Low-nitrogen regenerative flat flame burner adopting hierarchical structure

Abstract

The application is implemented by the following technical scheme: a low-nitrogen type regenerative flat flame burner adopting a hierarchical structure, comprising a regenerator chamber, a pre-chamber for guiding air is arranged in the regenerator chamber, a gas delivery pipeline for gas into the pre-chamber and for gas out of the discharge end of the regenerator chamber is arranged on the regenerator chamber, a first flow guide for guiding air is arranged on the inner wall of the discharge end of the regenerator chamber, and a second flow guide is arranged on the gas delivery pipeline on the side of the discharge end of the regenerator chamber. The application has the advantages that the air passage in the burner is designed into three parts of primary air, secondary air and tertiary air by using the air staging and nitrogen reduction principle, the gas passage in the burner is designed into three parts of primary gas, secondary gas and tertiary gas, the nitrogen oxide emission value in the flue gas can be reduced to below 100 mg / m3, and the burner has the energy-saving effect and the ultra-low nitrogen oxide emission effect of the conventional regenerative heating furnace.

Description

Technical Field

[0001] This invention relates to the field of burner technology, specifically to a low-NOx regenerative flat flame burner with a staged structure. Background Technology

[0002] Currently, most domestic ferrous metallurgy and machinery industries use regenerative burners and matching combustion systems to heat the furnace, which can greatly save fuel consumption. These are relatively mature and practical energy-saving products both domestically and internationally.

[0003] Regenerative burners and related combustion systems are widely and maturely applied in heating furnaces in the ferrous metallurgy and machinery industries due to their energy-saving effect of more than 30%. The preheated air temperature reaches more than 800°C, and when it mixes with the fuel injection, it produces a violent combustion reaction. The flame temperature is high and concentrated, and the temperature gradient distribution of the flame is very obvious. Therefore, the nitrogen oxides produced by combustion are very high, usually between 200 and 800 milligrams per cubic meter of flue gas.

[0004] With the increasing emphasis placed on NOx emissions from industrial furnaces and kilns by national and local governments, increasingly stringent emission standards have been set. As a result, many low-NOx regenerative burners with a primary stage structure have appeared on the market. These burners are characterized by using a single air stage or a single gas stage structure, with NOx emissions ranging from 150 to 200 mg.

[0005] With further restrictions on nitrogen oxide emissions in the market, traditional low-NOx regenerative burners are finding it difficult to control nitrogen oxide emissions below 100 milligrams. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a low-NOx regenerative flat flame burner with a staged structure, which reduces NOx emissions in flue gas to below 100 mg / m³, achieving both the energy-saving effect and ultra-low NOx emission effect of conventional regenerative heating furnace burners.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The present invention is achieved through the following technical solution: a low-NOx regenerative flat flame burner with a staged structure, comprising a regenerative chamber, a pre-combustion chamber for guiding air in the regenerative chamber, a gas delivery pipe for the regenerative chamber leading to the gas inside the pre-combustion chamber and the gas leading to the gas outlet of the regenerative chamber, a first air guide on the inner wall of the gas outlet of the regenerative chamber, and a second air guide on the gas delivery pipe located on the side of the gas outlet of the regenerative chamber;

[0009] The second guide includes a frustum-shaped fixing ring and a first channel. The large-diameter end of the frustum-shaped fixing ring is located on one side of the heat storage chamber discharge end, and an inclined first channel is formed in the frustum-shaped fixing ring.

[0010] The gas delivery pipeline is connected to a primary gas spray gun leading to the pre-combustion chamber, and the gas delivery pipeline is connected to a secondary gas spray gun leading to the outlet of the heat storage chamber.

[0011] Preferably, a second channel is formed between the frustum-shaped fixing ring and the secondary gas spray gun.

[0012] Preferably, the end of the secondary gas spray gun is provided with a secondary gas nozzle that leads the gas to the second channel, and the end of the secondary gas spray gun is provided with a tertiary gas nozzle that leads the gas to the outside of the heat storage room.

[0013] Preferably, the first guide member is a circular ring structure, the inner wall of the first guide member is inclined, and the outer walls of the first guide member and the second guide member are parallel.

[0014] Preferably, the outer wall of the secondary gas spray gun is covered with a high-temperature resistant layer.

[0015] Preferably, the pre-combustion chamber is a cylindrical hollow structure, and the pre-combustion chamber is provided with a plurality of inclined through holes evenly distributed on the pre-combustion chamber. The heat storage chamber is provided with an ignition gun that penetrates into the interior of the pre-combustion chamber.

[0016] Preferably, the burner bricks are mounted on the outer wall of the heat storage chamber discharge end, and the burner bricks are arranged in a trumpet shape on the heat storage chamber.

[0017] Preferably, the heat storage chamber has a ceramic honeycomb structure and a baffle brick arranged sequentially inside the input end, and the heat storage chamber is equipped with refractory bricks inside.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] By using the principle of air-stage nitrogen reduction, the air passage inside the burner is designed to be divided into three parts: primary air, secondary air, and tertiary air. Similarly, the gas passage inside the burner is designed to be divided into three parts: primary gas, secondary gas, and tertiary gas. This can reduce the nitrogen oxide emission value in the flue gas to below 100 mg / m³, achieving the energy-saving effect and ultra-low nitrogen oxide emission effect of conventional regenerative heating furnace burners. Attached Figure Description

[0020] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts. Wherein:

[0021] Figure 1 This is a schematic diagram of the structure of the flat flame burner of the present invention;

[0022] Figure 2 This is a partial enlarged view of part A of the flat flame burner of the present invention;

[0023] Figure 3 This is a schematic diagram of the air circulation inside the heat storage chamber of the present invention;

[0024] Figure 4 This is a schematic diagram of gas flow according to the present invention.

[0025] The diagram shows the following labels: 1. Air inlet; 2. Heat storage chamber; 3. Ceramic honeycomb structure; 4. Baffle brick; 5. Ignition gun; 6. Gas delivery pipeline; 7. Primary gas spray gun; 8. Secondary gas spray gun; 81. Secondary gas nozzle; 82. Tertiary gas nozzle; 83. High-temperature resistant layer; 9. Pre-combustion chamber; 10. First guide component; 11. Second guide component; 111. Frustum-shaped fixing ring; 112. First channel; 113. Second channel; 12. Burner brick. Detailed Implementation

[0026] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0027] like Figure 1 As shown, a low-NOx regenerative flat flame burner with a staged structure according to the present invention includes a regenerator chamber 2, a pre-combustion chamber 9 for guiding air in the regenerator chamber 2, a gas delivery pipe 6 for gas to the inside of the pre-combustion chamber 9 and gas to the outlet end of the regenerator chamber 2, a first air guide 10 for guiding air on the inner wall of the outlet end of the regenerator chamber 2, and a second air guide 11 for the gas delivery pipe 6 located on the side of the outlet end of the regenerator chamber 2.

[0028] The second guide member 11 includes a frustum-shaped fixing ring 111 and a first channel 112. The large diameter end of the frustum-shaped fixing ring 111 is located on the side of the discharge end of the heat storage chamber 2. An inclined first channel 112 is opened in the frustum-shaped fixing ring 111.

[0029] The gas transmission pipeline 6 is connected to a primary gas spray gun 7 leading to the pre-combustion chamber 9, and the gas transmission pipeline 6 is connected to a secondary gas spray gun 8 leading to the discharge end of the heat storage chamber 2.

[0030] Specifically, cold air enters the heat storage chamber 2 through the air inlet 1, passes through the honeycomb pore system in the ceramic honeycomb body 3 and the baffle brick 4, and enters the central channel. The pre-combustion chamber 9 divides the air into primary air and residual air. The primary air enters the pre-combustion chamber 9 and partially mixes with the primary gas sprayed from the primary gas spray gun 7 in the gas delivery pipeline 6. After encountering the ignition gun 5 and generating a continuous flame, it enters the middle position of the central channel. The residual air enters the middle position of the central channel from the outer end of the pre-combustion chamber 9 and mixes with the flue gas generated by the combustion of the primary gas. At this time, the oxygen concentration of the residual air drops to below 18.5%.

[0031] A first guide 10 is designed at the outlet of the central channel of the burner to divide the remaining air into secondary air and tertiary air. The first guide 10 contains a second guide 11. The secondary gas spray gun 8 at the front end divides the secondary gas into secondary gas and tertiary gas through the secondary gas nozzle 81 and the tertiary gas nozzle 82. The secondary air enters the front end through the second guide 11 and mixes with the secondary gas first. The tertiary gas and the tertiary air are finally mixed.

[0032] It adopts a multi-stage structure of air grading (level three or above) and gas grading (level three or above). Through the deep grading structure, the air and gas are mixed more finely in the burner, the reaction is milder, and the combustion temperature distribution is more uniform. Therefore, it can significantly suppress and reduce the local combustion temperature, and greatly reduce the amount of nitrogen oxides generated.

[0033] This method addresses the issue of high NOx emissions associated with conventional regenerative combustion. By employing a deeply optimized staged structure, NOx emissions in flue gas can be reduced to below 100 mg / m³.

[0034] After the burner air enters the central channel, it is split into primary air and residual air. The primary air enters the pre-combustion chamber and mixes with the primary combustion gas. The primary air entering the pre-combustion chamber is extremely excessive in terms of the equivalent ratio of primary air to primary combustion gas. After the primary combustion gas is fully combusted, a combustion-supporting air with a low oxygen concentration is formed in this area. Due to the extreme excess of air, the generation of nitrogen oxides in this area is extremely low.

[0035] After the complete combustion of the primary combustion gas, the flue gas produced mixes with the remaining air to form a mixed gas with an oxygen content of 10-15% as shown in the figure. It travels along the burner axis and reaches the burner outlet. At the outlet, it is divided into secondary air and tertiary air by the distribution plate. The secondary air meets the secondary combustion gas. If there is an excess of secondary combustion gas and an insufficient amount of secondary air, the combustion in this area is oxygen-deficient, forming secondary combustion gas with a lower calorific value. The flue gas produced after combustion continues to mix with the tertiary combustion gas. At the same time, the low-oxygen combustion-supporting air generated by the mixture with the tertiary air and the secondary combustion gas spreads radially along the burner and diffuses and mixes. Finally, it is completely combusted, which delays the heat release process, eliminates the high-temperature flame area, and greatly reduces the amount of nitrogen oxides generated.

[0036] The burner forms two flue gas internal circulation zones in the primary gas combustion zone and the secondary gas combustion zone. In the flue gas internal circulation zone, a stable flame combustion zone and a flue gas mixing zone are formed. The effect of stable mixing is the guarantee for the generation of stable low nitrogen oxides.

[0037] In addition, this structural design, based on the principle of flue gas internal circulation for nitrogen reduction, allows the flue gas generated by primary air and primary combustion gas to be mixed and entrained with secondary air and secondary combustion gas in the burner, and then the flue gas circulation effect is formed by tertiary air and tertiary combustion gas. Combined with deviation from stoichiometric ratio combustion and rich-lean combustion technology, it provides a guarantee for further deep nitrogen reduction.

[0038] like Figure 1 As shown, a second channel 113 is formed between the frustum-shaped fixing ring 111 and the secondary gas injection gun 8, which allows the frustum-shaped fixing ring 111 to deliver air in different directions, thereby performing secondary and tertiary combustion operations on the gas.

[0039] like Figure 2 As shown, the secondary gas nozzle 8 is provided with a secondary gas nozzle 81 at the end of the secondary gas nozzle 8, which leads the gas to the second channel 113. The secondary gas nozzle 8 is provided with a tertiary gas nozzle 82 at the end of the secondary gas nozzle 8, which leads the gas to the outside of the heat storage chamber 2. The gas sprayed from the secondary gas nozzle 81 will mix with the air transported at the first channel 112. The gas sprayed from the tertiary gas nozzle 82 will mix with the air discharged outside the heat storage chamber 2, thereby performing secondary combustion and tertiary combustion operations.

[0040] like Figure 1 As shown, the first guide member 10 has a circular structure with an inclined inner wall and the outer walls of the first guide member 10 and the second guide member 11 are parallel. This structure can make the air delivery smoother and change the air flow direction in the first channel 112. The air in the first channel 112 and the air between the first guide member 10 and the second guide member 11 flow in different directions, which facilitates secondary and tertiary combustion operations.

[0041] The outer wall of the secondary gas spray gun 8 is wrapped with a high-temperature resistant layer 83. By setting the high-temperature resistant layer 83, the secondary gas spray gun 8 can avoid high-temperature damage, thereby increasing the service life of the secondary gas spray gun 8 and improving the gas delivery effect.

[0042] like Figure 1As shown, the pre-combustion chamber 9 is a cylindrical hollow structure with multiple inclined through holes evenly distributed on it. The heat storage chamber 2 is equipped with an ignition gun 5 that penetrates into the pre-combustion chamber 9. With this structure, a pre-combustion chamber is set inside the burner 9, and a portion of the gas starts to burn inside the burner. The resulting flue gas mixes with air, which can effectively reduce the oxygen content of the air and suppress the violent reaction of the gas when it encounters high-temperature air.

[0043] like Figure 1 As shown, burner bricks 12 are mounted on the outer wall of the exhaust end of the regenerator 2. The burner bricks 12 are arranged in a trumpet shape on the regenerator 2. The design concept of the trumpet opening of the traditional burner head is changed, and the trumpet opening is designed in the furnace wall. This can increase the trumpet spreading surface, make the flame flat effect more obvious, and make the combustion temperature distribution more open and uniform, which is conducive to reducing the amount of nitrogen oxides generated.

[0044] like Figure 1 As shown, the heat storage chamber 2 is provided with ceramic honeycomb body 3 and baffle brick 4 in sequence inside the input end. The heat storage chamber 2 is also provided with refractory bricks to improve durability and lifespan.

[0045] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A low-nitrogen regenerative flat flame burner using a hierarchical structure, characterized by: The application relates to a heat storage chamber (2) provided with a precombustion chamber (9) for guiding air, a gas conveying pipeline (6) for conveying gas into the precombustion chamber (9) and discharging gas from the discharge end of the heat storage chamber (2), a first flow guide (10) provided on the inner wall of the discharge end of the heat storage chamber (2) for guiding air, and a second flow guide (11) provided on the gas conveying pipeline (6) at the discharge end of the heat storage chamber (2). The second flow guide (11) comprises a circular truncated cone fixing ring (111) and a first channel (112), the large-diameter end of the circular truncated cone fixing ring (111) is located at the discharge end of the heat storage chamber (2), and the first channel (112) is arranged in the circular truncated cone fixing ring (111) in an inclined mode. The gas conveying pipeline (6) is connected with a primary gas lance (7) leading into the precombustion chamber (9), and the gas conveying pipeline (6) is connected with a secondary gas lance (8) leading into the discharge end of the heat storage chamber (2). The circular truncated cone fixing ring (111) and the secondary gas lance (8) form a second channel (113). The end of the secondary gas lance (8) is provided with a secondary gas nozzle (81) for conveying gas into the second channel (113), and the end of the secondary gas lance (8) is provided with a tertiary gas nozzle (82) for conveying gas outside the heat storage chamber (2). The first flow guide (10) is in a circular ring structure, the inner wall of the first flow guide (10) is arranged in an inclined mode, and the outer walls of the first flow guide (10) and the second flow guide (11) are arranged in parallel. The outer wall of the secondary gas lance (8) is wrapped with a high-temperature-resistant layer (83). The precombustion chamber (9) is in a hollow structure, a plurality of inclined through holes are uniformly arranged on the precombustion chamber (9), and an ignition lance (5) is arranged in the precombustion chamber (9).

2. A low-nitrogen regenerative flat flame burner with a hierarchical structure according to claim 1, characterized in that: A burner brick (12) is arranged on the outer wall of the discharge end of the heat storage chamber (2).

3. A low-nitrogen flat flame regenerative burner with a hierarchical structure according to claim 1, characterized in that: A ceramic honeycomb body (3) and a baffle brick (4) are sequentially arranged in the input end of the heat storage chamber (2), and the heat storage chamber (2) is internally provided with a refractory brick.

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