Air-staged porous medium combustion device

Abstract

The utility model discloses an air classification porous medium combustion device which comprises a shell, a first porous medium, a second porous medium, a third porous medium and an air inlet pipe, and the shell is provided with a cavity, an air inlet end and an air outlet end. The air inlet end and the air outlet end are communicated with the cavity, the air inlet end is arranged below the air outlet end, the first porous medium, the second porous medium and the third porous medium are sequentially arranged from bottom to top, the aperture of the third porous medium is smaller than that of the first porous medium, and the aperture of the first porous medium is smaller than that of the second porous medium. One end of the air inlet pipe penetrates through the third porous medium to be communicated with the second porous medium, the other end of the air inlet pipe penetrates through the air outlet end, the peripheral face of the air inlet pipe and the air outlet end are arranged at intervals, and the air inlet pipe is suitable for introducing secondary air. The porous medium combustion device with the air classification function has the advantages of being simple in structure, low in cost, stable in combustion and the like.

Description

Technical Field

[0001] The utility model relates to the fields of waste treatment and energy utilization, and in particular to an air-classified porous medium combustion device. Background Art

[0002] Porous media combustion technology has the advantages of strong combustion stability, high combustion rate and low pollutant emissions. It has broad application prospects in industrial low calorific value waste gas treatment and high-efficiency burner design.

[0003] In related technologies, porous media combustion devices have limited ability to control the combustion state of fuel, and are difficult to solve the problems of poor stability and excessive NOx emissions in the combustion of ammonia or extremely low calorific value fuels, and their applicability is limited. Utility Model Content

[0004] The utility model aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an embodiment of the present invention proposes an air-graded porous medium combustion device that can precisely control the combustion state and has a highly uniform temperature distribution inside the burner.

[0006] The air-staged porous medium combustion device according to an embodiment of the present invention comprises: a shell having a chamber, an air inlet end and an air outlet end, the air inlet end and the air outlet end are both communicated with the chamber and the air inlet end is arranged below the air outlet end, the air inlet end is suitable for introducing mixed fuel gas, and the air outlet end is suitable for exhausting smoke; a first porous medium, a second porous medium and a third porous medium, the first porous medium, the second porous medium and the third porous medium are all arranged in the shell and located between the air inlet end and the air outlet end, the first porous medium, the second porous medium and the third porous medium are The third porous medium is arranged in sequence from bottom to top, the pore size of the third porous medium is smaller than the pore size of the first porous medium, and the pore size of the first porous medium is smaller than the pore size of the second porous medium; an air intake pipe, one end of the air intake pipe passes through the third porous medium and is connected to the second porous medium, the other end of the air intake pipe is passed through the air outlet end, and the outer peripheral surface of the air intake pipe is spaced apart from the air outlet end so that the flue gas is discharged from the chamber between the air intake pipe and the air outlet end, and the air intake pipe is suitable for introducing secondary air to provide secondary air for the fuel in the second porous medium.

[0007] The air-staged porous medium combustion device of the embodiment of the utility model is provided with a first porous medium, a second porous medium, a third porous medium and an air inlet pipe. The air and secondary air ratio is controlled according to different fuel types, air temperatures and expected outlet temperatures, so that a suitable combustion atmosphere and temperature field distribution are created in the first porous medium and the second porous medium, thereby achieving adaptation to various fuels and working conditions and improving the applicability of the air-staged porous medium combustion device.

[0008] In some embodiments, the chamber is divided into a first chamber, a second chamber, and a third chamber along the up and down directions, the first chamber is located below the second chamber, the second chamber is located below the third chamber, and the first porous medium, the second porous medium, and the third porous medium are all arranged in the second chamber.

[0009] In some embodiments, the inner circumference of the first cavity gradually increases from bottom to top, and the air inlet is connected to the first cavity, and / or the inner circumference of the third cavity gradually decreases from bottom to top, and the air outlet is connected to the third cavity.

[0010] In some embodiments, the shell includes an outer shell and an insulation layer, the insulation layer is arranged in the outer shell, and the insulation layer is used to keep the chamber warm.

[0011] In some embodiments, the air-staged porous media combustion device further includes: a first perforated plate disposed in the chamber and below the first porous medium; and / or a second perforated plate disposed in the chamber and above the third porous medium.

[0012] In some embodiments, both the first orifice plate and the second orifice plate are honeycomb porous plates.

[0013] In some embodiments, the pore size of the first orifice plate is less than 1 mm.

[0014] In some embodiments, the inner circumferential surface of the shell is provided with a flange extending along its circumference, and the lower side of the first porous medium abuts against the upper end of the flange so that the first porous medium is installed in the shell.

[0015] In some embodiments, the pore density of the first porous medium is 5PPI-10PPI, the pore density of the second porous medium is less than 5PPI, and the pore density of the third porous medium is greater than 20PPI.

[0016] In some embodiments, at least one of the first porous medium, the second porous medium, and the third porous medium is silicon carbide in a foam structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of an air-graded porous medium combustion device according to an embodiment of the present utility model.

[0018] Air-staged porous media combustion device 100;

[0019] Shell 1; chamber 11; first chamber 111; second chamber 112; third chamber 113; air inlet 12; air outlet 13; outer shell 14; insulation layer 15; flange 16;

[0020] First porous medium 2;

[0021] Second porous medium 3;

[0022] A third porous medium 4;

[0023] Inlet pipe 5; first orifice plate 6; second orifice plate 7. DETAILED DESCRIPTION

[0024] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0025] The following describes an air-staged porous media combustion device 100 according to an embodiment of the present invention with reference to the accompanying drawings.

[0026] like Figure 1 As shown, the air-staged porous medium combustion device 100 according to an embodiment of the present invention includes a housing 1 , a first porous medium 2 , a second porous medium 3 , a third porous medium 4 and an air inlet pipe 5 .

[0027] The housing 1 has a chamber 11, an air inlet 12 and an air outlet 13. The air inlet 12 and the air outlet 13 are both connected to the chamber 11 and the air inlet 12 is arranged below the air outlet 13. The air inlet 12 is suitable for introducing mixed gas, and the air outlet 13 is suitable for exhausting smoke. Specifically, Figure 1 As shown, the shell 1 is generally cylindrical and an air outlet 13 and an air inlet 12 are respectively provided at the upper and lower ends of the shell 1. Gas and air can be introduced into the shell 1 through the air inlet 12 and burned in the shell 1. The smoke after combustion can be discharged outside the shell 1 through the air outlet 13.

[0028] The first porous medium 2, the second porous medium 3 and the third porous medium 4 are all arranged in the housing 1 and between the air inlet end 12 and the air outlet end 13. The first porous medium 2, the second porous medium 3 and the third porous medium 4 are arranged in sequence from bottom to top. The pore size of the third porous medium 4 is smaller than that of the first porous medium 2, and the pore size of the first porous medium 2 is smaller than that of the second porous medium 3. Specifically, Figure 1As shown, the first porous medium 2, the second porous medium 3 and the third porous medium 4 are arranged in sequence from bottom to top in the chamber 11. The first porous medium 2 forms a porous medium main combustion zone in the shell 1, and the gas can be burned in the first porous medium 2. The second porous medium 3 forms a porous medium mixing zone in the shell 1. The first-stage combustion products (for example, unburned gas and combustion products) flowing out of the first porous medium 2 are subjected to secondary combustion in the second porous medium 3. The third porous medium 4 forms a porous medium heat storage zone in the shell 1 to preheat the secondary air.

[0029] Because the pore size of the second porous medium 3 is larger than that of the first porous medium 2 and the third porous medium 4 (in other words, the pore density of the second porous medium 3 is smaller than that of the first porous medium 2 and the third porous medium 4), the second porous medium 3 can reduce the flow resistance of the gas flowing out of the first porous medium 2, improve the mixing rate and uniformity of the gas and secondary air, thereby improving the combustion efficiency and stability of the secondary combustion and reducing pollutant emissions. Furthermore, the pore size of the third porous medium 4 is the smallest (in other words, the pore density of the third porous medium 4 is the smallest), which increases the specific surface area of ​​the third porous medium 4, providing more surface area for contact with the gas, significantly improving the gas-solid heat exchange efficiency, enhancing the thermal storage function of the porous medium, and improving the preheating effect of the secondary air. Furthermore, the small pore size can prevent the propagation and backfire of the flame, ensuring the stability of the combustion process.

[0030] One end of the intake pipe 5 passes through the third porous medium 4 and is connected to the second porous medium 3. The other end of the intake pipe 5 is arranged in the outlet end 13, and the outer peripheral surface of the intake pipe 5 is spaced apart from the outlet end 13 so that the smoke can be discharged from the chamber 11 between the intake pipe 5 and the outlet end 13. The intake pipe 5 is suitable for introducing secondary air to provide secondary air for the fuel in the second porous medium 3.

[0031] Specifically, if Figure 1As shown, the air intake pipe 5 is a vertical pipe extending in the up and down directions. The air intake pipe 5 is arranged in the air outlet end 13 and the outer circumference of the air intake pipe 5 and the inner circumference of the air outlet end 13 are spaced apart to form an air outlet cavity. The upper end of the air intake pipe 5 extends out of the air outlet end 13, and the lower end of the air intake pipe 5 passes through the third porous medium 4 and is connected with the upper end of the second porous medium 3, so that the secondary air replenishes the second porous medium 3 through the air intake pipe 5, and the flue gas after combustion in the shell 1 is discharged from the shell 1 through the third porous medium 4 and the air outlet cavity, and the flue gas preheats the secondary air through the air intake pipe 5. The preheated secondary air can make the temperature distribution of the porous medium mixing zone (the second porous medium 3) more uniform and improve the stability of the secondary combustion. Secondly, preheated secondary air can better mix with the combustion products, improving gas uniformity, reducing local overheating and incomplete combustion, and improving combustion stability. Uniform gas distribution can also reduce turbulence, improving combustion stability and efficiency. For ammonia combustion, rapid secondary combustion mixing can reduce fuel-type NOx generation from secondary combustion. Finally, preheated secondary air can reduce temperature gradients in the combustion area, reduce thermal stress on the porous media and burner, and extend the service life of the equipment.

[0032] The air-staged porous medium combustion device 100 of the embodiment of the present invention is provided with a first porous medium 2, a second porous medium 3, a third porous medium 4 and an intake pipe 5. According to different fuel types, air temperatures and expected outlet temperatures, the intake end 12 and the intake pipe 5 are controlled to control the air and secondary air ratio, so that a suitable combustion atmosphere and temperature field distribution are created in the first porous medium 2 and the second porous medium 3, and adaptation to various fuels (for example, ammonia or low calorific value fuels) and working conditions is achieved, thereby improving the applicability of the air-staged porous medium combustion device 100. In addition, the provision of the second porous medium 3 and the third porous medium 4 can improve the uniformity of temperature distribution in the chamber 11, reduce the temperature of the main combustion zone and thus reduce pollutant emissions. Through the reverse nested structure of the third porous medium 4 and the intake pipe 5, stable and efficient heat exchange between the secondary air and the combustion flue gas can be achieved, the uneven temperature distribution caused by secondary combustion in the second porous medium 3 is improved, and the risk of material failure caused by radial temperature distribution is reduced.

[0033] In some embodiments, the chamber 11 is divided into a first chamber 111, a second chamber 112, and a third chamber 113 along the vertical direction. The first chamber 111 is located below the second chamber 112, and the second chamber 112 is located below the third chamber 113. The first porous medium 2, the second porous medium 3, and the third porous medium 4 are all arranged in the second chamber 112. Specifically, Figure 1As shown, the first chamber 111, the second chamber 112 and the third chamber 113 are all arranged in sequence from bottom to top, and the first chamber 111 is arranged above the second chamber 112, and the third chamber 113 is arranged above the second chamber 112. The first porous medium 2, the second porous medium 3 and the third porous medium 4 are arranged in the second chamber 112. The fuel gas and the primary air flow into the first chamber 111 through the air inlet end 12, and after mixing in the first chamber 111, flow into the second chamber 112 and are fully burned in the second chamber 112, and then flow out of the chamber 11 through the third chamber 113, thereby reasonably utilizing the effective space of the chamber 11 and making the arrangement of the chamber 11 more reasonable.

[0034] In some embodiments, the inner circumference of the first cavity 111 gradually increases from bottom to top, and the air inlet end 12 is connected to the first cavity 111, and / or the inner circumference of the third cavity 113 gradually decreases from bottom to top, and the air outlet end 13 is connected to the third cavity 113. Specifically, Figure 1 As shown, the first cavity 111 can be a truncated cone cavity with a cross section that gradually increases from bottom to top, the second cavity 112 is a cylindrical cavity with a constant cross section from bottom to top, and the third cavity 113 is a truncated cone cavity with a cross section that gradually decreases from bottom to top. Therefore, the first cavity 111 helps to evenly distribute the gas and air, prevents pressure loss caused by sudden expansion or contraction when the gas enters the chamber 11, reduces local pressure differences in the gas, and ensures uniformity of subsequent processing. The third cavity 113 helps to concentrate the smoke generated after combustion and discharge it from the shell 1 to reduce residue, thereby making the settings of the first cavity 111 and the third cavity 113 more reasonable.

[0035] In some embodiments, the housing 1 includes an outer shell 14 and an insulation layer 15. The insulation layer 15 is provided in the outer shell 14 and is used to keep the chamber 11 warm. Figure 1 As shown, the shell 1 is a metal shell, the insulation layer 15 is a non-metallic insulation layer, and the insulation layer 15 is arranged in the metal shell. The inner circumference of the insulation layer 15 defines a chamber 11. The insulation layer 15 is used to insulate the chamber 11, reduce heat loss, and improve combustion efficiency and thermal energy utilization.

[0036] In some embodiments, the air-staged porous media combustion device 100 further includes a first perforated plate 6 and a second perforated plate 7 .

[0037] The first orifice plate 6 is provided in the chamber 11 and is located below the first porous medium 2, and the second orifice plate 7 is provided in the chamber 11 and is located above the third porous medium 4. Specifically, Figure 1As shown, the first orifice plate 6 and the second orifice plate 7 are both arranged in the second cavity 112, and the first porous medium 2 is installed on the first orifice plate 6, so that the first orifice plate 6 provides an installation basis for the first porous medium 2 to prevent the first porous medium 2 from deforming or shifting under high temperature and high pressure environment. The gas in the first cavity 111 can be evenly distributed into the second cavity 112 through the first orifice plate 6 to ensure uniform distribution of the gas in the second porous medium 3. The second orifice plate 7 is arranged in the second cavity 112 and is located above the third cavity 113. The second orifice plate 7 plays a fixing role on the top of the third porous medium 4 to prevent the third porous medium 4 from deforming or shifting under high temperature and high pressure environment. Therefore, the first orifice plate 6 and the second orifice plate 7 play a fixing role on the first porous medium 2, the second porous medium 3 and the third porous medium 4, providing an installation basis for the first porous medium 2, the second porous medium 3 and the third porous medium 4.

[0038] In some embodiments, both the first orifice plate 6 and the second orifice plate 7 are honeycomb porous plates. Figure 1 As shown, the first orifice plate 6 and the second orifice plate 7 can both adopt a ceramic structure mainly composed of alumina and the first orifice plate 6 and the second orifice plate 7 are both honeycomb porous plates. As a result, the fuel gas can flow evenly into the first porous medium 2 through the first orifice plate 6, and the smoke can flow into the third chamber 113 through the second orifice plate 7.

[0039] In some embodiments, the aperture of the first orifice plate 6 is less than 1 mm, thereby preventing the flame in the second cavity 112 from flowing into the first cavity 111, thereby improving the safety of the gas during the combustion process.

[0040] In some embodiments, the inner circumferential surface of the housing 1 is provided with a flange 16 extending along its circumference, and the lower end of the first porous medium 2 abuts against the upper end of the flange 16 so that the first porous medium 2 is installed in the housing 1. Specifically, Figure 1 As shown, a flange 16 is provided at the lower end of the second cavity 112 , and the first orifice plate 6 is provided on the flange 16 , thereby providing a mounting base for the first orifice plate 6 .

[0041] In some embodiments, the pore density of the first porous medium 2 is 5PPI-10PPI, the pore density of the second porous medium 3 is less than 5PPI, and the pore density of the third porous medium 4 is greater than 20PPI. Figure 1 As shown, the first porous medium 2 has a moderate pore density, typically 5 to 10 PPI, to achieve the highest combustion stability enhancement effect. The second porous medium 3 has a larger pore density, typically 5 PPI or less, to reduce flow resistance and improve mixing rate and uniformity. The third porous medium 4 has a lower pore density, typically 20 PPI or above, which can significantly improve gas-solid heat exchange efficiency, enhance the thermal storage function of the porous medium, and improve the preheating effect of the secondary air.

[0042] In some embodiments, at least one of the first porous medium 2, the second porous medium 3, and the third porous medium 4 is silicon carbide with a foam structure. Specifically, the first porous medium 2, the second porous medium 3, and the third porous medium 4 can all be composed of silicon carbide ceramic material. Since silicon carbide has high thermal conductivity and thermal shock resistance, and is an excellent material for foam structure ceramics used for combustion, the foam structure has a higher specific surface area and heat exchange efficiency, which is conducive to enhancing combustion stability and combustion rate. Therefore, the silicon carbide with a foam structure can significantly improve the combustion efficiency and thermal energy utilization rate of the air-staged porous medium combustion device 100, while ensuring the safety and economy of the air-staged porous medium combustion device 100 and the service life of the air-staged porous medium combustion device 100.

[0043] The following specifically describes the air-graded porous medium combustion device 100 of the embodiment of the present invention. Figure 1 As shown, the air-staged porous media combustion device 100 distributes gas through an external burner gas interface. The external burner gas interface can be divided into an air inlet 12, an air inlet pipe 5, and an air outlet 13. The air inlet 12 is responsible for introducing the fuel and air mixture for primary combustion in the first porous medium 2, and the air inlet pipe 5 is responsible for introducing air for mixing with the primary combustion products and any unburned fuel in the second porous medium 3 or for secondary combustion. The air outlet 13 is connected to the downstream device of the burner to output the combustion flue gas.

[0044] To optimize the spatial temperature distribution within the cylindrical porous media combustion chamber, a premixing chamber 11 is designed between the first chambers 111 to alter the airflow flowing into the burner. The gas and air within the first chamber 111 enter the first porous media 2 through the first orifice plate, where the initial combustion occurs within the first porous media 2 at the lower portion of the combustion zone.

[0045] In order to achieve control over the combustion atmosphere and temperature field distribution, improve combustion stability and reduce pollutant emissions, the burner adopts an air staging strategy based on porous medium combustion. The air inlet pipe 5 cooperates with the third porous medium 4 and the second orifice plate 7. The secondary air enters the second porous medium 3 after preheating and mixes with the high-temperature flue gas produced by the combustion. The second porous medium 3 has a relatively small pore density and is designed to be 5PPI or lower. This larger pore diameter can increase the gas mixing rate and uniformity, and improve the uniformity of secondary combustion in the porous medium. This design method in which secondary combustion and primary combustion are carried out in a porous medium in close contact realizes a compact staged combustion design.

[0046] Air-staged porous media combustion requires reducing the temperature gradient within the burner to ensure long-term stable burner operation. The air outlet 13 is nested with the air inlet pipe 5 and arranged above the second orifice plate 7. The secondary air's full contact with the outlet flue gas and the third porous media 4 promotes heat exchange. The preheated secondary air reduces the radial temperature gradient of the second porous media 3 during the mixing process, thereby reducing radial thermal stress within the porous media.

[0047] In order to improve combustion stability and reduce pollutant emissions, a porous medium combustion method is adopted in the combustion chamber. The first orifice plate 6 is used to achieve a certain amount of first-stage unburned gas preheating and rectification, and a specific porous medium structure is used to maintain combustion in the first porous medium 2, the second porous medium 3, and the third porous medium 4. The first porous medium 2 is used for first-stage combustion, the second porous medium 3 is used for secondary air mixing and secondary combustion, and the third porous medium 4 is used to preheat the secondary air and realize heat storage function in possible operating conditions. The first orifice plate 6 and the second orifice plate 7 adopt a honeycomb porous plate structure. The first orifice plate 6 has a smaller mesh size (pore size less than 1mm) to prevent the flame from propagating upstream, while the second orifice plate 7 can adopt a higher mesh size. The first orifice plate 6 and the second orifice plate 7 adopt a ceramic structure mainly composed of aluminum oxide because the temperature distribution of these two structures is more uniform and the thermal performance requirements are lower. Their purpose is to be used together to fix and limit the position of the first porous medium 2, the second porous medium 3, and the third porous medium 4 in the metal burner shell 1.

[0048] The first porous medium 2, the second porous medium 3 and the third porous medium 4 are all composed of silicon carbide material ceramics with a foam structure. Silicon carbide material has relatively high thermal conductivity and higher thermal shock resistance. It is an excellent material for foam structure ceramics used for combustion. The foam structure has a higher specific surface area and heat exchange efficiency, which is beneficial to enhancing combustion stability and combustion rate. The first porous medium 2 has a moderate pore density, usually 10PPI to 5PPI, to achieve the highest combustion stability enhancement effect. The second porous medium 3 has a lower pore density, usually 5PPI and below, to reduce flow resistance and increase mixing rate and uniformity. The third porous medium 4 has a higher pore density, usually 20PPI and above. Such a structure can significantly improve the gas-solid heat exchange efficiency, enhance the heat storage effect of the porous medium, and improve the preheating effect of the secondary air.

[0049] The air-graded porous media combustion device 100 has the characteristics of adaptability to different fuels and a wide load range. It can be used for the combustion of fuels with load fluctuation characteristics in industrial processes and the combustion of new special fuels, such as low-calorific value hydrogen-rich fuels with large fluctuations or ammonia and ammonia-containing fuel gases such as hydrogen, ammonia, etc., or biomass fuel gases such as methanol and ethanol.

[0050] In summary, the present invention aims to meet the demand for achieving efficient and low-pollution combustion in industrial processes, and proposes an air-graded porous medium combustion device 100, which uses a porous structure made of silicon carbide or alumina ceramic material as a stabilizing medium for the combustion reaction, and utilizes the advantages of porous ceramics such as high heat exchange efficiency, good heat transfer performance, and strong heat storage capacity to improve the reaction rate and stability of fuel combustion. At the same time, combined with the air staging strategy, the combustion state is controlled according to the characteristics of different fuels, so as to achieve efficient and low-pollution utilization of multiple fuels under a wide load variation range.

[0051] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0052] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0053] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0054] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0055] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0056] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An air-staged porous media combustion device, characterized in that: The invention comprises: a shell having a chamber, an air inlet end and an air outlet end, the air inlet end and the air outlet end are both communicated with the chamber and the air inlet end is arranged below the air outlet end, the air inlet end is suitable for introducing mixed gas, and the air outlet end is suitable for exhausting smoke; a first porous medium, a second porous medium and a third porous medium, the first porous medium, the second porous medium and the third porous medium are all arranged in the shell and located between the air inlet end and the air outlet end, the first porous medium, the second porous medium and the third porous medium are arranged from bottom to top in accordance with The third porous medium is set up again, the pore size of the third porous medium is smaller than the pore size of the first porous medium, and the pore size of the first porous medium is smaller than the pore size of the second porous medium; an air inlet pipe, one end of the air inlet pipe passes through the third porous medium and is connected with the second porous medium, the other end of the air inlet pipe is arranged in the air outlet end, and the outer peripheral surface of the air inlet pipe is spaced apart from the air outlet end so that the flue gas is discharged from the chamber between the air inlet pipe and the air outlet end, and the air inlet pipe is suitable for introducing secondary air to provide secondary air for the fuel in the second porous medium.

2. The air-staged porous media combustion device according to claim 1, characterized in that: The chamber is divided into a first chamber, a second chamber and a third chamber along the up and down direction. The first chamber is located below the second chamber, the second chamber is located below the third chamber, and the first porous medium, the second porous medium and the third porous medium are all arranged in the second chamber.

3. The air-staged porous media combustion device according to claim 2, characterized in that: The inner circumference of the first cavity gradually increases from bottom to top, and the air inlet end is communicated with the first cavity, and / or the inner circumference of the third cavity gradually decreases from bottom to top, and the air outlet end is communicated with the third cavity.

4. The air-staged porous media combustion device according to claim 1, characterized in that: The shell comprises an outer shell and a heat-insulating layer. The heat-insulating layer is arranged in the outer shell and is used to keep the chamber warm.

5. The air-staged porous media combustion device according to claim 1, characterized in that: Also includes: a first orifice plate, the first orifice plate being disposed in the chamber and below the first porous medium; and / or, a second orifice plate, the second orifice plate being disposed in the chamber and above the third porous medium.

6. The air-staged porous media combustion device according to claim 5, characterized in that: Both the first orifice plate and the second orifice plate are honeycomb porous plates.

7. The air-staged porous media combustion device according to claim 5, characterized in that: The aperture of the first orifice plate is less than 1 mm.

8. The air-staged porous media combustion device according to claim 1, characterized in that: The inner circumferential surface of the shell is provided with a flange extending along the circumferential direction thereof, and the lower side of the first porous medium abuts against the upper end of the flange so that the first porous medium is installed in the shell.

9. The air-staged porous media combustion device according to claim 1, characterized in that: The pore density of the first porous medium is 5PPI-10PPI, the pore density of the second porous medium is less than 5PPI, and the pore density of the third porous medium is greater than 20PPI.

10. The air-staged porous media combustion device according to claim 1, characterized in that: At least one of the first porous medium, the second porous medium, and the third porous medium is silicon carbide with a foam structure.

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