Low-nitrogen gas burner

Abstract

The utility model discloses a low-nitrogen gas burner, which relates to the technical field of burners, and comprises a furnace wall, an air supply pipe group and a gas supply pipe group, the furnace wall is provided with a combustion cavity, the air supply pipe group comprises a first air pipe, the first air pipe is connected with the furnace wall and is inserted into the combustion cavity, and a backflow area is formed between the side wall of the first air pipe and the cavity wall of the combustion cavity. A through backflow hole is formed in the side wall of the first air pipe and communicates with the backflow area and the interior of the first air pipe. The fuel gas supply source can supply fuel gas to the combustion cavity through the first fuel gas pipe, high-speed jet fuel gas and air are mixed and then sprayed into the combustion cavity, and smoke generated by combustion can flow back into the first air pipe through the backflow area and the backflow holes of the first air pipe, so that smoke recycling is achieved; and meanwhile, the flue gas can control the oxygen content in the first air pipe, the combustion temperature is controlled through oxygen deficiency, and the generation amount of thermal NOx is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of combustor, concretely relates to a low nitrogen gas combustor. BACKGROUND

[0002] Nitrogen oxide as one of main pollutants in air is an important factor of acid rain and is the main reason of haze (PM2.5) in air. Nitrogen oxide emission in China mainly comes from boiler flue gas emission, and accounts for more than 70% of total nitrogen oxide emission, so reducing the nitrogen oxide emission of boiler is particularly important for nitrogen oxide emission reduction. At present, the low nitrogen combustion technology of industrial gas boiler mainly focuses on reducing the combustion center temperature and reducing the generation of thermal NOx. The main technical means includes fuel and air staged combustion, premixing combustion, flue gas recirculation (FGR) and the like.

[0003] The prior art with publication number CN109631036A discloses a combustion device with ultra-low nitrogen oxide, which is connected with a fan through a flange at one end of a combustion air duct; a furnace body connecting flange is arranged in the middle of the combustion air duct and connected with a furnace body, and a gas inner ring and a gas outer ring are arranged in the inner side and the outer side of the air duct respectively. A gas gun is connected with the gas inner ring, and an outer gas gun is connected with the gas outer ring; the other end of the combustion air duct is connected with a flow straightener, and the flow straightener is connected with a flow body; the inner gas gun is arranged in the flow straightener and the flow body of the combustion air duct, and the inner gas gun is divided into a center gas gun and branch gas guns; a gas injection hole and a premixing injection head are arranged at each gun head; the center gas gun is arranged in the flow straightener, and the branch gas guns are arranged in the flow body.

[0004] However, the combustion device still has some deficiencies, for example, the flue gas generated during combustion of the combustor cannot flow back to the gas injection pipe naturally, flue gas recirculation cannot be achieved, combustion temperature cannot be controlled by oxygen depletion, and the generation amount of thermal NOx cannot be reduced. UTILITY MODEL CONTENTS

[0005] The utility model aims at overcoming the above technical deficiencies, and provides a low nitrogen gas combustor, which solves the technical problem that the flue gas generated during combustion of the combustor in the prior art cannot flow back to the gas injection pipe naturally, flue gas recirculation cannot be achieved, combustion temperature cannot be controlled by oxygen depletion, and the generation amount of thermal NOx cannot be reduced.

[0006] To achieve the above technical purposes, the utility model adopts the following technical scheme:

[0007] The utility model provides a low nitrogen gas combustor, which comprises:

[0008] The furnace wall has a combustion chamber.

[0009] The air supply pipe group comprises a first air pipe connected to the furnace wall and inserted into the combustion chamber, a side wall of the first air pipe is provided with a backflow hole penetrating through, and a cavity wall of the combustion chamber forms a backflow area communicating with the backflow hole.

[0010] The gas supply pipe group comprises a first gas pipe, an air outlet end of the first gas pipe is located inside the first air pipe, the air outlet end sprays high-speed jet flow into the combustion chamber, and the flue gas formed by combustion in the combustion chamber is driven to flow from the backflow area into the first air pipe by pressure difference.

[0011] In some embodiments, the cavity wall of the combustion chamber has a connected conical surface and cylindrical surface, the conical surface is arranged at an obtuse angle with the cylindrical surface, and the conical surface, the cylindrical surface and the side wall of the first air pipe form the backflow area.

[0012] In some embodiments, the air supply pipe group further comprises a second air pipe, the second air pipe is located inside the first air pipe, and an output end of the second air pipe is located in the combustion chamber, and the first gas pipe is located between the inner wall of the first air pipe and the outer wall of the second air pipe.

[0013] In some embodiments, a first air supply channel is formed between the inner wall of the first air pipe and the outer wall of the second air pipe, and the outlet of the first air supply channel is provided with a swirl vane.

[0014] In some embodiments, the number of the first gas pipes is multiple, and the multiple first gas pipes are located in the first air supply channel and arranged around the circumferential side of the second air pipe.

[0015] In some embodiments, the number of the swirl vanes is multiple, and the number of the swirl vanes is consistent with the number of the first gas pipes, and the multiple swirl vanes are located at the outlet of the first air supply channel and arranged around the circumferential side of the second air pipe.

[0016] In some embodiments, the gas supply pipe group further comprises a gas collecting ring, an outlet of the gas collecting ring is connected to the multiple first gas pipes, and an inlet of the gas collecting ring is used to connect a gas supply source.

[0017] In some embodiments, the air supply pipe group further comprises a center air pipe, the center air pipe is located inside the second air pipe, a second air supply channel is formed between the outer wall of the center air pipe and the inner wall of the second air pipe, and a center air supply channel is formed inside the center air pipe.

[0018] In some embodiments, the gas supply pipe group further comprises a second gas pipe, the second gas pipe is inserted into the center air pipe and used to mix air with the center air pipe and enter the combustion chamber.

[0019] In some embodiments, the output end of the second gas pipe is closed, and a plurality of gas through holes are arranged on the circumferential side close to the output end, the gas through holes being communicated with the central air supply channel.

[0020] Compared with the prior art, the low-nitrogen gas burner has the first air pipe for connecting the air blower, the air blower can deliver air to the combustion chamber through the first air pipe, the first gas pipe is used for connecting the gas supply source, the gas supply source can supply gas to the combustion chamber through the first gas pipe, the gas is sprayed in the form of high-speed jet and mixed with air to spray into the combustion chamber, the flue gas generated by combustion in the combustion chamber can pass through the backflow area and then flow back into the first air pipe through the backflow of the first air pipe, so that the flue gas is recirculated, and the oxygen content in the first air pipe can be controlled by the flue gas, the combustion temperature is controlled by the oxygen deficiency, and the generation amount of thermal NOx is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic view of the low-nitrogen gas burner provided by the embodiment of the utility model. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical scheme and advantages of the utility model more clear, the following will be further described in detail by combining with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the utility model, and are not used to limit the utility model.

[0023] In order to solve the technical problem that the flue gas generated by the burner during combustion cannot be backflowed into the gas injection pipe naturally, cannot be recirculated, and cannot control the combustion temperature by oxygen deficiency to reduce the generation amount of thermal NOx, the utility model provides a low-nitrogen gas burner, which can realize that the flue gas generated by the burner during combustion can be backflowed into the gas injection pipe, realize flue gas recirculation, control the combustion temperature by oxygen deficiency, and reduce the generation amount of thermal NOx.

[0024] Please refer to Figure 1 , Figure 1The structure diagram of the low-nitrogen gas burner in an embodiment of the utility model, low-nitrogen gas burner 100 includes furnace wall 1, air supply pipe group and gas supply pipe group, furnace wall 1 has combustion chamber 11, the cavity wall of combustion chamber 11 is non-plane, for example can be cambered or cornered.The air supply pipe group includes first air pipe 2, first air pipe 2 connects furnace wall 1 and inserts combustion chamber 11, the side wall of first air pipe 2 and the cavity wall of combustion chamber 11 form return flow area 12, the side wall of first air pipe 2 is provided with the return flow hole 21 that penetrates, return flow hole 21 communicates return flow area 12 and the inside of first air pipe 2, so that the flue gas generated after combustion chamber 11 passes through combustion can pass through return flow area 12 and enter return flow hole 21, return flow enters the inside of first air pipe 2, to realize flue gas recirculation, and the oxygen content in the inside of first air pipe 2 can be controlled by flue gas, and the generation amount of thermal NOx is reduced by lean oxygen control combustion temperature.

[0025] The gas supply pipe group includes first gas pipe 3, and the gas outlet end of first gas pipe 3 is located in the inside of first air pipe 2.The gas inlet end of first gas pipe 3 is used to connect gas supply source, and the gas supply source can supply gas to first gas pipe 3, and the gas is output from the gas outlet end of first gas pipe 3, mixes with air in first air pipe 2 and then enters combustion chamber 11 to burn.

[0026] The gas supply source makes the gas outlet end of first gas pipe 3 spray in the form of high-speed jet flow by high pressure, and the high-speed gas mixes with air in the inside of first air pipe 2 to form mixed gas flow with large speed and is sprayed into combustion chamber to burn.As the air pressure is small in the position with large air flow speed and the air pressure is large in the position with small air flow speed, the air pressure is small in the position of first air pipe close to return flow hole 21, and the air pressure is large in return flow area, so that the flue gas generated by combustion in combustion chamber can pass through return flow area, then pass through the return flow hole of first air pipe and return flow into the inside of first air pipe, to realize flue gas recirculation.

[0027] In one of the embodiments, please refer to Figure 1 The cavity wall of combustion chamber 11 has connected taper surface 13 and cylindrical surface 14, and the taper surface 13 and cylindrical surface 14 are arranged at obtuse angle, and the return flow area 12 is formed between the taper surface 13, cylindrical surface 14 and the side wall of first air pipe 2.In this embodiment, the return flow area 12 formed by the obtuse angle arrangement of taper surface 13 and cylindrical surface 14 can make the flue gas in combustion chamber 11 flow smoothly to return flow hole 21 and flow into the inside of first air pipe 2 quickly, to accelerate flue gas recirculation.In other embodiments, the cavity wall of combustion chamber 11 can also be provided with multiple taper surfaces 13 or cylindrical surfaces 14 that are connected in sequence, to make the flue gas in combustion chamber 11 flow more smoothly to return flow hole 21.

[0028] In one of the embodiments, please refer to Figure 1, the air supply pipe group further comprises a second air pipe 4, the second air pipe 4 is located inside the first air pipe 2, and an output end of the second air pipe 4 is located in the combustion cavity 11; an air inlet end of the second air pipe 4 can be connected to an air supply source, such as a blower, which can supply air to the combustion cavity 11 through the second air pipe 4 when in operation, thereby providing oxygen for combustion of the combustion cavity 11, so that the gas can be fully combusted in the combustion cavity 11, and the generation of thermal NOx is reduced. The first gas pipe 3 is located between the inner wall of the first air pipe 2 and the outer wall of the second air pipe 4, and the first air pipe 2 and the second air pipe 4 are coaxially arranged, so that a first air supply channel 22 formed between the inner wall of the first air pipe 2 and the outer wall of the second air pipe 4 is uniformly ventilated.

[0029] In one embodiment, referring to Figure 1 , the outlet of the first air supply channel 22 is provided with swirl vanes 23, which are similar in shape to the blades of an electric fan; after the air and gas are mixed, the mixed air and gas pass through the swirl vanes 23, so that the air and gas are rotated and mixed to enter the combustion cavity 11, thereby improving the mixing quality of the air and gas, and the gas / air swirl is sprayed towards the flame at the center of the combustion cavity 11 to assist combustion, so that the purpose of balanced combustion is achieved.

[0030] In one embodiment, referring to Figure 1 , the number of swirl vanes 23 is consistent with the number of first gas pipes 3, and the plurality of swirl vanes 23 are arranged around the periphery of the second air pipe 4. The first air supply channel 22 is an annular channel, and the plurality of swirl vanes 23 cover the outlet of the first air supply channel 22, so that all the air and gas mixed in the first air supply channel 22 can pass through the swirl vanes 23 to enter the combustion cavity 11.

[0031] In one embodiment, referring to Figure 1 , the gas supply pipe group further comprises a gas collecting ring 5, the outlet of the gas collecting ring 5 is connected to the plurality of first gas pipes 3, and the inlet of the gas collecting ring 5 is used to connect a gas supply source. The gas supply source can simultaneously deliver gas to the plurality of first gas pipes 3 through one gas collecting ring 5, which is beneficial to improve the gas delivery efficiency. In addition, the plurality of first gas pipes 3 are mixed with air in the first air supply channel 22 at the same time, which can improve the combustion efficiency of the combustion cavity 11.

[0032] In one embodiment, referring to Figure 1 , the air supply pipe group further comprises a center air pipe 6, the center air pipe 6 is located inside the second air pipe 4, a second air supply channel 23 is formed between the outer wall of the center air pipe 6 and the inner wall of the second air pipe 4, and a center air supply channel 61 is formed inside the center air pipe 6. In this embodiment, the inlet of the center air pipe 6 can be connected to another blower, which can provide additional oxygen for the combustion cavity 11 through the center air pipe 6, so that the oxygen supply is more sufficient.

[0033] In one embodiment, please refer to Figure 1 , the gas supply pipe group further comprises a second gas pipe 7, which is inserted into the central air pipe 6 and used for mixing air in the central air pipe 6 into the combustion chamber 11. In this embodiment, the second gas pipe 7 is used to connect a gas supply source, which can supply gas to the second gas pipe 7, and the gas is output from the gas outlet of the second gas pipe 7, pre-mixed with air in the central air pipe 6, and then mixed with air in the second air supply channel 23 for combustion.

[0034] In one embodiment, please refer to Figure 1 , the output end of the second gas pipe 7 is closed, and a plurality of gas through holes 71 are arranged on the side near the output end, which are in communication with the central air supply channel 61. The gas in the second gas pipe 7 can be output to the central air supply channel 61 through the plurality of gas through holes 71 at the same time, and mixed with air in the central air supply channel 61, which can be more uniformly mixed with air.

[0035] In order to better understand the present application, the following will be combined Figure 1 to explain the technical scheme of the present application in detail:

[0036] The low-nitrogen gas burner 100 provided by the present application has a first air pipe 2 which can be used to connect a blower, and the blower can transport air to the combustion chamber 11 through the first air pipe 2. The first gas pipe 3 can be used to connect a gas supply source, and the gas supply source can supply gas to the combustion chamber 11 through the first gas pipe 3, which is sprayed in the form of high-speed jet and mixed with air and sprayed into the combustion chamber 11. Since the air pressure is smaller at the position with large air flow rate and the air pressure is larger at the position with small air flow rate, the flue gas generated by combustion in the combustion chamber 11 can pass through the backflow area 12 and then pass through the backflow hole 12 of the first air pipe to flow into the inside of the first air pipe 2, so as to realize flue gas recirculation, and the flue gas can control the oxygen content in the first air pipe 2, control the combustion temperature by oxygen deficiency, and reduce the generation amount of thermal NOx.

[0037] The specific embodiments of the present application described above do not constitute a limitation on the protection scope of the present application. Any other corresponding changes and modifications made according to the technical concept of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A low-nitrogen gas burner, characterized by, The application relates to a furnace wall with a combustion chamber, a supply air pipe group including a first air pipe connected to the furnace wall and inserted into the combustion chamber, a side wall of the first air pipe being provided with a backflow hole penetrating through the side wall and forming a backflow area communicating with the backflow hole between a cavity wall of the combustion chamber, and a supply gas pipe group including a first gas pipe, an air outlet end of the first gas pipe being located inside the first air pipe, the air outlet end being jetted towards the combustion chamber through a high-speed jet flow to drive flue gas formed by combustion in the combustion chamber to flow into the first air pipe from the backflow area through a pressure difference. The cavity wall of the combustion chamber is provided with a connected taper surface and a cylindrical surface, the taper surface is arranged at an obtuse angle with the cylindrical surface, and the taper surface, the cylindrical surface and the side wall of the first air pipe form the backflow area. The supply air pipe group further includes a second air pipe, the second air pipe is located inside the first air pipe, and an output end of the second air pipe is located in the combustion chamber, and the first gas pipe is located between an inner wall of the first air pipe and an outer wall of the second air pipe. A first air supply channel is formed between the inner wall of the first air pipe and the outer wall of the second air pipe, and the outlet of the first air supply channel is provided with a cyclone vane.

2. The low-nitrogen gas burner according to claim 1, characterized in that, The number of the first gas pipes is multiple, and the multiple first gas pipes are located in the first air supply channel and arranged around the circumferential side of the second air pipe.

3. The low-nitrogen gas burner according to claim 1, characterized in that, The number of the cyclone vanes is multiple, and the number of the cyclone vanes is consistent with the number of the first gas pipes, and the multiple cyclone vanes are located at the outlet of the first air supply channel and arranged around the circumferential side of the second air pipe.

4. The low-nitrogen gas burner according to claim 3, characterized in that, The supply gas pipe group further includes a gas collecting ring, an outlet of the gas collecting ring is connected to the multiple first gas pipes, and an inlet of the gas collecting ring is used for connecting a gas supply source.

5. The low-nitrogen gas burner according to claim 4, characterized in that, The supply air pipe group further includes a center air pipe, the center air pipe is located inside the second air pipe, a second air supply channel is formed between an outer wall of the center air pipe and an inner wall of the second air pipe, and a center air supply channel is formed inside the center air pipe.

6. The low nitrogen gas burner according to claim 5, characterized in that: The supply gas pipe group further includes a second gas pipe, the second gas pipe is inserted into the center air pipe and used for mixing air in the center air pipe and entering the combustion chamber.

7. The low-nitrogen gas burner according to claim 3, characterized in that, An output end of the second gas pipe is closed, multiple gas through holes penetrating through the circumferential side close to the output end are formed in the output end, and the gas through holes communicate with the center air supply channel.

8. The low-nitrogen gas burner according to claim 3, characterized in that, ​ 9. The low-nitrogen gas burner according to claim 8, characterized in that ​ 10. The low-nitrogen gas burner according to claim 9, characterized in that ​

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