A porous ceramic burner head for low nitrogen burner

Abstract

The present invention discloses a porous ceramic burner head for a low-nitrogen burner, comprising a burner head shell and an inner air cylinder; a fire hole plate is provided at the top opening of the burner head shell, the fire hole plate comprises at least two porous medium ceramic plates, each porous medium ceramic plate is provided with an inner protective plate with holes on the inner side; the inner air cylinder is inserted into the burner head shell, and a plurality of vents are provided on the surface of the inner air cylinder. The burner head of the present invention has high combustion efficiency and low CO and NOx emissions; it has a dual anti-flashback protection function and reliable safety performance; it can achieve uniform distribution of airflow, promote uniform premixing of fuel, and stabilize combustion conditions.

Description

Technical Field

[0001] The invention relates to the technical field of gas burners, and in particular to a porous ceramic burner head for a low-nitrogen burner. Background Art

[0002] At present, the heat load of vertical heating furnaces on the market is mainly below 1MW, and most of them are equipped with simple partially premixed gas burners. When in use, it is necessary to manually adjust the gas valve and air distribution mechanism, and manually adjust the air-fuel ratio. Fuel often burns under unreasonable excess air coefficient, incomplete combustion or excessive exhaust temperature, and the fuel is not used reasonably, which wastes energy on the one hand, and on the other hand, due to the structural size of the heating furnace and the fact that most of the simple partially premixed burners are induced structures, the primary air supply is insufficient, the secondary air supply is uneven, the flame is long, the flue gas flow rate is fast, the residence time in the furnace is short, and the amount of pollutants generated is large.

[0003] With the increasing prominence of environmental issues, the formulation of relevant gas fuel combustion equipment standards at home and abroad, and the implementation of nitrogen oxide control measures by government environmental protection departments, more and more low-nitrogen combustion technologies are also applied to the field of combustion technology. The nitrogen reduction methods used by low-nitrogen burners on the market currently include flue gas recirculation technology and full premixed combustion technology. Flue gas recirculation technology is mainly used in larger gas boilers, while small gas heating furnaces mainly use full premixed combustion technology. Full premixed combustion refers to the full mixing of gas and all required air before the fire hole of the burner, and then rapid and complete combustion after the fire hole. Full premixed combustion has a fast combustion speed, complete combustion, and the overall flame temperature is lower than the inner flame temperature of partial premixed combustion, and nitrogen oxide emissions are low. At present, most of the fully premixed burners at home and abroad are flat and cylindrical. Among them, the fire hole media of flat-plate burners are mostly metal fiber materials and porous ceramic plate materials. In actual applications, the former is expensive. If there is local blockage, it may be damaged by oxidation and corrosion when used in high temperature environment for a long time. The latter has low hardness and is easy to break. If damaged, there may be a risk of flashback. Therefore, the widespread application of both is subject to certain limitations. Summary of the invention

[0004] The purpose of the present invention is to provide a porous ceramic burner head for a fully premixed low-nitrogen burner using natural gas as fuel, with high combustion efficiency and low nitrogen emissions, so as to solve the technical problems existing in the existing flat-plate burners using porous ceramic plates as fire hole media.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows.

[0006] A porous ceramic burner head for a low-nitrogen burner comprises a burner head shell and an inner wind tube; a fire hole plate is provided at the top opening of the burner head shell, the fire hole plate comprises at least two porous medium ceramic plates, and an inner protective plate with holes is provided on the inner side of each porous medium ceramic plate; the inner wind tube is inserted into the burner head shell, and a plurality of ventilation holes are provided on the surface of the inner wind tube.

[0007] Furthermore, the combustion head shell 1 is mainly composed of a front end plate 13, an upper plate 14, a lower plate 15 and a rear end plate 16; the inner wind tube 2 is inserted into the combustion head shell 1 from the through hole opened on the front end plate 13, and is sealed and connected to the front end plate 13; at least two openings are opened on the upper plate 14, the internal protective plate 4 is arranged at the opening from the inner side of the upper plate 14, and the porous medium ceramic plate 3 is arranged at the opening from the outer side of the upper plate 14; the rear end plate 16 is provided with one or more sewage discharge holes.

[0008] Furthermore, the upper plate 14 includes two top surfaces at an angle, each of which is provided with one or more openings, one or more porous dielectric ceramic plates 3 are provided on the outside of each opening, and one or more internal protective plates 4 are provided on the inside of each opening.

[0009] Furthermore, a spark guide plate 8 is provided at the edge of the porous medium ceramic plate 3 , and a circular heat dissipation hole or a strip heat dissipation hole is opened on the spark guide plate 8 .

[0010] Furthermore, the spark guide piece 8 includes a first spark guide piece 81 and a second spark guide piece 82, which are respectively located at the top of the two top surfaces.

[0011] Furthermore, the porous dielectric ceramic plate 3 is fixed on the upper plate 14 through a plurality of pressing plates, and the connection between the porous dielectric ceramic plate 3 and the upper plate 14 is sealed with high temperature resistant glue.

[0012] Furthermore, the inner protection plate 4 is densely provided with circular holes and / or strip holes.

[0013] Furthermore, the inner air duct 2 includes an air outlet duct 10 at the front end and a connecting duct 12 at the rear end, the air outlet duct 10 is located inside the combustion head shell 1, the connecting duct 12 is located outside the combustion head shell 1, and a mounting flange 11 is provided at the end of the connecting duct 12. The multiple ventilation openings 17 are closely arranged on the surface of the air outlet duct 10.

[0014] Furthermore, the apertures of the plurality of ventilation openings 17 gradually increase from the front end to the rear end of the inner air cylinder 2 .

[0015] Furthermore, the total opening area of ​​the plurality of ventilation openings 17 is equivalent to the inlet area of ​​the mounting flange 11 .

[0016] It can be seen from the above technical solutions that the embodiments of the present invention have the following advantages:

[0017] The combustion head of the invention has a compact structure, high combustion efficiency and low CO and NOx emissions.

[0018] The burner head of the present invention has a fire hole plate disposed on its fire hole surface, which includes two or more porous medium ceramic plates. The number of porous medium ceramic plates can be adjusted according to the required heat load to reduce the area of ​​a single porous medium ceramic plate, thereby effectively reducing the possibility of the fire hole plate being deformed and broken due to thermal stress caused by the temperature increase. In addition, an internal protective plate is disposed under the porous medium ceramic plate, and the double-layer structure formed together can realize a dual anti-backfire protection function, and the safety performance is more reliable.

[0019] The burner head of the present invention is provided with an internal wind tube, which can realize uniform distribution of airflow under variable load conditions and promote uniform premixing of fuel. The burner of the present invention can realize a combustion mode of completely premixed gas fuel, and the combustion condition is stable.

[0020] As can be seen from the above, the burner head of the present invention has high combustion efficiency and low CO and NOx emissions; it has dual anti-flashback protection functions and reliable safety performance; it can achieve uniform distribution of airflow, promote uniform premixing of fuel, and stable combustion conditions. The burner head of the present invention can be used not only in small and medium-sized industrial heating systems, but also in civil and commercial heating and domestic hot water supply systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments and the description of the prior art will be briefly introduced below. 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 creative work.

[0022] Figure 1 1 is a schematic structural diagram of a porous ceramic burner head for a low nitrogen burner according to an embodiment of the present invention;

[0023] Figure 2 is a schematic structural diagram of a combustion head housing in an embodiment of the present invention;

[0024] Figure 3 It is a structural schematic diagram of an inner air duct in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. 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 creative work should fall within the scope of protection of the present invention.

[0026] The terms "first", "second", "third", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0027] The following is a detailed description through specific embodiments.

[0028] Please refer to Figures 1 to 3 One embodiment of the present invention provides a porous ceramic burner head for a low-nitrogen burner (hereinafter referred to as the burner head).

[0029] The burner head comprises a burner head shell 1 and an inner wind tube 2; a fire hole plate is provided at the top opening of the burner head shell 1, and the fire hole plate comprises at least two porous medium ceramic plates 3, and an internal protective plate 4 is provided on the inner side of each porous medium ceramic plate 3; the inner wind tube 2 is inserted into the burner head shell 1, and a plurality of ventilation holes 17 are provided on the surface of the inner wind tube 2.

[0030] Among them, the fire hole plate can adjust the number of porous medium ceramic plates 3 according to the required heat load, and change the area of ​​a single porous medium ceramic plate. The porous medium ceramic plate 3 and the internal protection plate 4 are both provided with dense through holes to allow gas fuel to pass through. Optionally, the internal protection plate 4 is densely provided with through holes in the form of round holes and / or strip holes, which have an anti-flashback function. Optionally, the width gap of the strip holes is between 0.5-1.5mm, the porosity of the strip holes is between 50%-60%, and the thickness is between 1-8mm; the diameter of the round holes is between 1-2mm, and the porosity is between 40%-60%; the thickness of the internal protection plate 4 is between 3-10mm.

[0031] The combustion head shell 1 is mainly composed of a front end plate 13, an upper plate 14, a lower plate 15 and a rear end plate 16, and has a hollow inner cavity. A through hole is provided on the front end plate, and the inner air tube 2 is inserted into the combustion head shell 1 from the through hole provided on the front end plate 13, and is sealed and connected to the front end plate 13. At least two openings are provided on the upper plate 14 to form a fire hole surface; the internal protective plate 4 is arranged at the opening from the inner side of the upper plate 14, and the porous medium ceramic plate 3 is arranged at the opening from the outer side of the upper plate 14; the internal protective plate 4 and the porous medium ceramic plate 3 together constitute a double-layer fire hole plate. One or more drainage holes, such as 1-3 drainage holes, are provided on the rear end plate 16.

[0032] Optionally, the upper plate 14 includes two top surfaces at an angle, each top surface is provided with one or more openings, the outer side of each opening is provided with one or more porous dielectric ceramic plates 3, and the inner side of each opening is provided with one or more internal protective plates 4.

[0033] Optionally, the porous medium ceramic plate 3 is fixed on the upper plate 14 by a plurality of pressing plates, and the pressing plates may be provided with mounting holes and are mounted on the upper plate 14 by bolts. The pressing plates may include a Z-type pressing plate 5 and a F-type pressing plate 7. The F-type pressing plate 7 is arranged between the two top surfaces, and has two pressing feet respectively used to fix the upper edges of the porous medium ceramic plates 3 arranged on the two top surfaces. The Z-type pressing plates 5 are arranged in a dispersed manner, and are respectively used to fix the lower edge, left edge and edge of the porous medium ceramic plate 3.

[0034] Optionally, the connection between the porous medium ceramic plate 3 and the upper plate 14 is sealed with a high temperature resistant glue to prevent the mixed gas from leaking out from the edge and burning the metal frame of the surrounding combustion head shell. The high temperature resistant glue can be, for example, Shilin SL8081 high temperature resistant sealant.

[0035] Optionally, a spark guide 8 is provided at the edge of the porous medium ceramic plate 3, and the spark guide is used to turbulent flame to stabilize combustion, and circular heat dissipation holes or strip heat dissipation holes and fixing holes for installation and fixing are provided thereon. Further, the spark guide 8 includes a first spark guide 81 and a second spark guide 82, which are respectively located at the top of the two top surfaces; a first spark guide 81 can be provided on both sides of the top of one of the top surfaces, and a second spark guide 82 can be provided on both sides of the top of the other top surface. Optionally, the spark guide 8 can be installed on the Z-shaped pressing plate 5 through the fixed holes provided. Further, the spark guide 8 and the Z-shaped pressing plate 5 can be separated by a heat insulating gasket 6.

[0036] Optionally, the inner air cylinder 2 includes a front air outlet cylinder 10 and a rear connecting cylinder 12, the air outlet cylinder 10 is located inside the combustion head shell 1, the connecting cylinder 12 is located outside the combustion head shell 1, the multiple vents 17 are closely arranged on the surface of the air outlet cylinder 10, and the end of the connecting cylinder 12 is provided with a mounting flange 11. The connecting cylinder 12 and the mounting flange 11, as well as the connecting cylinder 12 and the front end plate 13 of the combustion head shell 1, can be connected by welding.

[0037] Optionally, the apertures of the plurality of ventilation openings 17 gradually increase from the front end to the rear end of the inner air cylinder 2 .

[0038] Optionally, the total opening area of ​​the plurality of ventilation openings 17 is equivalent to the inlet area of ​​the mounting flange 11 .

[0039] As described above, the present invention discloses a porous ceramic burner head for a low-nitrogen burner, which mainly includes components such as a burner head shell 1, an inner air cylinder 2, a porous medium ceramic plate 3, and an internal protective plate 4, and may further include components such as a mounting flange 11, a pressure plate, a flame guide 8, and a thermal insulation gasket 6. Among them, all components except the thermal insulation gasket 6 can be made of high-temperature resistant stainless steel. When the burner head is working, the gas fuel formed by the complete premixing of gas and air can enter the inner air cylinder 2 from one side of the mounting flange 11, enter the interior of the burner head shell 1 from the vent 17 on the inner air cylinder 2, and then overflow through the through hole on the fire hole plate to burn. Among them, the fire hole plate includes two layers, an internal protective plate 4 and a porous medium ceramic plate 3, which can achieve double anti-flashback protection. The flame guide 8 is provided with circular holes or strip-shaped heat dissipation holes, which are used to disturb the flame and stabilize the combustion. The inner air duct 2 can match the required length of the inner air duct according to the length of the combustion head. The inner air duct 2 is provided with closely spaced ventilation openings, the apertures of which gradually increase from the inside to the outside, and the total area of ​​the openings is close to the inlet of the mounting flange, so that the airflow can be evenly distributed under variable load conditions, thereby promoting uniform premixing of the fuel and the air.

[0040] In summary, the burner head disclosed in the embodiment of the present invention achieves the following technical effects by adopting the technical solution as described above.

[0041] The combustion head of the invention has a compact structure, high combustion efficiency and low CO and NOx emissions.

[0042] The burner head of the present invention has a fire hole plate disposed on its fire hole surface, which includes two or more porous medium ceramic plates. The number of porous medium ceramic plates can be adjusted according to the required heat load to reduce the area of ​​a single porous medium ceramic plate, thereby effectively reducing the possibility of the fire hole plate being deformed and broken due to thermal stress caused by the temperature increase. In addition, an internal protective plate is disposed under the porous medium ceramic plate, and the double-layer structure formed together can realize a dual anti-backfire protection function, and the safety performance is more reliable.

[0043] The burner head of the present invention is provided with an internal wind tube, which can realize uniform distribution of airflow under variable load conditions and promote uniform premixing of fuel. The burner of the present invention can realize a combustion mode of completely premixed gas fuel, and the combustion condition is stable.

[0044] As can be seen from the above, the burner head of the present invention has high combustion efficiency and low CO and NOx emissions; it has dual anti-flashback protection functions and reliable safety performance; it can achieve uniform distribution of airflow, promote uniform premixing of fuel, and stable combustion conditions. The burner head of the present invention can be used not only in small and medium-sized industrial heating systems, but also in civil and commercial heating and domestic hot water supply systems.

[0045] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. A person skilled in the art should understand that the technical solutions described in the above embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A porous ceramic burner head for a low nitrogen burner, characterized in that: It comprises a combustion head housing (1) and an inner wind tube (2); A fire hole plate is provided at the top opening of the burner head shell (1), and the fire hole plate includes at least two porous medium ceramic plates (3). The fire hole plate adjusts the number of the porous medium ceramic plates (3) according to the required heat load, and changes the area of ​​a single porous medium ceramic plate (3). An internal protection plate (4) is provided inside each porous medium ceramic plate (3); the internal protection plate (4) is densely provided with circular holes and / or strip holes, the width gap of the strip holes is between 0.5-1.5 mm, the porosity of the strip holes is between 50%-60%, and the thickness is between 1-8 mm; the diameter of the circular holes is between 1-2 mm, and the porosity is between 40%-60%; the thickness of the internal protection plate (4) is between 3-10 mm; The inner wind cylinder (2) is inserted into the combustion head housing (1), and a plurality of ventilation holes (17) are arranged on the surface of the inner wind cylinder (2).

2. The porous ceramic burner head for a low nitrogen burner according to claim 1, characterized in that: The combustion head housing (1) is mainly composed of a front plate (13), an upper plate (14), a lower plate (15) and a rear plate (16); The inner wind tube (2) is inserted into the combustion head housing (1) through a through hole provided on the front end plate (13), and is sealedly connected to the front end plate (13); The upper plate (14) is provided with at least two openings, the internal protection plate (4) is arranged at the openings from the inner side of the upper plate (14), and the porous dielectric ceramic plate (3) is arranged at the openings from the outer side of the upper plate (14); The rear end plate (16) is provided with one or more drainage holes.

3. The porous ceramic burner head for a low nitrogen burner according to claim 2, characterized in that: The upper plate (14) comprises two top surfaces at an angle, each top surface being provided with one or more openings, one or more porous dielectric ceramic plates (3) being provided on the outside of each opening, and one or more internal protective plates (4) being provided on the inside of each opening.

4. The porous ceramic burner head for a low nitrogen burner according to claim 3, characterized in that: A spark guide plate (8) is provided at the edge of the porous medium ceramic plate (3), and a circular heat dissipation hole or a strip heat dissipation hole is opened on the spark guide plate (8).

5. The porous ceramic burner head for a low nitrogen burner according to claim 4, characterized in that: The spark guide piece (8) comprises a first spark guide piece (81) and a second spark guide piece (82), which are respectively located at the top of the two top surfaces.

6. The porous ceramic burner head for a low nitrogen burner according to claim 2, characterized in that: The porous dielectric ceramic plate (3) is fixed on the upper plate (14) via a plurality of pressing plates, and the connection between the porous dielectric ceramic plate (3) and the upper plate (14) is sealed with high temperature resistant glue.

7. The porous ceramic burner head for a low nitrogen burner according to claim 1, characterized in that: The inner air cylinder (2) comprises an air outlet cylinder (10) at the front end and a connecting cylinder (12) at the rear end, wherein the air outlet cylinder (10) is located inside the combustion head shell (1), and the connecting cylinder (12) is located outside the combustion head shell (1), and a mounting flange (11) is provided at the end of the connecting cylinder (12), and the plurality of ventilation openings (17) are closely arranged on the surface of the air outlet cylinder (10).

8. The porous ceramic burner head for a low nitrogen burner according to claim 7, characterized in that: From the front end to the rear end of the inner air cylinder (2), the apertures of the plurality of ventilation openings (17) gradually increase.

9. The porous ceramic burner head for a low nitrogen burner according to claim 7, characterized in that: The total opening area of ​​the multiple ventilation openings (17) is equivalent to the inlet area of ​​the mounting flange (11).

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