A multi-injection staged low-nitrogen gas burner

Abstract

The application relates to a multi-injection staged low-nitrogen gas burner, and relates to a low-nitrogen gas burner. The application is aimed at solving the problems of uneven fuel injection and high thermal NOx emission of the existing gas burners. The application organically combines the multi-injection dispersion combustion technology and the flue gas recirculation technology, that is, the radial gas injection ports and the porous swirled vanes arranged on the duty gas pipe realize the multi-injection of the duty gas, realize the uniform distribution of the gas in the combustion area, and ensure the efficient mixing of the air and the gas. Secondly, the Venturi tube can roll the backflow flue gas in the furnace, so that the gas and the flue gas enter the gas mixing pipe through the mixing pipe expansion and the mixing pipe roll suction, and then are injected into the furnace, form the flue gas backflow, effectively reduce the oxygen concentration in the combustion area, absorb heat, thereby reducing the combustion temperature and reducing the generation of thermal NOx. The application belongs to the technical field of boiler combustion devices.

Description

TECHNICAL FIELD

[0001] The present application relates to a gas burner, in particular to a multi-jet staged low-nitrogen gas burner, belonging to the technical field of boiler combustion device. BACKGROUND

[0002] The existing gas burners mostly use the traditional nozzle to jet gas, the fuel jet is not uniform enough, the local high temperature phenomenon is still serious, thereby promoting the generation of thermal NOx, and further making the emission of thermal NOx high.

[0003] In view of the above technical problems, how to propose a new low-nitrogen gas burner has become a problem to be solved by the technical personnel in the field. SUMMARY

[0004] In view of the above technical problems, how to propose a new low-nitrogen gas burner has become a problem to be solved by the technical personnel in the field.

[0005] The technical scheme of the present application is: a multi-jet staged low-nitrogen gas burner, comprising a duty gas pipe, a center air inlet pipe, a duty sleeve, a Venturi tube, a plurality of outer circle main flame nozzles and a plurality of inner circle main flame nozzles.

[0006] The outlet of the duty gas pipe is provided with a plurality of radial gas injection ports in a circumferential array, and a plurality of porous cyclone blades are fixedly connected to the duty gas pipe in a circumferential array.

[0007] The back flow side of the porous cyclone blade is provided with a plurality of axial gas injection holes, and the flow side of the porous cyclone blade is provided with an L-shaped gas branch pipe, and the two ends of the L-shaped gas branch pipe are communicated with the duty gas pipe and the axial gas injection hole.

[0008] The center air inlet pipe, the outer circle main flame nozzle and the inner circle main flame nozzle are fixedly connected to the furnace wall.

[0009] The center air inlet pipe and the duty sleeve are sequentially sleeved on the duty gas pipe according to the direction of gas jet, the Venturi tube is coaxially sleeved on the duty sleeve, and the outlet of the center air inlet pipe is inserted into the inlet of the Venturi tube.

[0010] The plurality of outer circle main flame nozzles and the plurality of inner circle main flame nozzles are arranged around the center air inlet pipe in an annular array, the outer circle main flame nozzles are arranged on a circle with a diameter of D1, the inner circle main flame nozzles are arranged on a circle with a diameter of D2, and D1>D2.

[0011] The outer circle main flame nozzle and the inner circle main flame nozzle each comprise a main flame gas pipe, a mixed pipe flared portion and a gas mixing pipe.

[0012] The outlet of the main flame gas pipe is inserted into the inlet of the gas mixing pipe, the small end of the mixing pipe flared is fixed to the inlet of the gas mixing pipe, the gas mixing pipe is provided with a mixing pipe entraining opening, and the jet opening of the gas mixing pipe is a bevelled jet opening.

[0013] The bevel angle of the gas mixing pipe in the outer circle main flame jet pipe faces away from the Venturi pipe, and the bevel angle of the gas mixing pipe in the inner circle main flame jet pipe faces towards the Venturi pipe.

[0014] Compared with the prior art, the present application has the following effects:

[0015] The present application organically combines the multiple jet dispersion combustion technology and the flue gas recirculation technology, and realizes a stable and low-pollution combustion process, namely:

[0016] The multiple jet of the standby gas is realized through the radial gas jet opening 17 and the porous rotating flow vane 18 arranged on the standby gas pipe 1, the uniform distribution of the gas in the combustion area is realized, the efficient mixing of the air and the gas is ensured, the generation of thermal NOx is inhibited, and the pollutant emission can be significantly reduced while meeting the requirement of efficient combustion.

[0017] Secondly, the Venturi pipe 6 can entrain the backflow flue gas in the furnace, the gas and the flue gas enter the gas mixing pipe 13 through the mixing pipe flared 11 and the mixing pipe entraining opening 12, and then are injected into the furnace, thereby forming the flue gas backflow. The backflow flue gas effectively reduces the oxygen concentration in the combustion area, absorbs heat, thereby reducing the combustion temperature and reducing the generation of thermal NOx. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic diagram of the present application;

[0019] Figure 2 is a schematic diagram of the arrangement of the standby gas pipe 1, the L-shaped gas branch pipe 15 and the porous rotating flow vane 18 of the present application;

[0020] Figure 3 is a front view of the present application;

[0021] Figure 4 is a schematic diagram of the flame and the flue gas in the furnace when the present application is used;

[0022] In the figure: 1, standby gas pipe; 2, center air inlet pipe; 3, standby sleeve flared; 4, standby sleeve; 5, standby sleeve flared; 6, Venturi pipe; 7, Venturi entraining opening; 8, Venturi flared; 9, main flame gas pipe; 10, main flame gas flared; 11, mixing pipe flared; 12, mixing pipe entraining opening; 13, gas mixing pipe; 15, L-shaped gas branch pipe; 16, axial gas jet hole; 17, radial gas jet opening; 18, porous rotating flow vane. DETAILED DESCRIPTION

[0023] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in this embodiment will be clearly and completely described below with reference to the accompanying drawings of the present invention.

[0024] Specific implementation method 1: Combination Figures 1 to 4 To illustrate this embodiment, a multi-injection staged low-nitrogen gas burner of this embodiment includes a service gas pipe 1, a central air inlet pipe 2, a service sleeve 4, a venturi tube 6, a plurality of outer ring main flame nozzles and a plurality of inner ring main flame nozzles.

[0025] The outlet of the duty gas pipe 1 is provided with a number of radial gas injection ports 17 in a circular array. Each radial gas injection port 17 sprays gas evenly into the furnace to form a more dispersed gas jet flow. Therefore, the gas can be more evenly distributed in the combustion area and fully mixed with the air for combustion, avoiding local overheating caused by uneven gas injection in traditional burners.

[0026] A number of porous swirl blades 18 are fixedly connected to the duty gas pipe 1 in a circumferential array. A number of axial gas injection holes 16 are opened on the backflow side of the porous swirl blade 18. An L-shaped gas branch pipe 15 is installed on the frontflow side of the porous swirl blade 18. The two ends of the L-shaped gas branch pipe 15 are respectively connected to the duty gas pipe 1 and the axial gas injection holes 16. Part of the duty gas in the duty gas pipe 1 enters the hollow porous swirl blade 18 through the L-shaped gas branch pipe 15, and is then ejected from the multiple axial gas injection holes 16 on the blade, which can effectively diffuse the ejected gas flow and fully mix it with the air, so as to realize multiple injections of the gas in the duty gas pipe 1 through the axial gas injection holes 16 and the radial gas injection ports 17.

[0027] The central air inlet pipe 2, the outer circle main flame nozzle and the inner circle main flame nozzle are all fixedly connected to the furnace wall.

[0028] The central air inlet pipe 2 and the service sleeve 4 are sequentially sleeved onto the service gas pipe 1 in the direction of airflow injection. The inner circumference of the central air inlet pipe 2 and the outer circumference of the service gas pipe 1 form an air passage. The venturi tube 6 is coaxially sleeved onto the service sleeve 4, and the outlet of the central air inlet pipe 2 is inserted into the inlet of the venturi tube 6. This arrangement allows the inlet of the venturi tube 6 to draw in the return flue gas from the furnace. A portion of the flue gas is ejected into the furnace through the back of the venturi tube 6, while another portion of the flue gas is mixed with the air ejected from the central air inlet pipe 2 and introduced into the service sleeve 4. After passing through the porous swirl blades 18, the mixed gas of air and flue gas has a certain swirl intensity, which accelerates the mixing speed with the gas, further increases the mixing uniformity, forms a diffusion flame, and reduces the generation of thermal NOx.

[0029] The outer circle of main flame nozzles and the inner circle of main flame nozzles are arranged around the central air inlet pipe 2 in the form of an annular array, the outer circle of main flame nozzles is arranged on a circle with a diameter D1, the inner circle of main flame nozzles is arranged on a circle with a diameter D2, and D1>D2.

[0030] The outer circle of main flame nozzles and the inner circle of main flame nozzles each include a main flame gas pipe 9, a mixing pipe flared portion 11, and a gas mixing pipe 13.

[0031] The outlet of the main flame gas pipe 9 is inserted into the inlet of the gas mixing pipe 13, the small end of the mixing pipe flared portion 11 is fixed to the inlet of the gas mixing pipe 13, the gas mixing pipe 13 is provided with a mixing pipe entrainment opening 12, the outlet of the gas mixing pipe 13 is a bevelled outlet, and further, the bevel angle of the bevelled outlet is 45°.

[0032] The bevel angle of the gas mixing pipe 13 in the outer circle of main flame nozzles faces away from the venturi pipe 6, and the bevel angle of the gas mixing pipe 13 in the inner circle of main flame nozzles faces towards the venturi pipe 6. In this way, the gas emitted by the outer circle of main flame nozzles is deflected in a direction away from the venturi pipe 6, and the gas emitted by the inner circle of main flame nozzles is deflected in a direction towards the venturi pipe 6, which can make the gas uniformly distributed in the combustion area, thereby making the main flame fat and long in the furnace, improving the combustion efficiency, improving the dispersibility of the main flame, reducing the local high temperature area, and reducing the generation of nitrogen oxides.

[0033] Specific implementation method two: combining Figures 1 to 4 In this implementation method, the inner circumferential surface of the venturi pipe 6 and the outer circumferential surface of the duty gas pipe 1 are connected by a rib plate, and the venturi pipe 6 includes a venturi entrainment opening 7, a throat pipe, and a venturi flared portion 8 which are coaxially and fixedly connected in sequence.

[0034] Further, the venturi entrainment opening 7 and the venturi flared portion 8 are both horn-shaped pipes, and the throat pipe is a hollow cylindrical pipe, the two ends of the throat pipe are fixedly connected to the small end of the venturi entrainment opening 7 and the small end of the venturi flared portion 8 respectively. In this way, the venturi entrainment opening 7 can entrain the backflowing flue gas in the furnace, mix the flue gas with air in the venturi pipe 6, and then enter the furnace through the venturi flared portion 8, thereby introducing the flue gas generated after combustion into the combustion area again, effectively reducing the oxygen concentration in the combustion area, reducing the combustion temperature, and further reducing the generation of thermal NOx.

[0035] The other components and connection methods are the same as those in the first specific implementation method.

[0036] Specific implementation method three: combining Figures 1 to 4 In this implementation method, the inner circumferential surface of the central air inlet pipe 2 and the outer circumferential surface of the duty gas pipe 1 are connected by a rib plate, and a tapered pipe with gradually reduced diameter is integrally arranged at the outlet of the central air inlet pipe 2, and the tapered pipe is inserted into the venturi entrainment opening 7.

[0037] Other components and connection modes are the same as those in Embodiments 1-2.

[0038] Embodiment 4: Combination Figures 1 to 4 In this embodiment, the inlet of the duty sleeve 4 is coaxially fixed with the duty sleeve neck 3, and the outlet of the duty sleeve 4 is coaxially fixed with the duty sleeve flange 5.

[0039] Further, the duty sleeve neck 3 and the duty sleeve flange 5 are both trumpet-shaped tubes, and the duty sleeve 4 is a hollow cylindrical tube, the two ends of which are fixed with the large end of the duty sleeve neck 3 and the small end of the duty sleeve flange 5, respectively.

[0040] Other components and connection modes are the same as those in Embodiments 1-3.

[0041] Embodiment 5: Combination Figures 1 to 4 In this embodiment, the outlet of the main flame gas tube 9 is integrally provided with the main flame gas neck 10 with gradually reduced diameter, and the main flame gas neck 10 is fixed with the gas mixing tube 13 through a rib plate. In this way, the gas is accelerated when passing through the main flame gas neck 10, and the gas entrains the backflow flue gas in the furnace chamber, so that the gas and the flue gas enter the gas mixing tube 13 through the mixing tube flange 11 and the mixing tube entrainment 12, and then are injected into the furnace chamber, so as to realize the function of the flue gas in absorbing heat, reducing the flame temperature, and further reducing the generation of thermal NOx.

[0042] Other components and connection modes are the same as those in Embodiments 1-4.

[0043] Embodiment 6: Combination Figures 1 to 4 In this embodiment, the number of the outer circle main flame nozzle and the inner circle main flame nozzle is both 6. Other components and connection modes are the same as those in Embodiments 1-5.

[0044] Working principle

[0045] The outlet of the duty gas pipe 1 is provided with a radial gas injection port 17, which uniformly injects gas into the furnace, so that the gas can be more evenly distributed in the combustion area and fully mixed with the air for combustion; secondly, a number of porous swirl blades 18 are fixedly connected to the duty gas pipe 1, and a number of axial gas injection holes 16 are provided on the backflow side of the porous swirl blade 18. An L-shaped gas branch pipe 15 is installed on the frontflow side of the porous swirl blade 18, and the two ends of the L-shaped gas branch pipe 15 are respectively connected to the duty gas pipe 1 and the axial gas injection holes 16. Part of the duty gas in the duty gas pipe 1 enters the hollow porous swirl blade 18 through the L-shaped gas branch pipe 15, and is then ejected from the multiple axial gas injection holes 16 on the blade, which can effectively diffuse the ejected gas flow and fully mix with the air, so as to realize multiple injections of the gas in the duty gas pipe 1 through the axial gas injection holes 16 and the radial gas injection ports 17.

[0046] The central air inlet pipe 2 and the duty sleeve 4 are sequentially sleeved on the duty gas pipe 1 according to the direction of air flow injection. The venturi tube 6 is coaxially sleeved on the duty sleeve 4. The outlet of the central air inlet pipe 2 is inserted into the inlet of the venturi tube 6 to realize the reflux flue gas in the furnace at the inlet of the venturi tube 6. Part of the flue gas is sprayed into the furnace through the back of the venturi tube 6. After the flue gas is reintroduced into the combustion area, the oxygen concentration in the combustion area is effectively reduced, the combustion temperature is reduced, and the generation of thermal NOx is further reduced; another part of the flue gas is mixed with the air ejected from the central air inlet pipe 2 and is injected into the duty sleeve 4. The mixed gas of air and flue gas has a certain swirl intensity after passing through the porous swirl blades 18, which accelerates the mixing speed with the gas, further increases the mixing uniformity, forms a diffusion flame, and reduces the generation of thermal NOx.

[0047] Several outer ring main flame nozzles and several inner ring main flame nozzles are arranged around the central air inlet pipe 2 in a circular array, and both the outer ring main flame nozzles and the inner ring main flame nozzles include a main flame gas pipe 9, a mixing pipe expansion port 11 and a gas mixing pipe 13, and the nozzle of the gas mixing pipe 13 is a bevel nozzle.

[0048] The bevel angle of the gas mixing tube 13 in the outer ring main flame nozzle is away from the Venturi tube 6, and the bevel angle of the gas mixing tube 13 in the inner ring main flame nozzle is toward the Venturi tube 6. With this arrangement, the gas discharged from the outer ring main flame nozzle is deflected in the direction away from the Venturi tube 6, and the gas discharged from the inner ring main flame nozzle is deflected in the direction of the Venturi tube 6, which can make the gas evenly distributed in the combustion area, thereby making the main flame fatter and longer in the furnace, improving combustion efficiency, improving the dispersion of the main flame, reducing local high-temperature areas, and reducing the generation of nitrogen oxides.

[0049] The application has been disclosed in the above preferred embodiments, but is not intended to limit the application, and any simple modification, equivalent change and modification made by any person skilled in the art according to the technical essence of the application without departing from the technical solution of the application shall still fall within the scope of the technical solution of the application.

Claims

1. A multi-injection staged low-nitrogen gas burner, characterized by: It comprises a duty gas pipe (1), a central air inlet pipe (2), a duty sleeve (4), a venturi tube (6), a plurality of outer ring main flame nozzles and a plurality of inner ring main flame nozzles; The outlet of the duty gas pipe (1) is provided with a plurality of radial gas injection ports (17) in a circumferential array, and the duty gas pipe (1) is fixedly connected with a plurality of porous swirl blades (18) in a circumferential array; The backflow side of the porous swirl blade (18) is provided with a plurality of axial gas injection holes (16), and the frontflow side of the porous swirl blade (18) is provided with an L-shaped gas branch pipe (15), and the two ends of the L-shaped gas branch pipe (15) are respectively connected to the duty gas pipe (1) and the axial gas injection hole (16); The central air inlet pipe (2), the outer ring main flame nozzle and the inner ring main flame nozzle are all fixedly connected to the furnace wall; The central air inlet pipe (2) and the duty sleeve (4) are sequentially sleeved on the duty gas pipe (1) according to the direction of airflow injection, the venturi tube (6) is coaxially sleeved on the duty sleeve (4), and the outlet of the central air inlet pipe (2) is inserted into the inlet of the venturi tube (6); A plurality of outer ring main flame nozzles and a plurality of inner ring main flame nozzles are arranged around the central air inlet pipe (2) in a circular array, and the outer ring main flame nozzles are arranged on a circle with a diameter of D1, and the inner ring main flame nozzles are arranged on a circle with a diameter of D2, where D1>D2; The outer ring main flame nozzle and the inner ring main flame nozzle both include a main flame gas pipe (9), a mixing pipe expansion port (11) and a gas mixing pipe (13); The outlet of the main flame gas pipe (9) is inserted into the inlet of the gas mixing pipe (13), the small end of the mixing pipe expansion port (11) is fixedly connected to the inlet of the gas mixing pipe (13), the gas mixing pipe (13) is provided with a mixing pipe suction port (12), and the nozzle of the gas mixing pipe (13) is an oblique nozzle; The bevel angle of the gas mixing tube (13) in the outer main flame nozzle is away from the venturi tube (6), and the bevel angle of the gas mixing tube (13) in the inner main flame nozzle is toward the venturi tube (6).

2. The multi-injection staged low-nitrogen gas burner according to claim 1, characterized in that: The inner circumference of the venturi tube (6) is connected to the outer circumference of the duty gas pipe (1) via ribs. The venturi tube (6) comprises a venturi suction port (7), a throat pipe and a venturi expansion port (8) which are coaxially fixed in sequence.

3. The multi-injection staged low-nitrogen gas burner according to claim 2, characterized in that: The inner circumference of the central air inlet pipe (2) is connected to the outer circumference of the duty gas pipe (1) via ribs, and a tapered pipe with a gradually decreasing diameter is integrally provided at the outlet of the central air inlet pipe (2), and the tapered pipe is inserted into the Venturi suction port (7).

4. The multi-injection staged low-nitrogen gas burner according to claim 3, characterized in that: The inlet of the duty sleeve (4) is coaxially fixedly connected with the duty sleeve shrinkage (3), and the outlet of the duty sleeve (4) is coaxially fixedly connected with the duty sleeve expansion (5).

5. The multi-injection staged low-nitrogen gas burner according to claim 4, characterized in that: The duty sleeve constriction (3) and the duty sleeve expansion (5) are both trumpet-shaped tubes, the duty sleeve (4) is a hollow cylindrical tube, and the two ends of the duty sleeve (4) are respectively fixedly connected to the large end of the duty sleeve constriction (3) and the small end of the duty sleeve expansion (5).

6. The multi-injection staged low-nitrogen gas burner according to claim 5, characterized in that: A main flame gas constriction (10) with a gradually decreasing diameter is integrally provided at the outlet of the main flame gas pipe (9), and the main flame gas constriction (10) is fixedly connected to the gas mixing pipe (13) via a rib plate.

7. The multi-injection staged low-nitrogen gas burner according to claim 6, characterized in that: The number of the outer ring main flame nozzles and the number of the inner ring main flame nozzles are both 6.

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