Low-emission gas boiler combustion device and method

Abstract

The present invention discloses a low-emission gas boiler combustion device and method thereof, comprising an air premixing component, a combustion component and a burnout component, wherein the air premixing component is connected to the combustion component, and the combustion component is connected to the burnout component; the air premixing component comprises a mixing tank, a premixing chamber, an air intake pipe, a gas intake pipe, a first air distribution plate, two limiting rings, a rotating shaft, a mixing blade and a driving impeller; the air intake pipe and the gas intake pipe are both installed on the lower surface of the premixing chamber. The premixing chamber of the present invention premixes the gas and air, and then the gas preliminarily mixed in the premixing chamber flows into the mixing tank for secondary mixing. After uniform mixing, the gas can be evenly distributed in the main combustion chamber, and thus there will be no excessively high or low gas concentration in local areas. 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.

Description

Technical Field

[0001] The present invention relates to a combustion device and a method thereof, in particular 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-fired boiler is a heat energy conversion device that burns gas (such as natural gas or liquefied petroleum gas) to heat water into hot water or steam for heating, bathing, or industrial purposes. Its core consists of a "pot" (water container) and a "furnace" (combustion chamber), supplemented by control systems and safety devices. During operation, a gas-fired boiler burns gas in the combustion chamber to produce high-temperature flue gas. A heat exchanger transfers this heat to the water in the water circulation system, generating hot water or steam.

[0003] Gas boiler combustion devices produce nitrogen oxides during operation, primarily thermal nitrogen oxides, which are formed by the oxidation of nitrogen dioxide 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 produced. When the temperature is below 1000K (approximately 700 degrees Celsius), the amount of nitrogen oxides produced is very small. However, when the temperature reaches around 1500°C, the reaction rate increases by 6-7 times for every 100°C increase in temperature, and the amount of nitrogen oxides produced increases rapidly.

[0004] To reduce nitrogen oxide emissions, existing technologies often use staged combustion technology and flue gas recirculation technology to treat the combustion process. Staged combustion technology divides the combustion process into multiple stages, such as the main combustion zone, the reburning zone, and the burnout zone. In the main combustion zone, the air supply is reduced to cause the fuel to burn in an oxygen-deficient or oxygen-depleted state, thereby lowering the combustion temperature. Flue gas recirculation technology reintroduces partially burned flue gas into the combustion zone to reduce the oxygen concentration and dilute the reactants in the combustion zone, thereby reducing the formation of nitrogen oxides.

[0005] 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 excessively high or low gas concentrations 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 generation 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, an 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 method thereof are proposed. Summary of the Invention

[0006] The object of the present invention is to provide a low-emission gas boiler combustion device and method thereof to solve one of the problems raised in the above background technology.

[0007] 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, wherein the air premixing component is connected to the combustion component, and the combustion component is connected to the burnout component;

[0008] The air premixing assembly 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;

[0009] The air intake pipe and the gas intake pipe are both installed on the lower surface of the premixing chamber, and the outer walls of the air intake pipe and the gas intake pipe are both installed with proportional valves. The first air distribution plate is installed inside the premixing chamber, and the mixing tank is installed on the upper surface of the premixing chamber and is connected to the premixing chamber. The rotating shaft is rotatably connected to the inside of the two limiting rings, the mixing blades are fixedly connected to the outer wall of the rotating shaft, and the driving impeller is fixedly connected to the outer wall of the rotating shaft.

[0010] As a further preferred embodiment of the present technical solution: the two limiting rings are symmetrically fixedly connected to the inner wall of the mixing tank, and a delivery pipe is installed on the upper surface of the mixing tank.

[0011] As a further preferred embodiment of the present technical solution: the combustion assembly includes a main combustion chamber, a diverter pipe, two air return pipes, a combustion hood, a main burner, a guide plate, a second air distribution plate, an exhaust hood and two smoke exhaust holes;

[0012] The guide plates are fixedly connected to the inner front wall and the inner rear wall of the main combustion chamber, the guide plates are staggered, 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 wall of the main combustion chamber and is located below the guide 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 diversion pipe, and the two return air pipes are symmetrically located on both sides of the main combustion chamber.

[0013] As a further preferred embodiment of the present technical solution: the top end of the return air pipe is communicated with the outer wall of the diversion pipe, and the bottom end of the return air pipe is communicated with the outer wall of the exhaust hood.

[0014] As a further preferred embodiment of the present technical solution: one end of the delivery pipe away from the mixing tank is fixedly connected to the lower surface of the main combustion chamber and communicated with the exhaust hood, and the premixing chamber is installed on the rear surface of the main combustion chamber.

[0015] As a further preferred embodiment of the present technical solution: a temperature sensor is installed on one side of the main combustion chamber, and a probe of the temperature sensor is located inside the main combustion chamber.

[0016] As a further preferred embodiment of the present technical solution: the burnout assembly includes an auxiliary combustion chamber, an auxiliary burner, a third air distribution plate, a cover plate and a smoke inlet pipe;

[0017] The auxiliary burner is installed on one side of the auxiliary combustion chamber, the third air distribution plate is installed on the inner wall of the auxiliary combustion chamber, the smoke inlet pipe is installed on the upper surface of the cover plate, and the auxiliary combustion chamber is installed on the rear surface of the main combustion chamber.

[0018] As a further preferred embodiment of the present technical solution: the cover plate is installed on the upper surface of the auxiliary combustion chamber, the end of the auxiliary burner is located below the third air distribution plate, and a smoke exhaust pipe is installed on the side of the auxiliary combustion chamber away from the auxiliary burner.

[0019] As a further preferred embodiment of the present technical solution: one end of the smoke inlet pipe away from the auxiliary combustion chamber is installed on the upper surface of the diverter pipe and is in communication with the diverter pipe.

[0020] A low-emission gas combustion method comprises the following steps:

[0021] Air primary mixing: A proportional valve is used to control the amount of air and gas entering the premixing chamber. The air and gas are initially mixed in the premixing chamber and then flow into the mixing tank for secondary mixing after passing through the first air distribution plate.

[0022] Secondary air mixing: The initially mixed gas pushes the driving impeller in the mixing tank, and the driving impeller drives the mixing blades through the rotating shaft. The mixing blades stir the mixed gas after the initial mixing to achieve secondary full mixing;

[0023] Primary combustion: The mixed gas flows from the exhaust hood into the main combustion chamber, flows upward evenly through the second air distribution plate, and the main burner burns the gas, heating the heat exchange tubes in the main combustion chamber, and the generated flue gas flows into the diversion pipe;

[0024] Flue gas circulation combustion: When the gas flows from the exhaust hood into the main combustion chamber, negative pressure is generated at the bottom of the return air pipe. Part of the flue gas in the top diversion pipe flows into the return air pipe, and then flows into the main combustion chamber again through the return air pipe, so that the flue gas is circulated and burned;

[0025] Secondary combustion of flue gas: Flue gas flows into the auxiliary combustion chamber through the smoke inlet pipe, and the auxiliary burner burns the flue gas again to reduce the oxygen concentration and dilute the reactants in the combustion zone. The combusted flue gas is discharged from the exhaust pipe.

[0026] Advantages of the present invention:

[0027] 1. The present invention premixes gas and air through a premixing chamber, and precisely controls the ratio of air and gas entering the premixing chamber through a proportional valve. The gas preliminarily mixed in the premixing chamber then flows into a mixing tank for secondary mixing. At this time, the preliminarily mixed gas flows upward in the mixing tank, and the gas drives the impeller during the flow. With the cooperation of the rotating shaft, the limit ring, the mixing blades and other structures, the preliminarily mixed mixed gas can be stirred to achieve secondary sufficient mixing of the air and gas. After uniform mixing, the gas can be evenly distributed in the main combustion chamber, and thus there will be no excessively high or low gas concentration in local areas. This uniform gas distribution can make the combustion process more uniform, and there will be no situation where the flame temperature is relatively high in some areas, thereby reducing the generation rate and amount of nitrogen oxides.

[0028] 2. The secondary mixed gas of the present invention flows into the exhaust hood through the delivery pipe, and then flows into the main combustion chamber. At this time, the gas flows upward after passing through the second air distribution plate. The second air distribution plate can make the gas flow upward evenly, and then the gas is burned by the 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 air pipe, and then a part of the flue gas in the top diversion pipe flows into the return air pipe, and then flows into the main combustion chamber again through the return air pipe, thereby 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

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is a structural schematic diagram of a low-emission gas boiler combustion device of the present invention;

[0031] Figure 2 This is a schematic diagram of the installation position of the air return pipe of the present invention;

[0032] Figure 3 This is a schematic structural diagram of the air premixing assembly of the present invention;

[0033] Figure 4 This is a schematic diagram of the exploded structure of the air premixing assembly of the present invention;

[0034] Figure 5 This is a schematic diagram of the driving impeller structure of the present invention;

[0035] Figure 6It is a schematic structural diagram of the combustion assembly of the present invention;

[0036] Figure 7 Schematic diagram of the shunt pipe structure of the present invention;

[0037] Figure 8 It is a schematic diagram of the decomposition structure of the burnout assembly of the present invention.

[0038] In the figure: 101, air premixing assembly; 11, mixing tank; 12, premixing chamber; 13, proportional valve; 14, air inlet pipe; 15, gas inlet pipe; 16, delivery pipe; 17, first air distribution plate; 18, limit ring; 19, rotating shaft; 20, mixing blade; 21, driving impeller; 301, combustion assembly; 31, main combustion chamber; 32, diverter pipe; 33, return air 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 assembly; 41, auxiliary combustion chamber; 42, auxiliary burner; 43, third air distribution plate; 44, cover plate; 45, smoke inlet pipe; 46, smoke exhaust pipe. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0040] Example

[0041] See also Figures 1-8 The present invention provides a technical solution: a low-emission gas boiler combustion device, comprising an air premixing component 101, a combustion component 301 and a burnout component 401, wherein the air premixing component 101 is connected to the combustion component 301, and the combustion component 301 is connected to the burnout component 401;

[0042] The air premixing assembly 101 is used to mix air and gas. After uniform mixing, the gas can be evenly distributed in the main combustion chamber 31, thereby preventing local areas of excessively high or low gas concentrations. This uniform gas distribution can make the combustion process more uniform, eliminating the situation where the flame temperature is relatively high in some areas, thereby reducing the generation rate and amount of nitrogen oxides.

[0043] The combustion assembly 301 is used to realize the combustion of the gas. A portion of the flue gas generated after the combustion of the gas can flow back into the interior of the main combustion chamber 31. 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.

[0044] The burnout component 401 is used to re-burn the exhausted flue gas, thereby further reducing the oxygen concentration and reducing the generation of nitrogen oxides;

[0045] The air premixing assembly 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;

[0046] The air intake pipe 14 and the gas intake pipe 15 are both installed on the lower surface of the premixing chamber 12. A proportional valve 13 is installed on the outer wall of the air intake pipe 14 and the gas intake pipe 15. The air intake pipe 14 is connected to an external blower, and the gas intake pipe 15 is connected to an external gas pipeline. The proportional valve 13 can accurately control the ratio of air and gas entering the premixing chamber 12. By accurately controlling the mixing ratio of gas and air, it can ensure that the combustion process is carried out under the optimal air-fuel ratio condition, so that the gas can be fully burned, the combustion efficiency is improved, and the generation of incomplete combustion products is reduced. At the same time, due to more uniform combustion, the flame temperature is effectively controlled, and the generation of high-temperature hot spots is avoided, thereby significantly reducing the generation rate and emission concentration of thermal nitrogen oxides, which helps to achieve a more environmentally friendly and efficient combustion process.

[0047] The first air distribution plate 17 is installed inside the premixing chamber 12. The first air distribution plate 17 can enhance the initial mixing effect of air and gas.

[0048] 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 to the inside of 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. The two limiting rings 18 are symmetrically 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. 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. The gas pushes the driving impeller 21 during the flow process. 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 stir the mixed gas after the initial mixing to achieve secondary full mixing of air and gas.

[0049] The evenly mixed gas can be evenly distributed in the main combustion chamber 31, thereby making the combustion process more uniform and preventing the situation where the temperature of some parts of the flame is relatively high, thereby reducing the generation rate and amount of nitrogen oxides.

[0050] In this embodiment, specifically: flow sensors are provided on the outer walls of the air intake pipe 14 and the gas intake pipe 15, and the flow sensors and the proportional valve 13 are both connected to the control system, which controls the ratio of air to gas through a mixing ratio control algorithm;

[0051] The mixture ratio control algorithm includes:

[0052] Initialization settings

[0053] Target mixture ratio setting: According to the specific requirements of the combustion equipment and the characteristics of the fuel, the target mixture ratio of gas and air is set. For example, the target mixture ratio may be set to 1:10 (gas:air);

[0054] Initial opening setting of proportional valve 13: Set the initial opening of proportional valve 13; the initial value of proportional valve 13 will serve as the starting point of the control algorithm;

[0055] Sensor calibration: Ensure that the gas and air flow sensors have been calibrated and can accurately measure flow;

[0056] Real-time data collection

[0057] Flow reading: The current flow of gas and air is read in real time through the flow sensor. These data will be used to calculate the actual mixing ratio;

[0058] Status check: Check the operating status of the proportional valve 13, sensor and other equipment to ensure they are working properly;

[0059] Mixing ratio calculation

[0060] Actual mixing ratio calculation: Calculate the current mixing ratio based on the real-time collected gas and air flow data; for example, if the gas flow is 10 units and the air flow is 100 units, the actual mixing ratio is 1:10;

[0061] Error analysis

[0062] Error calculation: The actual mix ratio is compared to the target mix ratio and the error is calculated; for example, if the target mix ratio is 1:10 and the actual mix ratio is 1:11, there is an error;

[0063] Error direction judgment: Determine whether the error is positive (the actual ratio is higher than the target ratio) or negative (the actual ratio is lower than the target ratio);

[0064] Control output calculation

[0065] Control strategy selection: Select the appropriate control strategy based on the size and direction of the error; in this algorithm, the proportional control strategy is mainly used;

[0066] Calculation of the opening adjustment of the proportional valve 13: Based on the error and control strategy, the amount of opening of the proportional valve 13 that needs to be adjusted is calculated. For example, if there is a positive error, the opening of the proportional valve 13 may need to be reduced or increased.

[0067] Proportional valve 13 opening adjustment

[0068] Opening adjustment execution: adjusting the opening of the proportional valve 13 according to the calculated opening adjustment amount of the proportional valve 13, which can be achieved by sending a control signal to the actuator of the proportional valve 13;

[0069] Opening limit processing: Ensure that the opening of the proportional valve 13 after adjustment is within the physical limit range to avoid equipment damage or control failure caused by excessive or insufficient opening;

[0070] Loop execution and monitoring

[0071] Circular execution: Repeat the above steps to achieve closed-loop control; by continuously collecting data, calculating errors, and adjusting the opening of the proportional valve 13, the actual mixing ratio gradually approaches the target mixing ratio;

[0072] Monitoring and alarm: During the control process, key parameters (such as flow, pressure, temperature, etc.) and equipment status are monitored in real time. If any abnormal situation is found (such as sensor failure, proportional valve 13 stuck, etc.), an alarm signal will be issued in time and corresponding treatment measures will be taken.

[0073] By adopting the mixed ratio control algorithm, it has the following advantages:

[0074] First, ensure the safety, stability and efficiency of the combustion process;

[0075] The algorithm ensures that the combustion process proceeds under optimal air-fuel ratio conditions by adjusting the gas-air mixture ratio in real time. On the one hand, precise mixture ratio control can avoid incomplete combustion caused by excess gas or insufficient air, effectively prevent safety hazards such as carbon deposits and deflagration, and extend the service life of the equipment. On the other hand, the algorithm dynamically responds to changes in combustion chamber temperature (for example, in combination with feedback from temperature sensor 38) to automatically optimize the mixture ratio, maintain flame stability, and reduce the negative impact of temperature fluctuations on combustion efficiency, thereby improving overall heat output and reducing fuel consumption.

[0076] Second, achieving the dual goals of environmentally friendly emissions and intelligent management;

[0077] At the environmental protection level, the algorithm suppresses the formation of thermal nitrogen oxides by precisely controlling the mixing ratio. For example, in gas boilers, 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 upgrade of the combustion system to intelligent and low-emission directions, and assist in the green transformation of industrial production and energy utilization.

[0078] 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 cover 34, a main burner 35, a guide plate 36, a second air distribution plate 37, an exhaust cover 39 and two smoke exhaust holes 40;

[0079] 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 staggered and can guide the gas, thereby extending the flow path of the gas and ensuring that the gas can be fully burned.

[0080] The 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 wall of the main combustion chamber 31 and is located below the guide plate 36, and the exhaust hood 39 is installed on the inner bottom wall of the main combustion chamber 31, and the gas after secondary mixing through 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 evenly upward, and then the gas is burned by the main burner 35. A heat exchange pipe is provided inside the main combustion chamber 31 to achieve heating of the water source;

[0081] Two smoke exhaust holes 40 are symmetrically opened on the upper surface of the diverter pipe 32, and two return air pipes 33 are symmetrically located on both sides of the main combustion chamber 31. The top end of the return air pipe 33 is connected to the outer wall of the diverter pipe 32, and the bottom end of the return air pipe 33 is connected to 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 air pipe 33, and then a part of the flue gas in the top diverter pipe 32 flows into the return air pipe 33, and then flows into the main combustion chamber 31 again through the return air pipe 33, thereby realizing the circulating combustion of the flue gas. By circulating 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.

[0082] In this embodiment, specifically: a temperature sensor 38 is installed on one side of the main combustion chamber 31, and a probe of the temperature sensor 38 is located inside the main combustion chamber 31. The model of the temperature sensor 38 is: LC-WRP;

[0083] The operating temperature in 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 automated control. This not only improves the stability and safety of the combustion process, but also reduces the difficulty and labor intensity of manual operation.

[0084] Through long-term monitoring and analysis of temperature data, we can understand the operating patterns and performance changes of combustion equipment, provide data support for equipment maintenance, care and upgrades, and at the same time, realize remote monitoring and fault diagnosis, and improve the intelligent level of equipment management.

[0085] In this embodiment, specifically: the burnout assembly 401 includes an auxiliary combustion chamber 41, an auxiliary burner 42, a third air distribution plate 43, a cover plate 44 and a smoke inlet pipe 45;

[0086] The auxiliary burner 42 is installed on one side of the auxiliary combustion chamber 41, the third air distribution plate 43 is installed on the inner wall of the auxiliary combustion chamber 41, the smoke inlet pipe 45 is installed on the upper surface of the cover plate 44, the auxiliary combustion chamber 41 is installed on the rear surface of the main combustion chamber 31, and the cover plate 44 is installed on the upper surface of the auxiliary combustion chamber 41. The end of the auxiliary burner 42 is located below the third air distribution plate 43, and the end of the smoke inlet pipe 45 away from the auxiliary combustion chamber 41 is installed on the upper surface of the diversion pipe 32 and connected to the diversion pipe 32. The flue gas generated after the gas is fully burned in the combustion assembly 301 flows into the interior of the auxiliary 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 flue gas can be burned again by the auxiliary burner 42, thereby reducing the oxygen concentration again and reducing the generation of nitrogen oxides.

[0087] In this embodiment, specifically: a smoke exhaust pipe 46 is installed on a side of the auxiliary combustion chamber 41 away from the auxiliary burner 42 , and smoke after combustion is discharged from the smoke exhaust pipe 46 .

[0088] A low-emission gas combustion method comprises the following steps:

[0089] Air primary mixing: A proportional valve is used to control the amount of air and gas entering the premixing chamber. The air and gas are initially mixed in the premixing chamber and then flow into the mixing tank for secondary mixing after passing through the first air distribution plate.

[0090] Secondary air mixing: The initially mixed gas pushes the driving impeller in the mixing tank, and the driving impeller drives the mixing blades through the rotating shaft. The mixing blades stir the mixed gas after the initial mixing to achieve secondary full mixing;

[0091] Primary combustion: The mixed gas flows from the exhaust hood into the main combustion chamber, flows upward evenly through the second air distribution plate, and the main burner burns the gas, heating the heat exchange tubes in the main combustion chamber, and the generated flue gas flows into the diversion pipe;

[0092] Flue gas circulation combustion: When the gas flows from the exhaust hood into the main combustion chamber, negative pressure is generated at the bottom of the return air pipe. Part of the flue gas in the top diversion pipe flows into the return air pipe, and then flows into the main combustion chamber again through the return air pipe, so that the flue gas is circulated and burned;

[0093] Secondary combustion of flue gas: Flue gas flows into the auxiliary combustion chamber through the smoke inlet pipe, and the auxiliary burner burns the flue gas again to reduce the oxygen concentration and dilute the reactants in the combustion zone. The combusted flue gas is discharged from the exhaust pipe.

[0094] The working principle or structural principle is that when in use, the air inlet pipe 14 is connected to the external blower, and the gas inlet pipe 15 is connected to the external gas pipeline. The ratio of air and gas entering the premixing chamber 12 is precisely controlled by the proportional valve 13. After the gas and air flow into the premixing chamber 12, the first air distribution plate 17 can enhance the initial mixing effect of the air and gas.

[0095] Then, the preliminarily mixed gas 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 flow, the gas pushes the driving impeller 21, which 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 stir the preliminarily mixed mixed gas to achieve secondary full mixing of the air and gas.

[0096] The gas after secondary mixing in 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. A heat exchange pipe is provided inside the main combustion chamber 31 to achieve heating of the water source. When the gas flows into the main combustion chamber 31 from the exhaust hood 39, a negative pressure is generated at the bottom of the return pipe 33, and then a part of the flue gas in the top diversion pipe 32 flows into the return pipe 33, and then flows into the main combustion chamber 31 again through the return pipe 33, thereby achieving circulating combustion of the flue gas. The flue gas generated after the gas is burned in the combustion assembly 301 flows into the interior of the auxiliary 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 flue gas can be burned again by the auxiliary burner 42, thereby reducing the oxygen concentration again and reducing the generation of nitrogen oxides. The flue gas after combustion is discharged from the exhaust pipe 46.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A low-emission gas boiler combustion device, characterized in that: It comprises an air premixing component (101), a combustion component (301) and a burnout component (401), wherein 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 assembly (101) comprises a mixing tank (11), a premixing chamber (12), an air intake pipe (14), a gas intake pipe (15), a first air distribution plate (17), two limiting rings (18), a rotating shaft (19), a mixing blade (20) and a driving impeller (21); The air intake pipe (14) and the gas intake pipe (15) are both installed on the lower surface of the premixing chamber (12); the outer walls of the air intake pipe (14) and the gas intake pipe (15) are both installed with proportional valves (13); 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 to the inside of the two limiting rings (18); the mixing blades (20) are fixedly connected to the outer wall of the rotating shaft (19); and the driving impeller (21) is fixedly connected to the outer wall of the rotating shaft (19); The combustion assembly (301) includes a main combustion chamber (31), a diverter pipe (32), two return air 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 plate (36) is fixedly connected to the inner front wall and the inner rear wall of the main combustion chamber (31), the guide plates (36) are staggered, the main burner (35) is installed on one side of the main combustion chamber (31), and the combustion hood (34) is fixedly connected to one side of the inner wall of the main combustion chamber (31). The second air distribution plate (37) is fixedly connected to the inner wall of the main combustion chamber (31) and is located below the guide plate (36), and the exhaust hood (39) is installed on the inner bottom wall of the main combustion chamber (31). The two smoke exhaust holes (40) are symmetrically opened on the upper surface of the diverter pipe (32). The two return air pipes (33) are symmetrically located on both sides of the main combustion chamber (31). The top end of the return air pipe (33) is connected to the outer wall of the diverter pipe (32), and the bottom end of the return air pipe (33) is connected to the outer wall of the exhaust hood (39). The burnout assembly (401) includes an auxiliary combustion chamber (41), an auxiliary burner (42), a third air distribution plate (43), a cover plate (44) and a smoke inlet pipe (45); the auxiliary burner (42) is installed on one side of the auxiliary combustion chamber (41), the third air distribution plate (43) is installed on the inner wall of the auxiliary combustion chamber (41), the smoke inlet pipe (45) is installed on the upper surface of the cover plate (44), and the auxiliary combustion chamber (41) is installed on the rear surface of the main combustion chamber (31).

2. A low-emission gas boiler combustion device according to claim 1, characterized in that: The two limiting rings (18) are symmetrically fixedly connected to the inner wall of the mixing tank (11), and a delivery 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: 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), and the premixing chamber (12) is installed on the rear surface of the main combustion chamber (31).

4. A low-emission gas boiler combustion device according to claim 3, characterized in that: A temperature sensor (38) is installed on one side of the main combustion chamber (31), and a probe of the temperature sensor (38) is located inside the main combustion chamber (31).

5. A low-emission gas boiler combustion device according to claim 1, characterized in that: The cover plate (44) is installed on the upper surface of the auxiliary combustion chamber (41), the end of the auxiliary burner (42) is located below the third air distribution plate (43), and a smoke exhaust pipe (46) is installed on the side of the auxiliary combustion chamber (41) away from the auxiliary burner (42).

6. A low-emission gas boiler combustion device according to claim 5, characterized in that: One end of the smoke inlet pipe (45) away from the auxiliary combustion chamber (41) is mounted on the upper surface of the diverter pipe (32) and is in communication with the diverter pipe (32).

7. A low-emission gas combustion method, applied to a low-emission gas boiler combustion device according to any one of claims 1 to 6, characterized in that: The following steps are involved: Air primary mixing: A proportional valve is used to control the amount of air and gas entering the premixing chamber. The air and gas are initially mixed in the premixing chamber and then flow into the mixing tank for secondary mixing after passing through the first air distribution plate. Secondary air mixing: The initially mixed gas pushes the driving impeller in the mixing tank, and the driving impeller drives the mixing blades through the rotating shaft. The mixing blades stir the mixed gas after the initial mixing to achieve secondary full mixing; Primary combustion: The mixed gas flows from the exhaust hood into the main combustion chamber, flows upward evenly through the second air distribution plate, and the main burner burns the gas, heating the heat exchange tubes in the main combustion chamber, and the generated flue gas flows into the diversion pipe; Flue gas circulation combustion: When the gas flows from the exhaust hood into the main combustion chamber, negative pressure is generated at the bottom of the return air pipe. Part of the flue gas in the top diversion pipe flows into the return air pipe, and then flows into the main combustion chamber again through the return air pipe, so that the flue gas is circulated and burned; Secondary combustion of flue gas: Flue gas flows into the auxiliary combustion chamber through the smoke inlet pipe, and the auxiliary burner burns the flue gas again to reduce the oxygen concentration and dilute the reactants in the combustion zone. The combusted flue gas is discharged from the exhaust pipe.

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