Radial grading porous medium combustion device

Abstract

The utility model discloses a radial grading porous medium combustion device which comprises a shell, porous media, a first air inlet pipe and a second air inlet pipe, and the porous media comprise the first porous media, the second porous media and the third porous media. The first porous medium, the second porous medium and the third porous medium are all arranged in the shell, a mounting cavity is formed below the second porous medium, the first porous medium is arranged in the mounting cavity, the third porous medium is arranged above the second porous medium, and the aperture of the first porous medium is larger than that of the second porous medium; the aperture of the second porous medium is larger than that of the third porous medium, and the first air inlet pipe and the second air inlet pipe are arranged below the porous media. The radial grading porous medium combustion device has the advantages of being simple in structure, stable in combustion and the like.

Description

TECHNICAL FIELD

[0001] The utility model relates to waste treatment and energy utilization field, specifically, relate to a radial grading's porous medium combustion device. BACKGROUND

[0002] Porous medium combustion technology has the advantages of strong combustion stability, high combustion rate and low pollutant emission, and has broad application prospects in industrial low heat value waste gas treatment and high efficiency burner design.

[0003] In the related art, low heat value is unstable in the burner, and a stable high temperature heat source is needed to maintain the combustion work, and the unreacted fuel is discharged with the low heat value combustible gas, which not only causes energy loss but also may aggravate greenhouse effect and pollute the environment. SUMMARY

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

[0005] Therefore, the embodiment of the utility model provides a radial grading's porous medium combustion device which guarantees low heat value combustion stability and full low heat value combustion.

[0006] The radial grading's porous medium combustion device according to the utility model embodiment comprises a shell, a porous medium, the porous medium includes first porous medium, second porous medium and third porous medium, the first porous medium, the second porous medium and the third porous medium are all arranged in the shell, the second porous medium is below installation cavity, the first porous medium is arranged in the installation cavity, the third porous medium is arranged above the second porous medium, the pore size of the first porous medium is greater than the pore size of the second porous medium, the pore size of the second porous medium is greater than the pore size of the third porous medium, first air inlet pipe and second air inlet pipe, the first air inlet pipe and the second air inlet pipe are arranged below the porous medium, the first air inlet pipe is communicated with the first porous medium and is suitable for the first fuel, the second air inlet pipe is communicated with the second porous medium and is suitable for the second fuel, the heat value of the first fuel is lower than the heat value of the second fuel, the combustion device has preheating state and combustion state, in the preheating state, the second air inlet pipe is communicated with the second fuel to the porous medium, so that the second fuel burns to preheat the porous medium, in the combustion state, the first air inlet pipe is communicated with the first fuel to the porous medium, so that the first fuel burns in the porous medium.

[0007] The radial grading porous medium combustion device of the embodiment of the utility model, set up porous medium, first air inlet pipe and second air inlet pipe, according to the component and temperature of low calorific value gas, select the second fuel for starting preheating working condition, improve the stability of combustion, and provide stable high-temperature heat source for the first fuel for maintaining combustion work, so that the first fuel burns more fully, and the generation of incomplete combustion products is reduced.

[0008] In some embodiments, the shell has a first cavity, a second cavity and a third cavity in communication with each other, the first cavity is arranged below the second cavity, the second cavity is arranged below the third cavity, the porous medium is arranged in the second cavity, and the first air inlet pipe and the second air inlet pipe are in communication with the first cavity.

[0009] In some embodiments, the first cavity further has a first sub-cavity and a second sub-cavity independent of each other, the first sub-cavity is arranged in the second sub-cavity, the first air inlet pipe is in communication with the first sub-cavity, the second air inlet pipe is in communication with the second sub-cavity, the lower end of the first porous medium is arranged opposite to the first sub-cavity in the up-down direction and is in communication with the first sub-cavity, and the lower end of the second porous medium is arranged opposite to the second sub-cavity in the up-down direction and is in communication with the second sub-cavity.

[0010] In some embodiments, the first air inlet pipe includes a first sub-pipe and a second sub-pipe, at least part of the first sub-pipe is arranged in the first sub-cavity and is in communication with the second cavity, the second sub-pipe is arranged outside the shell and is in communication with the first sub-cavity, the first sub-pipe is used for introducing the first fuel, and the second sub-pipe is used for introducing air.

[0011] In some embodiments, the radial grading porous medium combustion device further includes a plurality of swirl vanes, the plurality of swirl vanes are arranged in the first sub-cavity and are arranged in the circumferential direction of the first sub-pipe.

[0012] In some embodiments, the second air inlet pipe includes a third sub-pipe and a plurality of fourth sub-pipes, the third sub-pipe is arranged outside the shell and is in communication with the second sub-cavity, the plurality of fourth sub-pipes are arranged in the second sub-cavity and are arranged in the circumferential direction of the second sub-cavity, and two ends of the fourth sub-pipe are in communication with the second sub-cavity and the second cavity, respectively.

[0013] 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 for heat preservation of the porous medium.

[0014] In some embodiments, the radial grading porous medium combustion device further includes a hole plate, the hole plate is arranged in the shell and is located above the porous medium.

[0015] In some embodiments, the first porous medium has a pore density of 5 PPI-10 PPI, the second porous medium has a pore density of 10 PPI-15 PPI, and the third porous medium has a pore density greater than 20 PPI.

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

[0017] Figure 1 is a structural schematic diagram of a porous medium combustion according to an embodiment of the present application.

[0018] Figure 2 is a mounting schematic diagram of a swirl vane of a porous medium combustion according to an embodiment of the present application.

[0019] Radially staged porous medium combustion device 100;

[0020] Housing 1; first cavity 11; first sub-cavity 111; second sub-cavity 112; second cavity 12; third cavity 13; outer shell 14; thermal insulation layer 15;

[0021] Porous medium 2; first porous medium 21; second porous medium 22; third porous medium 23;

[0022] First air inlet pipe 3; first sub-pipe 31; second sub-pipe 32;

[0023] Second air inlet pipe 4; third sub-pipe 41; fourth sub-pipe 42;

[0024] Perforated plate 5; swirl vane 5. DETAILED DESCRIPTION

[0025] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0026] A radially staged porous medium combustion device 100 according to an embodiment of the present application is described below with reference to the accompanying drawings.

[0027] As shown in Figures 1-2 , the radially staged porous medium combustion device 100 according to an embodiment of the present application includes a housing 1, a porous medium 2, a first air inlet pipe 3, and a second air inlet pipe 4.

[0028] The porous medium 2 comprises a first porous medium 21, a second porous medium 22 and a third porous medium 23, the first porous medium 21, the second porous medium 22 and the third porous medium 23 are all arranged in the shell 1, the second porous medium 22 is arranged below a mounting cavity, the first porous medium 21 is arranged in the mounting cavity, the third porous medium 23 is arranged above the second porous medium 22, the pore size of the first porous medium 21 is larger than the pore size of the second porous medium 22, and the pore size of the second porous medium 22 is larger than the pore size of the third porous medium 23. Specifically, as shown in Figure 1 the shell 1 is generally cylindrical, the upper and lower ends of the shell 1 are respectively provided with an air outlet, a first air inlet and a second air inlet, the first air inlet and the second air inlet are arranged at the bottom of the shell 1, and the air outlet is arranged at the top of the shell 1. The first air inlet and the second air inlet are arranged in the shell 1, and the fuel gas and the air can be introduced into the shell 1 through the first air inlet and the second air inlet and burned in the shell 1. The flue gas after combustion can be discharged out of the shell 1 through the air outlet, the third porous medium 23 is arranged at the upper end of the second porous medium 22, the middle part of the lower end of the second porous medium 22 is arranged in the mounting cavity, (in other words, the second porous medium 22 can be divided into an upper part and a lower part, the upper part is a cylindrical shape with a constant cross-sectional area, and the lower part is a circular annular column shape, and the inner circumferential surface of the lower part defines the mounting cavity), and the first porous medium 21 is arranged in the mounting cavity.

[0029] The first air inlet pipe 3 and the second air inlet pipe 4 are arranged below the porous medium 2 and communicate with the shell 1, the first air inlet pipe 3 communicates with the first porous medium 21 and is adapted to introduce the first fuel, the second air inlet pipe 4 communicates with the second porous medium 22 and is adapted to introduce the second fuel, the heat value of the first fuel is lower than the heat value of the second fuel, the combustion device has a preheating state and a combustion state, in the preheating state, the second air inlet pipe 4 introduces the second fuel into the porous medium 2, so that the second fuel is burned to preheat the porous medium 2, in the combustion state, the first air inlet pipe 3 introduces the first fuel into the porous medium 2, so that the first fuel is burned in the porous medium 2. Specifically, as shown in Figure 1As shown, the first air inlet pipe 3 and the second air inlet pipe 4 are connected to the first air inlet and the second air inlet, respectively. In the preheating state, the second fuel (e.g., methane) is introduced into the shell 1 through the second air inlet pipe 4, so that the second fuel burns in the shell 1 to preheat the porous medium 2. In the combustion state, the first fuel (e.g., low calorific value gas) is introduced into the shell 1 through the first air inlet pipe 3, so that the first fuel burns in the porous medium 2. The first porous medium 21 adopts a relatively low pore density (i.e., the pore size of the first porous medium 21 is large), which can promote the mixing and diffusion of the first fuel and air to promote combustion. The second porous medium 22 mainly provides a flame stabilization position for the high-power first fuel under combustion conditions. Therefore, a pore density suitable for combustion is adopted to ensure that the second porous medium 22 has both gas-solid heat exchange intensity and flame holding capacity under high flow rate. The third porous medium 23 provides heat storage capacity and thermal stability under high power fluctuation for the burner as a whole, so a higher pore density is adopted (ie, the pore size of the third porous medium 23 is smaller) to achieve sufficient gas-solid heat exchange capacity and strong heat storage capacity.

[0030] Since low calorific value gas itself is difficult to ignite directly, it needs to be preheated to a certain temperature before it can burn stably. The high-temperature flue gas generated by the combustion of the second fuel can quickly preheat the porous medium to its operating temperature. While preheating the porous medium 2, the flue gas from the combustion of the second fuel can also be used to heat the low calorific value gas generator from a cold state to the operating temperature, ensuring that the first fuel is at a suitable temperature when it enters the burner, thereby improving the combustion efficiency of the first fuel. In addition, the calorific value of the first fuel is low, and it may not be able to maintain a stable flame when burned alone. In this case, the second fuel can provide additional heat to ensure that the burner can still operate stably under low calorific value gas conditions, improve the overall thermal energy utilization of the burner, ensure that the low calorific value gas can be fully burned, and reduce unburned gas emissions. Secondly, the second fuel can create a high-temperature environment in the porous medium 2, which helps the decomposition and combustion of the first fuel, further improving the combustion efficiency of the first fuel. Finally, the combustion of the second fuel can quickly generate high-temperature flue gas, achieving rapid startup.

[0031] The radially graded porous medium combustion device 100 of the embodiment of the present invention is provided with a porous medium 2, a first air inlet pipe 3 and a second air inlet pipe 4. According to the composition and temperature of the low calorific value gas, a second fuel is selected for starting the preheating condition. The second fuel flows into the porous medium 2 through the first air inlet pipe 3 to preheat the porous medium 2, thereby improving the stability of the combustion and providing a stable high-temperature heat source for the first fuel to maintain the combustion operation, so that the first fuel burns more fully and reduces the generation of incomplete combustion products. In addition, the use of the porous medium 2 combustion technology can improve the combustion intensity and combustion rate of the low calorific value gas, improve the stability of the gas combustion process, ensure the adaptability to the dynamic changes of the low calorific value workload, and reduce the output fluctuation of the burner.

[0032] In some embodiments, the shell 1 has a first cavity 11, a second cavity 12 and a third cavity 13 which are in communication with each other, the first cavity 11 is arranged below the second cavity 12, the second cavity 12 is arranged below the third cavity 13, the porous medium 2 is arranged in the second cavity 12, and the first air inlet pipe 3 and the second air inlet pipe 4 are both in communication with the first cavity 11. Specifically, as shown in Figure 1 the first cavity 11, the second cavity 12 and the third cavity 13 are sequentially arranged from bottom to top, and the first cavity 11 is arranged above the second cavity 12, the third cavity 13 is arranged above the second cavity 12, the first porous medium 21, the second porous medium 22 and the third porous medium 23 are arranged in the second cavity 12, the first air inlet pipe 3 and the second air inlet pipe 4 are both in communication with the first cavity 11, and the air outlet is formed at the top of the third cavity 13, thereby reasonably utilizing the effective space of the shell 1 and making the shell 1 more reasonable.

[0033] In some embodiments, the first cavity 11 further has a first sub-cavity 111 and a second sub-cavity 112 which are independent of each other, the first sub-cavity 111 is arranged in the second sub-cavity 112, the first air inlet pipe 3 is in communication with the first sub-cavity 111, the second air inlet pipe 4 is in communication with the second sub-cavity 112, the lower end of the first porous medium 21 is arranged in the first sub-cavity 111 in the up-down direction and is in communication with the first sub-cavity 111, and the lower end of the second porous medium 22 is arranged in the second sub-cavity 112 in the up-down direction and is in communication with the second sub-cavity 112. Specifically, as shown in Figure 1 the shell 1 further includes a mounting cylinder which is arranged in the first cavity 11 to divide the mounting cylinder into the first sub-cavity 111 and the second sub-cavity 112, the first sub-cavity 111 is formed on the inner circumferential surface of the mounting cylinder, the second sub-cavity 112 is formed between the outer circumferential surface of the mounting cylinder and the inner circumferential surface of the first cavity 11, the first air inlet pipe 3 is in communication with the first sub-cavity 111 to make the first fuel flow into the first sub-cavity 111 through the first air inlet pipe 3, the second air inlet pipe 4 is in communication with the second sub-cavity 112 to make the second fuel flow into the second sub-cavity 112 through the second air inlet pipe 4, and the lower end surface of the first porous medium 21 is arranged in the first sub-cavity 111 in the up-down direction, and the second porous medium 22 is arranged in the second sub-cavity 112 in the up-down direction, in the preheating state, the second fuel in the second sub-cavity 111 flows into the second porous medium 22, so that the second fuel burns in the second porous medium 22 to preheat the porous medium 2, and in the combustion state, the first fuel in the first sub-cavity 111 flows into the first porous medium 21, and the first fuel burns in the first porous medium 21.

[0034] In some embodiments, the first air inlet pipe 3 comprises a first sub-pipe 31 and a second sub-pipe 32, the first sub-pipe 31 is at least partially arranged in the first sub-cavity 111 and communicates with the second cavity 12, the second sub-pipe 32 is arranged outside the shell 1 and communicates with the first sub-cavity 111, the first sub-pipe 31 is used to introduce the first fuel, and the second sub-pipe 32 is used to introduce air. Specifically, as shown in Figure 1 the first sub-pipe 31 is an L-shaped pipe, the inlet of the first sub-pipe 31 extends out of the first sub-cavity 111 and can introduce the first fuel, the outlet of the first sub-pipe 31 is arranged in the first sub-cavity 111 and opposite to the first porous medium 21, and the second sub-pipe 32 is arranged at the lower end of the shell 1 and communicates with the upper end of the second sub-pipe 32 and the first sub-cavity 111, thereby the first fuel is transported into the first porous medium 21 through the first sub-pipe 31, and the air is transported into the first sub-cavity 111 through the second sub-pipe 32, so that the first fuel is combusted in the first porous medium 21.

[0035] In some embodiments, the radially staged porous medium combustion device 100 further comprises a plurality of swirl vanes 5, the plurality of swirl vanes 5 are arranged in the first sub-cavity 111 and are spaced apart around the circumference of the first sub-pipe 31. Specifically, as shown in Figure 2 the plurality of swirl vanes 5 each helically extend around the circumference of the first sub-pipe 31 from top to bottom, the plurality of swirl vanes 5 are each arranged in the first sub-cavity 111 and are equally spaced apart around the circumference of the first sub-pipe 31, thereby the air flows into the first sub-cavity 111 in a swirling manner, reduces the local flow rate of the air, and creates a central recirculation zone so that the first fuel produces a swirling flame, which improves the combustion stability of the first fuel.

[0036] In some embodiments, the second air inlet pipe 4 comprises a third sub-pipe 41 and a plurality of fourth sub-pipes 42, the third sub-pipe 41 is arranged outside the shell 1 and communicates with the second sub-cavity 112, and the plurality of fourth sub-pipes 42 are arranged in the second sub-cavity 112 and are spaced apart around the circumference of the second sub-cavity 112, and the two ends of the fourth sub-pipe 42 respectively communicate with the second sub-cavity 112 and the second cavity 12. Specifically, as shown in Figure 1 and Figure 2 the third sub-pipe 41 is a horizontal pipe and is arranged outside the shell 1, the outlet of the third sub-pipe 41 communicates with the second sub-cavity 112, and the plurality of fourth sub-pipes 42 are vertical pipes and are equally spaced apart around the circumference of the second sub-cavity 112, the upper end of the fourth sub-pipe 42 communicates with the second cavity 12, and the lower end of the second cavity 12 communicates with the second sub-cavity 112, thereby the mixture of the second fuel and the combustion air flows into the second sub-cavity 112 through the third sub-pipe 41 and flows into the second cavity 12 through the plurality of fourth sub-pipes 42, which improves the uniformity of the mixing and flow of the second fuel and the air, prevents the second fuel from directly passing through the perforated plate 5 into the porous medium 2 region, prolongs the mixing time of the second fuel and the air, prevents the second fuel from flowing short, and improves the uniformity of the distribution of the second fuel in the second porous medium.

[0037] In some embodiments, the shell 1 comprises an outer shell 14 and a thermal insulation layer 15, the thermal insulation layer 15 is arranged in the outer shell 14, and the thermal insulation layer 15 is used to insulate the porous medium 2. Specifically, as shown in Figure 1 the outer shell 14 is a metal shell, the thermal insulation layer 15 is a non-metallic thermal insulation layer, and the thermal insulation layer 15 is arranged in the metal shell, and the thermal insulation layer 15 is used to insulate the porous medium 2, reduce heat loss, and improve combustion efficiency and thermal energy utilization.

[0038] In some embodiments, the radially staged porous medium combustion device 100 further comprises a hole plate 5 arranged in the shell 1 and above the porous medium 2. Specifically, as shown in Figure 1 the hole plate 5 is arranged in the second cavity 12, and the porous medium 2 is mounted on the hole plate 5, so that the hole plate 5 provides a mounting basis for the porous medium 2 and prevents the porous medium 2 from deforming or shifting under high temperature and high pressure environment.

[0039] In some embodiments, the hole plate 5 is a honeycomb hole plate 5. Specifically, as shown in Figure 1 the hole plate 5 can adopt a ceramic structure mainly composed of alumina, and all the hole plates 5 are honeycomb hole plates 5, so that the gas can uniformly flow out of the porous medium 2 through the hole plate 5.

[0040] In some embodiments, the first porous medium 21 has a hole density of 5PPI-10PPI, the second porous medium 22 has a hole density of 10PPI-15PPI, and the third porous medium 23 has a hole density greater than 20PPI. Specifically, as shown in Figure 1 5PPI-10PPI of the first porous medium 21 can make the first fuel burn at low calorific value, and provide stable combustion for higher calorific value working conditions. The hole density of the second porous medium 22 is 10PPI-15PPI, which can improve the preheating and heat reflux efficiency, and also has the effect of combustion enhancement of accommodating flame surface. The hole density of the third porous medium 23 is greater than 20PPI or above, which can significantly improve the gas-solid heat exchange efficiency to enhance the heat storage effect of the porous medium 2.

[0041] In some embodiments, at least one of the first porous medium 21, the second porous medium 22, and the third porous medium 23 is silicon carbide with a foam structure. Specifically, the first porous medium 21, the second porous medium 22, and the third porous medium 23 can all be composed of silicon carbide ceramic material. Since silicon carbide has high thermal conductivity and thermal shock resistance, and silicon carbide is an excellent material for foam structure ceramics used for combustion, the foam structure has a higher specific surface area and heat transfer 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 radially graded porous medium combustion device 100, while ensuring the safety and economy of the radially graded porous medium combustion device 100.

[0042] like Figures 1-2 As shown, according to the radially graded porous medium combustion device 100 of the embodiment of the utility model, the low calorific value gas combustion device is connected to the low calorific value gas and the auxiliary fuel through the external burner gas interface. In order to adapt to the combustion requirements of gases with different calorific values. The porous medium 2 burner for low calorific value gas combustion needs to be started and preheated. At this time, the second air inlet pipe 4 is responsible for introducing premixed air and methane to perform high-power start-up preheating combustion. While preheating the porous medium 2 blocks, the combustion flue gas is used to heat the low calorific value gas generator from a cold state to the working temperature. The second sub-tube 42 and the first sub-tube 41 are responsible for introducing air and low calorific value fuel gas to perform low calorific value gas swirl combustion. The combustion flue gas can be used for subsequent further heat exchange utilization; the burner flue gas outlet is connected to the heat exchanger used to heat the fuel cell stack and outputs high-temperature flue gas. This combustion arrangement not only enables the start-up of burners using methane fuel and the stable operation of burners processing low calorific value gases, but also allows the use of methane for supplementary combustion during the combustion of ultra-low calorific value fuels, thereby achieving stable operation of burners operating under small amounts of ultra-low calorific value gases.

[0043] In order to adapt to different low calorific value gas sources with large differences in calorific value loads, two combustion organization modes are adopted inside the burner: swirl combustion and premixed combustion.

[0044] The second sub-tube 42 enters the swirl blade 5 and, together with the first sub-tube 41 and the hollow, annular preheating zone of the porous medium 2 (the porous medium 2 preheating zone comprises the lower portion of the second porous medium 22 and the shell 1), forms a low-calorific-value gas swirl combustion zone. For low-calorific-value gas, an air swirl combustion method is used to create a central recirculation zone, reducing the local air velocity and thus improving the combustion stability of the low-calorific-value gas.

[0045] The third sub-tube 31 passes through the fourth sub-tube 32 to the outside of the annular porous medium 2 preheating area to form a circumferentially distributed premixed combustion structure. For high-power methane combustion, the premixed combustion method can maintain stable flame inside the burner while reducing local high-temperature areas and reducing combustion pollutant emissions. Through the structural design of the premixed ring tube, the mixing and flow time of the mixed gas before entering the preheating area of the porous medium 2 can be improved, the uniformity of the mixed flow can be improved, the risk of backfire at low flow rate can be reduced, and the mixed gas can be prevented from flowing short-circuit and having poor component distribution, thereby avoiding the occurrence of local backfire to cause combustion in the chamber upstream of the porous medium 2, and damaging the burner.

[0046] In order to improve the combustion stability and reduce pollutant emissions, a porous medium 2 combustion method is used in the combustion chamber. The porous medium 2 combustion chamber can be divided into a non-metallic insulation layer, a porous medium 2 preheating area, a porous medium 2 center pre-combustion area (the porous medium 2 center pre-combustion area is the area where the first porous medium 21 is located), a porous medium 2 main combustion area (the porous medium 2 main combustion area is the area where the upper part of the second porous medium 22 is located), a porous medium 2 heat storage area (the porous medium 2 heat storage area is the area where the third porous medium 23 is located), and a porous medium 2 fixed area (the porous medium 2 fixed area is the area where the hole plate 5 is located). The porous medium 2 combustion chamber is arranged above the combustion head structure, and has a foamed porous structure of silicon carbide material. The silicon carbide material has relatively high thermal conductivity and higher thermal shock resistance, is an excellent material for realizing the foamed structure, and has higher specific surface area and heat exchange efficiency, which is beneficial to strengthening the combustion stability and combustion rate, and is a high-efficiency structure for porous medium 2 combustion. The non-metallic insulation layer and the porous medium 2 fixed area are made of ceramic material mainly containing alumina, which has relatively low cost and sufficient heat preservation and fixing capacity. The fixed area adopts a honeycomb structure to reduce flow resistance and ensure the limiting capacity.

[0047] The porous medium 2 preheating area has an annular structure, and the center pre-combustion area is arranged in the middle. The preheating area mainly performs preheating and partial combustion of the methane / air mixed gas. Because the flow rate of the mixed gas is relatively high, the flame is usually distributed in the more downstream main combustion area, and therefore the preheating area usually has a small number of flame surfaces, thereby assisting the main burner to return heat and preheat the unburned mixed gas. A relatively high pore density of 10-15 PPI is usually adopted to improve the preheating and heat return efficiency, and the combustion enhancement effect of accommodating the flame surface is also achieved.

[0048] The central pre-combustion zone of the porous medium 2 is located downstream of the swirl combustion structure, mainly for low-calorific value gas combustion, and the root of the low-calorific value gas swirl flame is located in the cavity between the central pre-combustion zone and the swirl combustion structure, which provides combustion stability for higher-calorific value conditions, and the upper part enters the central pre-combustion zone for combustion, and the central pre-combustion zone cooperates with the preheating zone to form a downstream heat accumulator, so that the low-calorific value gas can react in the high-temperature region of the porous medium 2 in a low-calorific value state. The central pre-combustion zone usually adopts a relatively low hole density of 5-10 PPI, thereby promoting the mixing and diffusion of low-calorific value gas and air and promoting combustion.

[0049] The main combustion zone of the porous medium 2 mainly provides a flame stable position for high-power methane combustion conditions, and therefore adopts a hole density suitable for combustion, 5-10 PPI, which has both gas-solid heat exchange strength and flame containment capacity under high flow rate. The heat storage zone of the porous medium 2 provides heat storage capacity and thermal stability under large power fluctuation for the burner as a whole, and therefore adopts a higher hole density of 20 PPI and above to achieve sufficient gas-solid heat exchange capacity and strong heat storage capacity.

[0050] For general low-calorific value gas combustion conditions, the flame is maintained in the central pre-combustion zone of the porous medium 2, and for ultra-low-calorific value gas treatment, a certain afterburning is usually required to maintain the heat balance of the burner as a whole, at which time methane / air combustion is simultaneously performed, and the flame is distributed in the central pre-combustion zone of the porous medium 2 and the main combustion zone of the porous medium 2.

[0051] As shown in Figure 2 The cross-sectional view of the swirl premixed combustion head is shown in FIG. 1, in order to improve the uniformity of temperature distribution, the swirl combustion structure is arranged in the lower central part of the metal burner shell 14, and the premixed combustion pipe is arranged around the lower part of the metal burner shell 14.

[0052] The radial staged porous medium combustion device 100 has the characteristics of being capable of simultaneously adapting to high-power high-calorific value gas and low-power low-calorific value gas combustion, and can be used for industrial low-calorific value gas treatment or combustion with load fluctuation characteristics. In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0053] In addition, the terms "first", "second", "third", etc. are used herein only to describe different instances, and are not used to indicate or imply relative importance or a number of indicated technical features. Thus, features defined with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0054] In the present application, unless otherwise specifically defined and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected or in communication with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0055] In the present application, unless otherwise specifically defined and limited, the first feature is "on" or "under" the second feature. The first and second features can be in direct contact, or the first and second features can be in indirect contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0056] In the present application, 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 application. In the description, the illustrative representation of the above terms is not necessarily directed to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics 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 the present application and the features of different embodiments or examples without contradiction.

[0057] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and modifications to the above embodiments within the scope of the present application.

Claims

1. A radially graded porous media combustion device, characterized in that: include: case; The porous medium includes 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. A mounting cavity is provided below the second porous medium. The first porous medium is arranged in the mounting cavity. The third porous medium is arranged above the second porous medium. The pore size of the first porous medium is larger than that of the second porous medium. The pore size of the second porous medium is larger than that of the third porous medium. The first air inlet pipe and the second air inlet pipe are arranged in the housing. Below the porous medium, the first air inlet pipe is connected to the first porous medium and is suitable for passing a first fuel, the second air inlet pipe is connected to the second porous medium and is suitable for passing a second fuel, the calorific value of the first fuel is lower than the calorific value of the second fuel, and the combustion device has a preheating state and a combustion state. In the preheating state, the second air inlet pipe passes the second fuel into the porous medium so that the second fuel burns to preheat the porous medium. In the combustion state, the first air inlet pipe passes the first fuel into the porous medium so that the first fuel burns in the porous medium.

2. The radially graded porous media combustion device according to claim 1, characterized in that: The shell has a first cavity, a second cavity and a third cavity that are interconnected. The first cavity is arranged below the second cavity, and the second cavity is arranged below the third cavity. The porous medium is arranged in the second cavity, and the first air inlet pipe and the second air inlet pipe are both connected to the first cavity.

3. The radially graded porous media combustion device according to claim 2, characterized in that: The first cavity further has a first sub-cavity and a second sub-cavity that are independent of each other. The first sub-cavity is arranged in the second sub-cavity. The first air inlet pipe is connected to the first sub-cavity, and the second air inlet pipe is connected to the second sub-cavity. The lower end of the first porous medium is arranged opposite to the first sub-cavity in the vertical direction and is connected to the first sub-cavity. The lower end of the second porous medium is arranged opposite to the second sub-cavity in the vertical direction and is connected to the second sub-cavity.

4. The radially graded porous media combustion device according to claim 3, characterized in that: The first air intake pipe includes a first sub-pipe and a second sub-pipe, at least a portion of the first sub-pipe is arranged in the first sub-cavity and is connected to the second cavity, the second sub-pipe is arranged outside the shell and is connected to the first sub-cavity, the first sub-pipe is used to introduce the first fuel, and the second sub-pipe is used to introduce air.

5. The radially graded porous media combustion device according to claim 4, characterized in that: The radially graded porous media combustion device further includes a plurality of swirl blades, which are arranged in the first sub-cavity and spaced apart around the circumference of the first sub-tube.

6. The radially graded porous media combustion device according to claim 3, characterized in that: The second air inlet pipe includes a third sub-pipe and multiple fourth sub-pipes, the third sub-pipe is arranged outside the shell and is connected to the second sub-cavity, the multiple fourth sub-pipes are arranged in the second sub-cavity and are spaced apart along the circumference of the second sub-cavity, and the two ends of the fourth sub-pipe are respectively connected to the second sub-cavity and the second cavity.

7. The radially graded 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 porous medium warm.

8. The radially graded porous media combustion device according to claim 1, characterized in that: The invention also includes a perforated plate, which is arranged in the shell and above the porous medium.

9. The radially graded 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 10PPI-15PPI, and the pore density of the third porous medium is greater than 20PPI.

10. The radially graded 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.

Images