2. The low-oxygen homogeneous combustion, low-NOx energy-saving burner assembly according to claim 1, characterized in that, The pre-combustion chamber (6) is cylindrical. The middle part of the pre-combustion chamber (6) is a narrow section along the air flow direction. The side wall of the pre-combustion chamber (6) is provided with several air inlet slots (62) in the circumferential direction. The bottom of the gas spray gun (7) located outside the heat storage chamber (4) is provided with an auxiliary spray gun (71). The end of the auxiliary spray gun (71) extends through the heat storage chamber (4) and into the interior of the pre-combustion chamber (6).

3. The low-oxygen homogeneous combustion, low-NOx energy-saving burner assembly according to claim 1, characterized in that, The front end of the gas spray gun (7) is provided with a reduced diameter section. At the end of the reduced diameter section of the gas spray gun (7) is a central gas nozzle (72). A secondary gas nozzle (73) is provided on the outer periphery of the reduced diameter section of the gas spray gun (7) located behind the central gas nozzle (72). An auxiliary gas nozzle (74) is also provided on the outer periphery of the middle part of the gas spray gun (7). The middle part of the flow distribution plate (5) is provided with a main flow channel (51) for accommodating the reduced diameter section of the gas spray gun (7). A lateral flow channel (52) is provided on the flow distribution plate (5) in the direction corresponding to each of the auxiliary gas nozzles (74). The ends of the lateral flow channel (52) and the main flow channel (51) are connected through the auxiliary flow channel (53).

4. The low-oxygen homogeneous combustion, low-NOx energy-saving burner assembly according to claim 1, characterized in that, The outer periphery of the end of the heat storage chamber (4) is provided with burner bricks (44) for connection with the kiln body.

5. The low-oxygen homogeneous combustion, low-NOx energy-saving burner assembly according to claim 1, characterized in that, The induced draft fan (343) is externally connected to the chimney.

6. The low-oxygen homogeneous combustion, low-NOx energy-saving burner assembly according to claim 1, characterized in that, The top plate (814) is fixedly connected to the side wall of the valve body (81) by two symmetrically arranged fixing rods (86). The snap-fit ​​plate (816) is composed of two semi-circular rings spliced ​​together. The bottom of the L-shaped rod (84) is threadedly connected to the threaded groove (833) provided on the top of the slider (83). The slider (83) is symmetrically provided with limiting blocks (834) on both sides. The limiting blocks (834) are slidably connected with the limiting grooves (824) provided on both sides of the inner wall of the slide groove (822).

7. A method of using a low-oxygen homogeneous combustion, low-NOx energy-saving burner assembly according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Primary heating: Controlling the direction of the reversing valve (8) connects the third air pipe (33) with the first air pipe (31) and the reversing valve (8). The blower (331) is turned on, allowing ambient air to pass through the third air pipe (33), the reversing valve (8), and the first air pipe (31) in sequence into the air inlet (41) of the first burner (1). When the ambient air enters the ceramic honeycomb body (42) inside the heat storage chamber (4), the heat in the ceramic honeycomb body (42) heats the ambient air to 1000℃±20℃. Then, the heated ambient air enters the heat storage chamber (4). In the lower part of the heat storage chamber (4), at the same time, gas is introduced through the gas spray gun (7) and the main flame is ignited by the ignition gun (61). The main flame enters the furnace body through the guide distribution plate (5) to generate high-temperature flue gas. The high-temperature flue gas enters the heat storage chamber (4) from the front guide distribution plate (5) of the second burner (2). After absorbing heat through the ceramic honeycomb body (42), the high-temperature flue gas is cooled to below 150°C. The cooled high-temperature flue gas passes through the second gas guide pipe (32), the reversing valve (8) and the fourth gas guide pipe (34) in sequence and enters the induced draft fan (343) and is discharged into the chimney. S2, heating conversion: When the temperature of the high-temperature flue gas after the ceramic honeycomb body (42) of the second burner (2) absorbs heat is still higher than 150°C after cooling down, the first burner (1) stops working and controls the direction of the reversing valve (8) to make the third gas pipe (33) connected to the second gas pipe (32) and the reversing valve (8). S3, Secondary Heating: Turn on the blower (331) to allow ambient air to pass through the third air guide pipe (33), the reversing valve (8), and the second air guide pipe (32) in sequence into the air inlet (41) of the second burner (2). When the ambient air enters the ceramic honeycomb body (42) inside the heat storage chamber (4), the heat in the ceramic honeycomb body (42) heats the ambient air to 1000℃±20℃. Then, the heated ambient air enters the lower part of the heat storage chamber (4). At the same time, it is heated by the gas spray gun (7). Gas is introduced and ignited by an igniter (61). The main flame is ignited and enters the furnace body through the guide distribution plate (5) to generate high-temperature flue gas. The high-temperature flue gas enters the heat storage chamber (4) from the end guide distribution plate (5) of the first burner (1). The high-temperature flue gas is cooled to below 150°C by absorbing heat through the ceramic honeycomb body (42). The cooled high-temperature flue gas enters the induced draft fan (343) and is discharged into the chimney through the first gas guide pipe (31), the reversing valve (8) and the fourth gas guide pipe (34). S4. Cycle: When the temperature of the high-temperature flue gas after the ceramic honeycomb body (42) of the first burner (1) absorbs heat is still higher than 150°C after cooling down, the second burner (2) stops working and repeats the process of steps S1 to S3.

8. The method of using a low-oxygen homogeneous combustion, low-NOx energy-saving burner assembly according to claim 7, characterized in that, The temperature of the high-temperature flue gas is 900~1300℃.

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