Low-emission gas-fired boiler combustion device and method thereof

Abstract

The invention discloses a low-emission gas-fired boiler combustion device and method, the low-emission gas-fired boiler combustion device comprises an air premixing assembly, a combustion assembly and a burnout assembly, the air premixing assembly communicates with the combustion assembly, and the combustion assembly communicates with the burnout assembly; the air premixing assembly comprises a mixing tank, a premixing chamber, an air inlet pipe, a fuel gas inlet pipe, a first air distribution plate, two limiting rings, a rotating shaft, mixing blades and a driving impeller; the air inlet pipe and the fuel gas inlet pipe are both installed on the lower surface of the premixing chamber. Fuel gas and air are premixed in the premixing chamber, then gas preliminarily mixed in the premixing chamber flows into the mixing tank to be secondarily mixed, the fuel gas can be evenly distributed in the main combustion chamber after being evenly mixed, and therefore the situation that the concentration of the fuel gas in a local area is too high or too low is avoided; the uniform fuel gas distribution enables the combustion process to be more uniform, and the condition that the temperature of part of flames is relatively high does not exist, so that the generation rate and the generation amount of nitrogen oxides are reduced.

Description

Technical Field

[0001] The present invention relates to a combustion device and a method thereof, specifically to a low-emission gas boiler combustion device and a method thereof, belonging to the technical field of gas boilers. Background Art

[0002] A gas boiler is a heat energy conversion device that heats water into hot water or steam by burning gas (such as natural gas, liquefied gas, etc.) for heating, bathing, or industrial use. Its core consists of a "boiler" (a water-containing container) and a "furnace" (a combustion chamber), supplemented by a control system, safety devices, etc. During operation, the gas boiler burns gas in the combustion chamber to generate high-temperature flue gas, and the heat exchanger transfers the heat to the water in the water circulation system to generate hot water or steam.

[0003] The gas boiler combustion device generates nitrogen oxides during operation, mainly including thermal nitrogen oxides, which are formed by the oxidation of N2 in the combustion air at high temperatures. The main factors affecting the formation of thermal nitrogen oxides are combustion temperature, oxygen concentration, and reaction time. The higher the temperature, the greater the amount of nitrogen oxides generated. When the temperature is lower than 1000K (about 700 degrees Celsius), the amount of nitrogen oxides generated is very small; but when the temperature reaches around 1500°C, for every 100°C increase in temperature, the reaction rate will increase by 6 - 7 times, and the amount of nitrogen oxides generated will increase rapidly; In order to reduce the emission of nitrogen oxides, the prior art often uses staged combustion technology and flue gas recirculation technology to process the combustion process. Among them, the staged combustion technology divides the combustion process into multiple stages, such as the main combustion zone, the reburn zone, and the burnout zone. In the main combustion zone, by reducing the air supply, the fuel burns in an oxygen-deficient or lean-oxygen state, reducing the combustion temperature. The flue gas recirculation technology reintroduces part of the combustion flue gas into the combustion zone, reducing the oxygen concentration and diluting the reactants in the combustion zone, thereby reducing the formation of nitrogen oxides; However, during the combustion process, the mixing condition of gas and air is often difficult to reach an ideal state. Due to uneven mixing, the gas is unevenly distributed in the combustion chamber, resulting in too high or too low gas concentration in local areas. This uneven gas distribution makes the combustion process uneven, with some areas burning too violently and some areas burning insufficiently. Therefore, this uneven combustion will lead to a relatively high flame temperature, and high temperature is one of the important conditions for the formation of thermal nitrogen oxides. When the temperature exceeds a certain threshold, nitrogen in the air will chemically react with oxygen to generate nitrogen oxides. Therefore, the increase in flame temperature will significantly increase the generation rate and amount of nitrogen oxides. For this reason, a low-emission gas boiler combustion device and a method thereof are proposed. Summary of the Invention

[0004] The object of the present invention is to provide a low-emission gas boiler combustion device and its method to solve one of the problems raised in the above-mentioned background technology.

[0005] The present invention is implemented by the following technical solutions: A low-emission gas boiler combustion device includes an air premixing component, a combustion component, and a burnout component. The air premixing component is communicated with the combustion component, and the combustion component is communicated with the burnout component. The air premixing component includes a mixing tank, a premixing chamber, an air inlet pipe, a gas inlet pipe, a first air distribution plate, two limiting rings, a rotating shaft, mixing blades, and a driving impeller. The air inlet pipe and the gas inlet pipe are both installed on the lower surface of the premixing chamber. Proportion valves are installed on the outer side walls of the air inlet pipe and the gas inlet pipe. The first air distribution plate is installed inside the premixing chamber. The mixing tank is installed on the upper surface of the premixing chamber and is communicated with the premixing chamber. The rotating shaft is rotatably connected inside the two limiting rings. The mixing blades are fixedly connected to the outer side wall of the rotating shaft, and the driving impeller is fixedly connected to the outer side wall of the rotating shaft.

[0006] As a further preference of this technical solution: The two limiting rings are symmetrically and fixedly connected to the inner side wall of the mixing tank, and a conveying pipe is installed on the upper surface of the mixing tank.

[0007] As a further preference of this technical solution: The combustion component includes a main combustion chamber, a shunt pipe, two return pipes, a combustion hood, a main burner, a baffle plate, a second air distribution plate, an exhaust hood, and two smoke exhaust holes. The baffle plates are fixedly connected to the inner front wall and the inner rear wall of the main combustion chamber, and the baffle plates are arranged in a staggered manner. The main burner is installed on one side of the main combustion chamber. The combustion hood is fixedly connected to one side of the inner wall of the main combustion chamber and corresponds to the position of the main burner. The second air distribution plate is fixedly connected to the inner side wall of the main combustion chamber and is located below the baffle plates. The exhaust hood is installed on the inner bottom wall of the main combustion chamber. The two smoke exhaust holes are symmetrically opened on the upper surface of the shunt pipe. The two return pipes are symmetrically located on both sides of the main combustion chamber.

[0008] As a further preference of this technical solution: The top end of the return pipe is communicated with the outer wall of the shunt pipe, and the bottom end of the return pipe is communicated with the outer wall of the exhaust hood.

[0009] As a further preference of this technical solution: The end of the conveying pipe away from the mixing tank is fixedly connected to the lower surface of the main combustion chamber and is communicated with the exhaust hood. The premixing chamber is installed on the rear surface of the main combustion chamber.

[0010] As a further preference of this technical solution: A temperature sensor is installed on one side of the main combustion chamber, and the probe of the temperature sensor is located inside the main combustion chamber.

[0011] As a further preference of this technical solution: The burnout assembly includes a secondary combustion chamber, a secondary burner, a third air distribution plate, a cover plate, and a smoke inlet pipe; The secondary burner is installed on one side of the secondary combustion chamber, the third air distribution plate is installed on the inner side wall of the secondary combustion chamber, the smoke inlet pipe is installed on the upper surface of the cover plate, and the secondary combustion chamber is installed on the rear surface of the main combustion chamber.

[0012] As a further preference of this technical solution: The cover plate is installed on the upper surface of the secondary combustion chamber, the end of the secondary burner is located below the third air distribution plate, and a smoke exhaust pipe is installed on one side of the secondary combustion chamber away from the secondary burner.

[0013] As a further preference of this technical solution: One end of the smoke inlet pipe away from the secondary combustion chamber is installed on the upper surface of the shunt pipe and is communicated with the shunt pipe.

[0014] A low-emission gas combustion method includes the following steps: Initial air mixing: Use a proportional valve to control the air volume and gas volume entering the premixing chamber. The air and gas are initially mixed in the premixing chamber and then flow into the mixing tank through the first air distribution plate for secondary mixing; Secondary air mixing: The preliminarily mixed gas pushes the drive impeller in the mixing tank. The drive impeller drives the mixing blades through a rotating shaft, and the mixing blades agitate the initially mixed gas to achieve secondary full mixing; Initial combustion: The mixed gas flows from the exhaust hood into the main combustion chamber, uniformly flows upward through the second air distribution plate, the main burner burns the gas, heats the heat exchange pipes in the main combustion chamber, and the generated flue gas flows into the shunt pipe; Flue gas circulating combustion: When the gas flows from the exhaust hood into the main combustion chamber, a negative pressure is generated at the bottom of the return pipe, and a part of the flue gas in the top shunt pipe flows into the return pipe and then flows into the main combustion chamber again through the return pipe to perform circulating combustion on the flue gas; Secondary flue gas combustion: The flue gas flows into the secondary combustion chamber through the smoke inlet pipe, the secondary burner burns the flue gas again, reduces the oxygen concentration, dilutes the reactants in the combustion zone, and the burned flue gas is discharged from the smoke exhaust pipe.

[0015] Advantages of the present invention: 1. In the present invention, gas and air are premixed in a premixing chamber, and the ratio of air and gas entering the premixing chamber is precisely controlled by a proportional valve. Then, the gas preliminarily mixed in the premixing chamber flows into a mixing tank for secondary mixing. At this time, the preliminarily mixed gas flows upward in the mixing tank, and the gas pushes a driving impeller during the flowing process. With the cooperation of structures such as a rotating shaft, a limiting ring, and mixing blades, the preliminarily mixed gas can be agitated to achieve secondary full mixing of air and gas. After uniform mixing, the gas can be evenly distributed in the main combustion chamber, and thus there will be no situation where the gas concentration in a local area is too high or too low. This uniform gas distribution can make the combustion process more uniform, and there will be no situation where the temperature of some flames is relatively high, so as to reduce the generation rate and amount of nitrogen oxides. 2. The gas after secondary mixing in the present invention flows into an exhaust hood through a delivery pipe and then into the main combustion chamber. At this time, the gas flows upward after passing through a second air distribution plate. The second air distribution plate can make the gas flow upward evenly, and then the gas is burned by a main burner. When the gas flows from the exhaust hood into the main combustion chamber, a negative pressure is generated at the bottom of the return pipe, thereby pushing the flue gas in the top shunt pipe. A part of the flue gas flows into the return pipe and then flows back into the main combustion chamber through the return pipe, thus realizing the circulating combustion of the flue gas. By reintroducing the flue gas into the combustion zone, the oxygen concentration can be reduced and the reactants in the combustion zone can be diluted, thereby reducing the generation of nitrogen oxides. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is a schematic structural diagram of a combustion device for a low-emission gas boiler according to the present invention; Figure 2 It is a schematic diagram of the installation position of the return pipe according to the present invention; Figure 3 It is a schematic structural diagram of an air premixing assembly according to the present invention; Figure 4 It is an exploded schematic structural diagram of the air premixing assembly according to the present invention; Figure 5 It is a schematic structural diagram of a driving impeller according to the present invention; Figure 6 It is a schematic structural diagram of a combustion assembly according to the present invention; Figure 7 It is a schematic structural diagram of a shunt pipe according to the present invention; Figure 8Schematic diagram of the structural decomposition of the burnout component of the present invention.

[0018] In the figure: 101, air premixing component; 11, mixing tank; 12, premixing chamber; 13, proportional valve; 14, air inlet pipe; 15, gas inlet pipe; 16, conveying pipe; 17, first air distribution plate; 18, limiting ring; 19, rotating shaft; 20, mixing blade; 21, driving impeller; 301, combustion component; 31, main combustion chamber; 32, shunt pipe; 33, return pipe; 34, combustion hood; 35, main burner; 36, guide plate; 37, second air distribution plate; 38, temperature sensor; 39, exhaust hood; 40, smoke exhaust hole; 401, burnout component; 41, secondary combustion chamber; 42, secondary burner; 43, third air distribution plate; 44, cover plate; 45, smoke inlet pipe; 46, smoke exhaust pipe. Specific embodiments

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] Embodiment Please refer to Figures 1-8 , the present invention provides a technical solution: a low-emission gas boiler combustion device, including an air premixing component 101, a combustion component 301, and a burnout component 401. The air premixing component 101 is connected to the combustion component 301, and the combustion component 301 is connected to the burnout component 401; The air premixing component 101 is used to realize the mixing of air and gas. After uniform mixing, the gas can be evenly distributed in the main combustion chamber 31, so that there will be no situation where the gas concentration is too high or too low in a local area. This uniform gas distribution can make the combustion process more uniform, and there will be no situation where the temperature of some flames is relatively high, so as to reduce the generation rate and generation amount of nitrogen oxides; The combustion component 301 is used to realize the combustion of gas. A part of the flue gas generated after the gas combustion can flow back into the interior of the main combustion chamber 31 again. By reintroducing the flue gas into the combustion zone, the oxygen concentration can be reduced, and the reactants in the combustion zone can be diluted, thereby reducing the generation of nitrogen oxides; The burnout component 401 is used to burn the discharged flue gas again, thereby reducing the oxygen concentration again and reducing the generation of nitrogen oxides; The air premixing component 101 includes a mixing tank 11, a premixing chamber 12, an air inlet pipe 14, a gas inlet pipe 15, a first air distribution plate 17, two limiting rings 18, a rotating shaft 19, mixing blades 20, and a driving impeller 21; The air inlet pipe 14 and the gas inlet pipe 15 are both installed on the lower surface of the premixing chamber 12. Proportioning valves 13 are installed on the outer side walls of the air inlet pipe 14 and the gas inlet pipe 15. The air inlet pipe 14 is connected to an external blower, and the gas inlet pipe 15 is connected to an external gas pipeline. The proportioning valve 13 can precisely control the proportion of air and gas entering the premixing chamber 12. By precisely controlling the mixing ratio of gas and air, it can ensure that the combustion process proceeds under the condition of the best air-fuel ratio, enabling the gas to burn fully, improving the combustion efficiency, reducing the generation of incomplete combustion products. At the same time, since the combustion is more uniform, the flame temperature is effectively controlled, avoiding the generation of high-temperature hot spots, thereby significantly reducing the generation rate and emission concentration of thermal type nitrogen oxides, and contributing to achieving a more environmentally friendly and efficient combustion process; The first air distribution plate 17 is installed inside the premixing chamber 12, and the preliminary mixing effect of air and gas can be enhanced through the first air distribution plate 17; The mixing tank 11 is installed on the upper surface of the premixing chamber 12 and is connected to the premixing chamber 12. The rotating shaft 19 is rotatably connected inside the two limiting rings 18. The mixing blades 20 are fixedly connected to the outer side wall of the rotating shaft 19, and the driving impeller 21 is fixedly connected to the outer side wall of the rotating shaft 19. The two limiting rings 18 are symmetrically and fixedly connected to the inner side wall of the mixing tank 11. A delivery pipe 16 is installed on the upper surface of the mixing tank 11. The gas preliminarily mixed in the premixing chamber 12 flows into the mixing tank 11 for secondary mixing. At this time, the preliminarily mixed gas flows upward in the mixing tank 11. During the flowing process of the gas, it pushes the driving impeller 21, the driving impeller 21 drives the rotating shaft 19, the rotating shaft 19 rotates inside the two limiting rings 18, and at the same time the rotating shaft 19 drives the mixing blades 20 to rotate, and the mixing blades 20 agitate the preliminarily mixed gas to achieve secondary full mixing of air and gas; The uniformly mixed gas can be evenly distributed in the main combustion chamber 31, thereby making the combustion process more uniform and there will be no situation where the temperature of some flames is relatively high, so as to reduce the generation rate and generation amount of nitrogen oxides.

[0021] In this embodiment, specifically: flow sensors are provided on the outer walls of the air inlet pipe 14 and the gas inlet pipe 15. The flow sensors and the proportioning valve 13 are both connected to the control system, and the control system controls the proportion of air and gas through a mixing ratio control algorithm; The mixing ratio control algorithm includes: Initialization settings Target mixing ratio setting: According to the specific requirements of the combustion equipment and the characteristics of the fuel, set the target mixing ratio of gas and air. For example, the target mixing ratio may be set to 1:10 (gas: air); Initial opening setting of proportional valve 13: Set the initial opening of proportional valve 13; the initial value of proportional valve 13 will be used as the starting point of the control algorithm; Sensor calibration: Ensure that the gas and air flow sensors have been calibrated to accurately measure the flow rate; Real-time data acquisition Flow rate reading: Read the current flow rates of gas and air in real time through the flow sensors, and these data will be used to calculate the actual mixing ratio; Status check: Check the operating status of devices such as proportional valve 13 and sensors to ensure they are working properly; Mixing ratio calculation Actual mixing ratio calculation: Calculate the current mixing ratio based on the real-time acquired gas and air flow rate data; for example, if the gas flow rate is 10 units and the air flow rate is 100 units, the actual mixing ratio is 1:10; Error analysis Error calculation: Compare the actual mixing ratio with the target mixing ratio to calculate the error; for example, if the target mixing ratio is 1:10 and the actual mixing ratio is 1:11, there is an error; Error direction judgment: Judge whether the error is a positive error (the actual ratio is higher than the target ratio) or a negative error (the actual ratio is lower than the target ratio); Control output calculation Control strategy selection: Select an appropriate control strategy based on the magnitude and direction of the error; in this algorithm, a proportional control strategy is mainly used; Calculation of the opening adjustment amount of proportional valve 13: Calculate the opening amount of proportional valve 13 that needs to be adjusted based on the error and the control strategy; for example, if there is a positive error, it may be necessary to reduce or increase the opening of proportional valve 13; Opening adjustment of proportional valve 13 Execution of opening adjustment: Adjust the opening of proportional valve 13 according to the calculated opening adjustment amount of proportional valve 13, which can be achieved by sending a control signal to the actuator of proportional valve 13; Opening limit processing: Ensure that the adjusted opening of proportional valve 13 is within the physical limit range to avoid equipment damage or control failure caused by excessive or too small opening; Loop execution and monitoring Loop execution: Repeat the above steps to achieve closed-loop control; by continuously collecting data, calculating errors, and adjusting the opening of proportional valve 13, the actual mixing ratio gradually approaches the target mixing ratio; Monitoring and alarm: During the control process, monitor key parameters (such as flow rate, pressure, temperature, etc.) and equipment status in real time. If abnormal situations (such as sensor failures, jams of proportional valve 13, etc.) are found, send alarm signals in time and take corresponding treatment measures.

[0022] By adopting the mixed ratio control algorithm, it has the following advantages: First, ensure the safety, stability and efficiency of the combustion process; The algorithm ensures that the combustion process is carried out under the optimal air-fuel ratio by adjusting the mixing ratio of gas and air in real time. On the one hand, accurate mixing ratio control can avoid incomplete combustion caused by excess gas or insufficient air, effectively prevent safety hazards such as carbon deposition and deflagration, and extend the service life of the equipment; on the other hand, the algorithm automatically optimizes the mixing ratio by dynamically responding to changes in combustion chamber temperature (such as combined with feedback from the temperature sensor 38), maintains flame stability, and reduces the negative impact of temperature fluctuations on combustion efficiency, thereby improving overall heat output and reducing fuel consumption; Second, to achieve the dual goals of environmentally friendly emissions and intelligent management; At the environmental protection level, the algorithm suppresses the formation of thermal nitrogen oxides by precisely controlling the mixing ratio. For example, in a gas boiler, the algorithm can cooperate with the full premixed combustion technology to control the combustion temperature within a reasonable range, reduce the high-temperature area, and thus significantly reduce the NOx emission concentration. At the management level, the algorithm is deeply integrated with the automatic control system to achieve closed-loop adjustment of the mixing ratio and reduce the need for manual intervention. At the same time, its data recording function can provide support for equipment performance analysis and fault warning, promote the upgrading of the combustion system to intelligent and low-emission directions, and assist in the green transformation of industrial production and energy utilization.

[0023] In this embodiment, specifically: the combustion assembly 301 includes a main combustion chamber 31, a diverter pipe 32, two air return pipes 33, a combustion hood 34, a main burner 35, a guide plate 36, a second air distribution plate 37, an exhaust hood 39 and two smoke exhaust holes 40; The guide plates 36 are fixedly connected to the inner front wall and the inner rear wall of the main combustion chamber 31. The guide plates 36 are arranged in a staggered manner. The guide plates 36 can guide the gas and extend the flow path of the gas so that the gas can be fully burned. One end of the delivery pipe 16 away from the mixing tank 11 is fixedly connected to the lower surface of the main combustion chamber 31 and communicates with the exhaust hood 39. The premixing chamber 12 is installed on the rear surface of the main combustion chamber 31. The main burner 35 is installed on one side of the main combustion chamber 31. The combustion hood 34 is fixedly connected to one side of the inner wall of the main combustion chamber 31 and corresponds to the position of the main burner 35. The second air distribution plate 37 is fixedly connected to the inner side wall of the main combustion chamber 31 and is located below the flow guide plate 36. The exhaust hood 39 is installed on the inner bottom wall of the main combustion chamber 31. The gas after secondary mixing by the air premixing assembly 101 flows into the exhaust hood 39 through the delivery pipe 16, and then flows into the main combustion chamber 31. At this time, the gas flows upward after passing through the second air distribution plate 37. The second air distribution plate 37 can make the gas flow upward evenly, and then the gas is burned by the main burner 35. Heat exchange pipes are arranged inside the main combustion chamber 31 to realize the heating of the water source; Two exhaust holes 40 are symmetrically opened on the upper surface of the shunt pipe 32. Two return pipes 33 are symmetrically located on both sides of the main combustion chamber 31. The top end of the return pipe 33 communicates with the outer wall of the shunt pipe 32, and the bottom end of the return pipe 33 communicates with the outer wall of the exhaust hood 39. When the gas flows from the exhaust hood 39 into the main combustion chamber 31, a negative pressure is generated at the bottom of the return pipe 33, thereby pushing the flue gas in the top shunt pipe 32. Part of the flue gas flows into the return pipe 33, and then flows into the main combustion chamber 31 again through the return pipe 33, thereby realizing the circulating combustion of the flue gas. By circulating the combustion of the flue gas, the oxygen concentration can be reduced, and the reactants in the combustion zone can be diluted, thereby reducing the generation of nitrogen oxides.

[0024] In this embodiment, specifically: a temperature sensor 38 is installed on one side of the main combustion chamber 31. The probe of the temperature sensor 38 is located inside the main combustion chamber 31. The model of the temperature sensor 38 is: LC-WRP; The working temperature inside the main combustion chamber 31 is monitored in real time by the temperature sensor 38. The temperature sensor 38 transmits the real-time monitored temperature data to the control system. The control system automatically adjusts the operating parameters of the main burner 35 according to the preset temperature range and control strategy, thereby realizing automatic control. This not only improves the stability and safety of the combustion process, but also reduces the difficulty and labor intensity of manual operation; By long-term monitoring and analysis of the temperature data, the operating rules and performance changes of the combustion equipment can be understood, providing data support for the maintenance, repair and upgrade of the equipment. At the same time, remote monitoring and fault diagnosis can also be realized, improving the intelligent level of equipment management.

[0025] In this embodiment, specifically: the burnout assembly 401 includes a secondary combustion chamber 41, a secondary burner 42, a third air distribution plate 43, a cover plate 44 and a smoke inlet pipe 45; The secondary burner 42 is installed on one side of the secondary combustion chamber 41, the third air distribution plate 43 is installed on the inner side wall of the secondary combustion chamber 41, the smoke inlet pipe 45 is installed on the upper surface of the cover plate 44, the secondary combustion chamber 41 is installed on the rear surface of the main combustion chamber 31, the cover plate 44 is installed on the upper surface of the secondary combustion chamber 41, the end of the secondary burner 42 is located below the third air distribution plate 43, one end of the smoke inlet pipe 45 far from the secondary combustion chamber 41 is installed on the upper surface of the shunt pipe 32 and is communicated with the shunt pipe 32. The flue gas generated after the gas burns sufficiently in the combustion assembly 301 flows into the interior of the secondary combustion chamber 41 through the smoke inlet pipe 45, and then flows downward after passing through the third air distribution plate 43. At this time, the secondary burner 42 can burn the flue gas again, thereby reducing the oxygen concentration again and reducing the generation of nitrogen oxides.

[0026] In this embodiment, specifically: a smoke exhaust pipe 46 is installed on the side of the secondary combustion chamber 41 far from the secondary burner 42, and the flue gas after combustion is discharged from the smoke exhaust pipe 46.

[0027] A low-emission gas combustion method includes the following steps: Initial air mixing: Use a proportional valve to control the air volume and gas volume entering the premixing chamber. The air and gas are initially mixed in the premixing chamber and flow into the mixing tank through the first air distribution plate for secondary mixing; Secondary air mixing: The preliminarily mixed gas pushes the drive impeller in the mixing tank. The drive impeller drives the mixing blades through the rotating shaft, and the mixing blades agitate the preliminarily mixed gas to achieve secondary full mixing; Initial combustion: The mixed gas flows from the exhaust hood into the main combustion chamber, flows upward evenly through the second air distribution plate, the main burner burns the gas, heats the heat exchange tubes in the main combustion chamber, and the generated flue gas flows into the shunt pipe; Flue gas circulating combustion: When the gas flows from the exhaust hood into the main combustion chamber, a negative pressure is generated at the bottom of the return pipe, and a part of the flue gas in the top shunt pipe flows into the return pipe and then flows into the main combustion chamber again through the return pipe to conduct circulating combustion on the flue gas; Secondary flue gas combustion: The flue gas flows into the secondary combustion chamber through the smoke inlet pipe, the secondary burner burns the flue gas again, reduces the oxygen concentration, dilutes the reactants in the combustion zone, and the flue gas after combustion is discharged from the smoke exhaust pipe.

[0028] Working principle or structural principle. During use, connect the air inlet pipe 14 to an external blower and connect the gas inlet pipe 15 to an external gas pipeline. Use the proportional valve 13 to precisely control the ratio of air and gas entering the premixing chamber 12. After the gas and air flow into the premixing chamber 12, the first air distribution plate 17 can enhance the initial mixing effect of air and gas; Then, the gas preliminarily mixed in the premixing chamber 12 flows into the mixing tank 11 for secondary mixing. At this time, the preliminarily mixed gas flows upward in the mixing tank 11. During the flowing process, the gas pushes the driving impeller 21. The driving impeller 21 drives the rotating shaft 19. The rotating shaft 19 rotates inside the two limiting rings 18. At the same time, the rotating shaft 19 drives the mixing blades 20 to rotate. The mixing blades 20 agitate the premixed gas, realizing the secondary full mixing of air and gas. The gas after secondary mixing by the air premixing assembly 101 flows into the exhaust hood 39 through the delivery pipe 16, and then flows into the main combustion chamber 31. At this time, the gas flows upward after passing through the second air distribution plate 37. The second air distribution plate 37 can make the gas flow upward evenly. Then, the gas is burned by the main burner 35. Heat exchange pipes are arranged inside the main combustion chamber 31, thus realizing the heating of the water source. When the gas flows from the exhaust hood 39 into the main combustion chamber 31, negative pressure is generated at the bottom of the return pipe 33, thereby sucking the flue gas in the top shunt pipe 32. Part of the flue gas flows into the return pipe 33 and then flows into the main combustion chamber 31 again through the return pipe 33, thus realizing the circulating combustion of the flue gas. The flue gas generated after the gas burns in the combustion assembly 301 flows into the inside of the secondary combustion chamber 41 through the smoke inlet pipe 45, and then flows downward after passing through the third air distribution plate 43. At this time, the secondary burner 42 can burn the flue gas again, thereby further reducing the oxygen concentration and reducing the generation of nitrogen oxides. The flue gas after combustion is discharged from the exhaust pipe 46.

[0029] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A combustion device for a low-emission gas boiler, characterized in that, It includes an air premixing component (101), a combustion component (301) and a burnout component (401). The air premixing component (101) is in communication with the combustion component (301), and the combustion component (301) is in communication with the burnout component (401). The air premixing component (101) includes a mixing tank (11), a premixing chamber (12), an air inlet pipe (14), a gas inlet pipe (15), a first air distribution plate (17), two limiting rings (18), a rotating shaft (19), mixing blades (20) and a driving impeller (21). The air inlet pipe (14) and the gas inlet pipe (15) are both installed on the lower surface of the premixing chamber (12). Proportioning valves (13) are installed on the outer side walls of the air inlet pipe (14) and the gas inlet pipe (15). The first air distribution plate (17) is installed inside the premixing chamber (12). The mixing tank (11) is installed on the upper surface of the premixing chamber (12) and is in communication with the premixing chamber (12). The rotating shaft (19) is rotatably connected inside the two limiting rings (18). The mixing blades (20) are fixedly connected to the outer side wall of the rotating shaft (19). The driving impeller (21) is fixedly connected to the outer side wall of the rotating shaft (19).

2. The combustion device of a low-emission gas boiler according to claim 1, characterized in that, The two limiting rings (18) are symmetrically and fixedly connected to the inner side wall of the mixing tank (11). A conveying pipe (16) is installed on the upper surface of the mixing tank (11).

3. A low-emission gas boiler combustion device according to claim 2, characterized in that, The combustion component (301) includes a main combustion chamber (31), a shunt pipe (32), two return pipes (33), a combustion hood (34), a main burner (35), a baffle plate (36), a second air distribution plate (37), an exhaust hood (39) and two exhaust holes (40). The baffle plate (36) is fixedly connected to the inner front wall and the inner rear wall of the main combustion chamber (31). The baffle plates (36) are arranged in a staggered manner. The main burner (35) is installed on one side of the main combustion chamber (31). The combustion hood (34) is fixedly connected to one side of the inner wall of the main combustion chamber (31) and corresponds to the position of the main burner (35). The second air distribution plate (37) is fixedly connected to the inner side wall of the main combustion chamber (31) and is located below the baffle plate (36). The exhaust hood (39) is installed on the inner bottom wall of the main combustion chamber (31). The two exhaust holes (40) are symmetrically opened on the upper surface of the shunt pipe (32). The two return pipes (33) are symmetrically located on both sides of the main combustion chamber (31).

4. The combustion device of a low-emission gas boiler according to claim 3, characterized in that, The top end of the return pipe (33) is in communication with the outer wall of the shunt pipe (32), and the bottom end of the return pipe (33) is in communication with the outer wall of the exhaust hood (39).

5. The combustion device of a low-emission gas boiler according to claim 4, characterized in that, One end of the conveying pipe (16) far from the mixing tank (11) is fixedly connected to the lower surface of the main combustion chamber (31) and is in communication with the exhaust hood (39). The premixing chamber (12) is installed on the rear surface of the main combustion chamber (31).

6. The combustion device of a low-emission gas boiler according to claim 5, characterized in that, A temperature sensor (38) is installed on one side of the main combustion chamber (31), and the probe of the temperature sensor (38) is located inside the main combustion chamber (31).

7. The combustion device of a low-emission gas boiler according to claim 3, characterized in that, The burnout component (401) includes a secondary combustion chamber (41), a secondary burner (42), a third air distribution plate (43), a cover plate (44), and a smoke inlet pipe (45). The secondary burner (42) is installed on one side of the secondary combustion chamber (41), the third air distribution plate (43) is installed on the inner side wall of the secondary combustion chamber (41), the smoke inlet pipe (45) is installed on the upper surface of the cover plate (44), and the secondary combustion chamber (41) is installed on the rear surface of the main combustion chamber (31).

8. A low-emission gas boiler combustion device according to claim 7, characterized in that, The cover plate (44) is installed on the upper surface of the secondary combustion chamber (41), the end of the secondary burner (42) is located below the third air distribution plate (43), and a smoke exhaust pipe (46) is installed on one side of the secondary combustion chamber (41) away from the secondary burner (42).

9. A combustion device for a low-emission gas boiler according to claim 8, characterized in that, One end of the smoke inlet pipe (45) away from the secondary combustion chamber (41) is installed on the upper surface of the shunt pipe (32) and is communicated with the shunt pipe (32).

10. A low-emission gas combustion method, applied to a low-emission gas boiler combustion device according to any one of claims 1-9, characterized in that, It includes the following steps: Initial air mixing: The proportional valve is used to control the air volume and gas volume entering the premixing chamber. Air and gas are preliminarily mixed in the premixing chamber and then flow into the mixing tank through the first air distribution plate for secondary mixing. Secondary air mixing: The preliminarily mixed gas pushes the drive impeller in the mixing tank. The drive impeller drives the mixing blades through the rotating shaft, and the mixing blades agitate the preliminarily mixed gas to achieve secondary full mixing. Initial combustion: The mixed gas flows from the exhaust hood into the main combustion chamber, uniformly flows upward through the second air distribution plate, and the main burner burns the gas, heats the heat exchange pipes in the main combustion chamber, and the generated flue gas flows into the shunt pipe. Flue gas circulating combustion: When the gas flows from the exhaust hood into the main combustion chamber, a negative pressure is generated at the bottom of the return pipe. A part of the flue gas in the top shunt pipe flows into the return pipe and then flows into the main combustion chamber again through the return pipe for circulating combustion of the flue gas. Secondary flue gas combustion: The flue gas flows into the secondary combustion chamber through the smoke inlet pipe, and the secondary burner burns the flue gas again to reduce the oxygen concentration and dilute the reactants in the combustion zone. The burned flue gas is discharged from the smoke exhaust pipe.

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