Dual-injection low-nitrogen burner

Abstract

The present application relates to the technical field of burner, disclose a kind of double injection low-nitrogen burner, the double injection low-nitrogen burner is applied to boiler furnace;Burner includes air flow guide cylinder, premixed gas inlet pipe and air staging flow guide cylinder;Premixed gas inlet pipe top is provided with premixed gas flow guide pipe;Premixed gas flow guide pipe is provided with premixed gas injection hole;The end of air flow guide cylinder is sequentially coaxially provided with mixed gas contraction section and mixed gas flow guide cylinder;Air flow guide cylinder outside is equipped with injection gas ring cavity;Air flow guide cylinder is provided with injection gas inlet pipe;Injection gas ring cavity is connected with injection gas inlet pipe, and injection gas ring cavity end is uniformly provided with injection gas flow guide pipe;Injection gas flow guide pipe end is sequentially provided with injection contraction section, injection gas injection hole and injection mixing section;Injection mixing section is provided with one flue gas entrainment structure between every two;The present application further reduces the NOx generated in combustion process, guarantees the stable, safe operation of burner.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of burners, and particularly relates to a double-ejection low-nitrogen burner. BACKGROUND

[0002] Environmental problems are becoming more and more serious with the development of society and have attracted attention from the society at home and abroad. In China, the problem of environmental pollution is also becoming increasingly serious, the frequency of air pollution is increasing, and the national environmental protection standards are also improving. The original combustion technology cannot meet the national standards, and the combustion technology and design level need to be further improved to control the emissions of the burner.

[0003] The burner is an important part of the industrial boiler and is the main equipment for releasing fuel energy into heat. With the increasingly stringent environmental protection requirements, the application of the gas burner belonging to clean combustion is also widespread. The nozzle structure of the gas burner has a decisive effect on the emission of pollutants generated in the combustion process, and the design and processing level of the burner nozzle structure determines the required combustion load and the safe and stable operation of the boiler in production.

[0004] Most of the existing burners adopt diffusion combustion. In order to ensure sufficient combustion of fuel, the burner generally adopts a design method of good fuel and air mixing, but this method has concentrated flame, high combustion temperature, and very large NOx emission value. In order to reduce NOx while ensuring sufficient combustion of fuel and ensuring stable and safe operation of the burner, it is a problem that needs to be solved by designers. SUMMARY

[0005] The purpose of the present application is to provide a double-ejection low-nitrogen burner to solve the problem of how to further reduce the NOx generated in the combustion process under the premise of adopting fuel and air mixing combustion and ensure the stable and safe operation of the burner in the prior art.

[0006] To achieve the above technical purpose, the technical scheme adopted by the present application is as follows:

[0007] A double-ejection low-nitrogen burner is applied to a boiler furnace.

[0008] The burner comprises an air guide cylinder, a premixed gas inlet pipe and an air staged guide cylinder; the air guide cylinder and the air staged guide cylinder are coaxially arranged; the top of the premixed gas inlet pipe is uniformly provided with a plurality of premixed gas guide pipes in the circumferential direction; the premixed gas guide pipes are uniformly provided with a plurality of premixed gas injection holes; the end of the air staged guide cylinder away from the premixed gas inlet pipe is provided with a first mixed gas center outlet; the end of the air guide cylinder is coaxially provided with a mixed gas contraction section and a mixed gas guide cylinder in sequence; the end face of the mixed gas guide cylinder away from the air guide cylinder is uniformly provided with a plurality of mixed gas injection holes;

[0009] The air guide cylinder is sleeved with an ejector gas ring cavity; the air guide cylinder is provided with an ejector gas inlet pipe; the ejector gas ring cavity is connected with the ejector gas inlet pipe, and the ejector gas ring cavity is uniformly provided with a plurality of ejector gas guide pipes at the end; the end of the ejector gas guide pipe is coaxially provided with an ejector contraction section, an ejector gas injection hole and an ejector mixing section in sequence; the ejector gas injection hole and the ejector mixing section are separately coaxially installed; one flue gas entrainment structure is arranged between every two ejector mixing sections.

[0010] Further, the flue gas entrainment structure is an arc-shaped baffle.

[0011] Further, the air staging guide cylinder is uniformly provided with a plurality of first mixed gas cyclone vanes and a plurality of first mixed gas cyclone outlets at the end away from the premixed gas inlet pipe.

[0012] Further, a plurality of second mixed gas cyclone vanes are arranged between the premixed gas guide pipe and the first mixed gas cyclone vane; the plurality of second mixed gas cyclone vanes are uniformly distributed on the outer side of the air staging guide cylinder.

[0013] Further, the premixed gas guide pipe is 3-8 in number.

[0014] Further, the first mixed gas cyclone vane is 6-36 in number.

[0015] Further, the second mixed gas cyclone vane is 6-36 in number.

[0016] Further, the ejector gas guide pipe is 4-18 in number.

[0017] Further, the ejector mixing section is 4-18 in number.

[0018] Further, the flue gas entrainment structure is 4-18 in number.

[0019] The application adopting the above technical solution has the following advantages:

[0020] 1. The mixing of air and gas is strengthened, the mixing is more uniform, and the combustion efficiency is improved;

[0021] 2. The double flue gas entrainment structure is arranged to strengthen the entrainment and staging effect of flue gas, and further reduce;

[0022] 3. The central premixed flame makes the mixing of air and gas more uniform, improves the combustion efficiency, and reduces the emission of nitrogen oxides;

[0023] 4. The staging premixing makes the mixing of gas and air more sufficient and uniform. BRIEF DESCRIPTION OF DRAWINGS

[0024] The application can be further illustrated by the non-limiting embodiments shown in the drawings.

[0025] Figure 1 is a structural schematic diagram of a double-ejecting low-nitrogen combustor of the application;

[0026] Figure 2 is a top view of a double-ejecting low-nitrogen combustor of the application;

[0027] Figure 3 is a perspective view of a double-ejecting low-nitrogen combustor of the application;

[0028] Figure 4 is a right view of a double-ejecting low-nitrogen combustor of the application.

[0029] The main element symbols are explained as follows:

[0030] Air guide cylinder 1; premixed gas inlet pipe 2; premixed gas guide pipe 3; premixed gas injection hole 4; air staging guide cylinder 5; secondary mixed gas spiral vane 6; primary mixed gas spiral vane 7; primary mixed gas spiral outlet 8; primary mixed gas center outlet 9; ejecting gas inlet pipe 10; ejecting gas ring cavity 11; ejecting gas guide pipe 12; ejecting contraction section 13; ejecting gas injection hole 14; ejecting mixing section 15; mixed gas contraction section 16; mixed gas guide cylinder 17; mixed gas injection hole 18; mounting flange 19; screw hole 20; flue gas entrainment structure 21; secondary mixed gas area 22; primary mixed gas area 23; gas-flue gas mixing area 24; mixed gas-flue gas mixing area 25; air passage 26. DETAILED DESCRIPTION

[0031] The application will be described in detail below in conjunction with the drawings and specific embodiments. It should be noted that similar or identical parts are denoted by the same reference numerals in the drawings or description, and the implementation not shown or described in the drawings is known to those skilled in the art. In addition, the directional terms mentioned in the embodiments, such as “up”, “down”, “top”, “bottom”, “left”, “right”, “front”, “back”, etc., are only the directions of the drawings and are not intended to limit the protection scope of the application.

[0032] As Figures 1-4The application discloses a double-injection low-nitrogen burner applied to a boiler furnace, which comprises an air guide cylinder 1, a premixed gas inlet pipe 2 and an air staging guide cylinder 5; the air guide cylinder 1 and the air staging guide cylinder 5 are coaxially arranged; an air passage (26) is formed in the air guide cylinder 1, which is used as a passage for air flow and guides the air to the boiler furnace; the air enters the burner from the air passage (1), is divided into two parts after passing through the air staging guide cylinder 5, one part of the air flows from the inside of the air staging guide cylinder 5 to form primary air, and the other part of the air flows between the air guide cylinder 1 and the air staging guide cylinder 5 to form secondary air.

[0033] The premixed gas inlet pipe 2 is used as a passage for gas entering the burner and guides the gas to the boiler furnace; a plurality of premixed gas guide pipes 3 are uniformly arranged at the top of the premixed gas inlet pipe 2 in a circumferential direction; each premixed gas guide pipe 3 is connected with the premixed gas inlet pipe 2 arranged in the air guide cylinder 1 and the air staging guide cylinder 5; a plurality of premixed gas injection holes 4 are uniformly arranged on the premixed gas guide pipe 3; a primary mixed gas center outlet 9 is arranged at the end of the air staging guide cylinder 5 away from the premixed gas inlet pipe 2; a mixed gas contraction section 16 and a mixed gas guide cylinder 17 are coaxially arranged at the end of the air guide cylinder 1 in sequence; the mixed gas contraction section 16 is a contraction port, the hole diameter of the end of the mixed gas contraction section 16 connected with the air guide cylinder 1 is consistent with the hole diameter of the air guide cylinder 1, the hole diameter of the end of the mixed gas contraction section 16 connected with the mixed gas guide cylinder 17 is consistent with the hole diameter of the mixed gas guide cylinder 17, and the hole diameter of the air guide cylinder 1 is larger than the hole diameter of the mixed gas guide cylinder 17; a plurality of mixed gas injection holes 18 are uniformly arranged on the end face of the end of the mixed gas guide cylinder 17 away from the air guide cylinder 1; a secondary mixed area 22 is formed between the premixed gas guide pipe 3, the inner wall of the air guide cylinder 1 and the outer wall of the air staging guide cylinder 5, and a primary mixed area 23 is formed between the premixed gas guide pipe 3 and the inner wall of the air staging guide cylinder 5.

[0034] The air guide cylinder 1 is sleeved with an ejector gas ring cavity 11; the air guide cylinder 1 is provided with an ejector gas inlet pipe 10; the ejector gas ring cavity 11 is connected with the ejector gas inlet pipe 10, the ejector gas ring cavity 11 is uniformly provided with a plurality of ejector gas guide pipes 12 at the end; the ejector gas guide pipes 12 are coaxially provided with an ejector contraction section 13, an ejector gas injection hole 14 and an ejector mixing section 15 in sequence at the end; the ejector contraction section 13 is a contraction port, the hole diameter of the end of the ejector contraction section 13 close to the ejector gas guide pipe 12 is greater than the hole diameter of the end of the ejector contraction section 13 close to the ejector gas injection hole 14; the ejector gas injection hole 14 and the ejector mixing section 15 form a gas and flue gas mixing area 24; the ejector gas injection hole 14 and the ejector mixing section 15 are separately coaxially installed; one flue gas entrainment structure 21 is arranged between every two ejector mixing sections 15; the flue gas entrainment structure 21 and the mixed gas guide cylinder 17 form a mixed gas and flue gas mixing area 25.

[0035] In use, the gas is divided into two parts, the first part flows into the premix gas guide pipe 3 from the premix gas inlet pipe 2, is sprayed out from the premix gas injection hole 4, the gas sprayed out from the premix gas injection hole 4 located in the primary mixing area 23 is mixed with the primary air, and the primary mixed gas is formed in the primary mixing area 23, flows out from the primary mixed gas center outlet 9, the gas sprayed out from the premix gas injection hole 4 located in the secondary mixing area 22 is mixed with the secondary air, and the secondary mixed gas is formed in the secondary mixing area 22; the mixed gas continues to flow to the burner head, is mixed with the primary mixed gas flowing out from the primary mixed gas center outlet 9 to form the final mixed gas, passes through the mixed gas contraction section 16 and the mixed gas guide cylinder 17 in sequence, and is finally sprayed out from the mixed gas injection hole 18; due to the large gas flow rate, a low pressure area is formed in the mixed gas and flue gas mixing area 25, part of the flue gas is entrained to the mixed gas and flue gas mixing area 25 under the action of the flue gas entrainment structure 21, is mixed with the mixed gas sprayed out from the mixed gas injection hole 18, the effect of reducing the flue gas concentration is achieved, the generation of NOx is reduced, a center premix flame is formed at the end of the mixed gas injection hole 18, the air amount in this area is relatively large, oxygen-rich combustion is formed, a low-nitrogen oxygen-rich combustion atmosphere is formed in the center area due to the premix combustion; the second part of the gas enters the ejector gas inlet pipe 10, flows through the ejector gas ring cavity 11, the ejector gas guide pipe 12, the ejector contraction section 13 in sequence, and is finally sprayed out from the ejector gas injection hole 14; due to the large gas flow rate, a low pressure area is formed in the gas and flue gas mixing area 24, part of the flue gas is entrained to the gas and flue gas mixing area 24 under the action of the ejector mixing section 15, is mixed with the gas sprayed out from the ejector gas injection hole 14, the oxygen concentration in the mixed gas is reduced, the flame temperature and NOx are further reduced, and the gas is sprayed out at the end of the ejector mixing section 15 to form an outer peripheral diffusion flame area; and the excess center air is mixed with the outer peripheral mixed gas to assist combustion.

[0036] Due to the premixing and double-ejection, the premixed flame is formed, complete combustion under the optimal excess air coefficient is realized, the amount of nitrogen oxide generated is very low, and each combustion area generates mixing effect and shearing effect under the action of multiple staging, and intense material and heat transfer is carried out, so that stable and efficient combustion area is formed.

[0037] In some embodiments, the end of the air guide cylinder 1 is provided with a mounting flange 19, and a plurality of screw holes 20 are uniformly distributed on the mounting flange 19, which are used for mounting and fixing the burner in the boiler furnace, so that the burner is convenient to install, disassemble and overhaul.

[0038] In some embodiments, the flue gas entrainment structure 21 is an arc-shaped baffle, and the flue gas entrainment structure is coaxially arranged with the mixed gas guide cylinder 17; in this way, the flue gas entering the mixed gas flue gas mixing area 25 through ejection is mixed with the fuel gas sprayed by the ejection fuel gas injection hole 14 more uniformly.

[0039] In some embodiments, the air staging guide cylinder 5 is provided with a plurality of first mixed gas swirl vanes 7 and a plurality of first mixed gas swirl outlets 8 which are uniformly distributed on the circumference of the end of the air staging guide cylinder 5 away from the premixed fuel gas inlet pipe 2; a plurality of second mixed gas swirl vanes 6 are arranged between the premixed fuel gas guide pipe 3 and the first mixed gas swirl vane 7; and the plurality of second mixed gas swirl vanes 6 are uniformly distributed on the outside of the air staging guide cylinder 5.

[0040] In some embodiments, the premixed fuel gas guide pipe 3 is 3-8 in number; the first mixed gas swirl vane 7 is 6-36 in number; the second mixed gas swirl vane 6 is 6-36 in number; the ejection fuel gas guide pipe 12 is 4-18 in number; the ejection mixing section 15 is 4-18 in number; and the flue gas entrainment structure 21 is 4-18 in number; in this way, the mixing of air and fuel gas is further strengthened, the mixing is more uniform, the combustion efficiency is improved, and the generation of nitrogen oxide is reduced.

[0041] The double-ejection low-nitrogen burner provided by the present application is described in detail above. The description of the specific embodiments is only used to help understand the method of the present application and its core idea. It should be noted that, for those skilled in the art, without departing from the principle of the present application, some improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A dual-ejector low-NOx burner, applied in a boiler furnace, characterized in that: The burner includes an air guide tube (1), a premixed gas inlet pipe (2), and an air stage guide tube (5); the air guide tube (1) and the air stage guide tube (5) are coaxially arranged; multiple premixed gas guide tubes (3) are evenly arranged around the top of the premixed gas inlet pipe (2); multiple premixed gas nozzles (4) are evenly arranged on the premixed gas guide tubes (3); a primary mixed gas center outlet (9) is provided at the end of the air stage guide tube (5) away from the premixed gas inlet pipe (2); a mixed gas contraction section (16) and a mixed gas guide tube (17) are coaxially arranged at the end of the air guide tube (1); multiple mixed gas nozzles (18) are evenly arranged on the end face of the mixed gas guide tube (17) away from the air guide tube (1). An ejector gas ring cavity (11) is sleeved on the outside of the air guide tube (1); an ejector gas inlet pipe (10) is provided on the air guide tube (1); the ejector gas ring cavity (11) is connected to the ejector gas inlet pipe (10), and multiple ejector gas guide tubes (12) are evenly arranged at the end of the ejector gas ring cavity (11); an ejector converging section (13), an ejector gas nozzle (14), and an ejector mixing section (15) are arranged coaxially at the end of the ejector gas guide tube (12); the ejector gas nozzle (14) and the ejector mixing section (15) are installed separately and coaxially; a flue gas entrainment structure (21) is provided between every two ejector mixing sections (15). The smoke entrainment structure (21) is an arc-shaped baffle; The air grading guide tube (5) has multiple primary mixing cyclone vanes (7) and multiple primary mixing cyclone outlets (8) evenly distributed around the end away from the premixed gas inlet pipe (2). Multiple secondary mixing cyclone vanes (6) are provided between the premixed gas guide pipe (3) and the primary mixing cyclone vane (7); the multiple secondary mixing cyclone vanes (6) are evenly distributed circumferentially on the outside of the air grading guide tube (5).

2. The dual-ejector low-NOx burner according to claim 1, characterized in that: The number of premixed gas guide pipes (3) is 3 to 8.

3. A dual-ejector low-NOx burner according to claim 2, characterized in that: The number of primary mixing cyclone vanes (7) is 6 to 36.

4. A dual-ejector low-NOx burner according to claim 3, characterized in that: The number of secondary mixing cyclone vanes (6) is 6 to 36.

5. A dual-ejector low-NOx burner according to claim 4, characterized in that: The number of ejector gas guide pipes (12) is 4 to 18.

6. A dual-ejector low-NOx burner according to claim 5, characterized in that: The ejector mixing section (15) consists of 4 to 18 segments.

7. A dual-ejector low-NOx burner according to claim 6, characterized in that: The number of smoke entrainment structures (21) is 4 to 18.

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