An ultra-short flame burner for a top combustion hot blast stove

Abstract

The utility model relates to a super short flame combustor for top combustion type hot blast stove, can effectively solve the problem of the combustion period dome dead zone CO concentration high resulting in combustion explosion phenomenon, further resulting in dome damage and gas nozzle damage, its solved technical scheme is, the combustor body is by the arc wall body of vault lower part and the straight section wall body connected in vault lower part constitutes, is provided with gas entrance on the outer side wall of straight section wall body, is equipped with gas ring road in the straight section wall body corresponding to gas entrance, and the gas ring road is linked together with the mixed combustion spout of corresponding straight section wall body inner wall on several rows along the circumference and is set up, is provided with air inlet on the outer side wall of arc wall body of vault lower part, the utility model cuts the gas and air fully and subdivides, adopts the mixed spout in the burner and ignites and burns, and the dome area CO of combustion period is lower than 1.5 ten thousand PPM, far lower than the gas and air mixed ignition concentration, can effectively eliminate the existence of deflagration, is the innovation on the combustor.

Description

I. Technical Field

[0001] This utility model relates to hot blast stove burners, and in particular to an ultra-short flame burner for a top-fired hot blast stove. II. Background Technology

[0002] Top-fired hot blast stoves in my country exhibit diverse characteristics, but they basically fall into two structural forms. One is the Kalugin-style pre-combustion chamber with gas nozzles at the top and air nozzles at the bottom, a premixed configuration. Regardless of structural variations, this type of stove remains within the Kalugin framework and exhibits the high deflagration characteristics of the dome dead zone CO concentration. Although this type of stove is less common, there are numerous cases of gas nozzle collapses at the top of the pre-combustion chamber. Mathematical models used in the promotional materials of such stove manufacturers show that the CO concentration in the dome dead zone during combustion reaches as high as 2.2 million PPM. Combined with the structural damage characteristics, this indicates the presence of deflagration in the deflagration medium within the dome dead zone. This design of the combustion device poses a risk of instantaneous explosion and should be optimized and improved to eliminate this hazard and ensure safe, stable, and long-lasting operation.

[0003] The swirl-interlaced top-fired hot blast stove technology, jointly developed and tested by Yuxing, Chongqing University, and China Metallurgical Group Corporation (MCC) in 1350-2500m³ applications at companies such as Shuigang, Dagang, Degang, and Yangang. 3 During the operation of the blast furnace, the characteristics of damage to the combustion deflagration medium in the dome dead zone were also discovered: This hot blast stove is based on the Kalugin hot blast stove structure, and a mixed combustion technology of alternating gas and air swirls was added between the upper gas vent and the lower air vent in the pre-combustion chamber. The middle vent is an alternating gas and air vent, the lower vent is an air vent, and the upper vent is a gas vent. From the dissected photographs of the pre-combustion chamber during use, the gas nozzles of the alternating vents and the air vent nozzles were completely undamaged, but all the upper gas nozzles were damaged, further confirming the existence of deflagration of high-concentration CO in the dome dead zone. The numerical model calculations commissioned by China Metallurgical Group Corporation (MCC) from a professional department of Chongqing University showed that the CO concentration at the dome during the combustion period was 2.01 million PPM. This provided the conditions for the instantaneous explosion during the transition between combustion and air supply.

[0004] Although the aforementioned structures all utilize high-end products with a patented 1100℃ water-cooled, 100-cycle thermal shock resistant process designed and used by Kalugin Company under license from Yuxing, high-end materials alone are insufficient to address the root cause of the problem. Only by fundamentally eliminating the high concentrations of CO and air filling the dead zone of the pre-combustion chamber can deflagration be prevented. Nitrogen purging cannot reach the dead zone where the gas and air become inert gases and completely destroy the combustion; nitrogen purging only purges residual gas and high-temperature air in the ring and nozzle areas. The damage to the pre-combustion chamber burner is due to an inherent technical defect in the designed mixed combustion structure, which has strong detonation capabilities. Since 2005, Yuxing has cumulatively repaired and renovated 550m sections of Qinggang Steel. 3 4747m to Angang 3The damage rate of the gas burners in the pre-combustion chamber of the more than 150 small-cap top-fired hot blast stoves of the blast furnace is as high as 100%.

[0005] The Kalugin top-fired hot blast stove was introduced to my country in 2002. Due to its high blast temperature, small footprint, and low investment, it has become the mainstream equipment configuration for blast furnaces in my country, with relatively few problems. Based on extensive past production practice, the Kalugin top-fired hot blast stove has three common defects that urgently need optimization and improvement: "furnace shell cracking, pre-combustion chamber collapse (100%), and high temperature and collapse at the hot blast outlet (90%)". These defects have a significant impact on energy saving and high blast temperature.

[0006] The damage can be caused by two main factors: 1. Backfire and detonation damage due to insufficient nitrogen purging; 2. Detonation caused by a large amount of carbon monoxide and oxygen-containing air filling the dead zone of the pre-combustion chamber dome; 3. Poor quality of pre-combustion chamber materials; 4. The impact of large temperature differences between the combustion chamber and the pre-combustion chamber on the structure. The gas and air are stratified and premixed in a swirling combustion process, resulting in backfire and explosion damage in the annular channel due to insufficient nitrogen purging, and detonation caused by a large amount of carbon monoxide and high-temperature air filling the dome. Whether it's a backfire explosion or detonation due to CO filling the dead zone of the dome, the probability of burner nozzle damage is 100%, while the air nozzles remain 100% intact. Therefore, the improvement and innovation of burners used in top-fired hot blast stoves is an urgent problem to be solved. III. Utility Model Content

[0007] In view of the above situation and to overcome the shortcomings of the existing technology, the purpose of this utility model is to provide an ultra-short flame burner for a top-fired hot blast stove. Theoretical research, numerical simulation calculation and practical verification were carried out on premixed long flame swirl combustion technology and ultra-short flame non-detonation combustion technology. It can effectively solve the problem of combustion explosion caused by high CO concentration in the dome dead zone during the combustion period, which further leads to dome damage and gas nozzle damage.

[0008] This invention, through various hot blast stove hybrid combustion technologies, numerical simulation calculations, and practical verification, concludes that top-fired hot blast stoves employing premixed combustion exhibit a technical characteristic of instantaneous explosion damaging the burner during the transition between combustion and air supply. This is not causally related to nitrogen purging of residual coal gas at the annulus, burner, or nozzle. Therefore, only by fully considering that the dome cannot be filled with high-concentration CO gas during the combustion period when designing the hot blast stove burner structure can the explosion phenomenon be eliminated, and the stable and long-lasting pre-combustion chamber structure be synchronized with the lifespan of the hot blast stove. Accordingly, the technical solution of this utility model to solve the above problems includes a burner body, which is composed of an arc-shaped wall at the bottom of the arch and a straight section wall connected to the bottom of the arch. A gas inlet is provided on the outer wall of the straight section wall, and a gas loop is provided in the straight section wall corresponding to the gas inlet. The gas loop is connected to several rows of circumferentially arranged mixing combustion nozzles on the inner wall of the corresponding straight section wall via a gas passage. An air inlet is provided on the outer wall of the arc-shaped wall at the bottom of the arch, and an air loop is provided in the arc-shaped wall corresponding to the air inlet. The air loop is connected to the circumferentially arranged air nozzles on the inner wall of the corresponding arc-shaped wall, and the air loop is connected to the mixing combustion nozzles via an air passage provided in the straight section wall.

[0009] Furthermore, the air passage and the gas passage are intersected within the straight section of the wall, with the air passage located inside the gas passage.

[0010] Furthermore, the mixing combustion nozzles are arranged in four rows, one above the other. The first row of mixing combustion nozzles is a direct injection hole perpendicular to the central axis of the burner. The second row of mixing combustion nozzles is a nozzle with a 5-10° tangential angle to the central axis. The third row of mixing combustion nozzles is a nozzle with a 15-20° tangential angle to the central axis. The fourth row of mixing combustion nozzles is a nozzle with a 25-30° tangential angle to the central axis.

[0011] Furthermore, the aforementioned rows of mixed combustion nozzles are arranged in a progressively staggered manner, with the mixed combustion nozzles in the same row being evenly spaced laterally, and the mixed combustion nozzles in different rows being evenly spaced longitudinally.

[0012] Furthermore, the three gas passages corresponding to the gas inlet are sealed with fireproof sealing materials.

[0013] Furthermore, both the gas ring channel and the air ring channel are arranged circumferentially along the burner body.

[0014] Furthermore, the height of both the gas ring channel and the air ring channel is greater than their width.

[0015] Furthermore, the air nozzle forms an angle of 30-60° with the central axis of the burner body.

[0016] The beneficial technical effects of this utility model are as follows:

[0017] 1) Place the gas nozzle in the lower part of the pre-combustion chamber and the air nozzle in the upper part. When the air valve is opened, the pressurized air swirls downwards. Since the upper dome chamber's dead zone is not filled with a high concentration of gas, no deflagration will occur. The upper dome chamber is filled entirely with air, which swirls downwards. When the gas valve is opened, the gas is compressed and swirls and mixes while burning.

[0018] 2) The gas and air are fully cut and subdivided, and multi-burner multi-layer multi-angle mixing and combustion are carried out. The mixture is sprayed out in the burner and then ignited. During the combustion period, the CO in the dome area is less than 15,000 PPM, eliminating the existence of deflagration. At the same time, the flue gas flow field is adjusted to be uniform. An additional row of air injection holes is added in the dome dead zone. During the mixed combustion, a certain concentration of CO flowing to the dome dead zone is burned off simultaneously, ensuring that the CO concentration in this area is lower than the mixed combustion ignition concentration to avoid deflagration and ensure the stability and longevity of the combustion chamber structure. IV. Description of the attached drawings

[0019] Figure 1 This is a front view of the structural cross-section of this utility model.

[0020] Figure 2 This utility model Figure 1 Schematic diagram of section 1-1.

[0021] Figure 3 This utility model Figure 1 Schematic diagram of section 2-2.

[0022] Figure 4 This utility model Figure 1 Schematic diagram of section 3-3.

[0023] Figure 5 This utility model Figure 1 Schematic diagram of section 4-4.

[0024] Figure 6 This utility model Figure 1 Schematic diagram of section 5-5.

[0025] Figure 7 This utility model Figure 1 Schematic diagram of section 6-6.

[0026] Figure 8 This utility model Figure 1 Schematic diagram of section 7-7.

[0027] In the attached diagram, the components are: burner body 1, gas inlet 2, air inlet 3, gas loop 4, air passage 5, mixed combustion nozzle 6, fourth row of mixed combustion nozzles 6a, third row of mixed combustion nozzles 6b, second row of mixed combustion nozzles 6c, first row of mixed combustion nozzles 6d, air loop 7, air nozzle 8, and gas passage 9. V. Detailed Implementation Methods

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] Reference Figure 1-8 This utility model includes a burner body 1, which is composed of an arc-shaped wall at the bottom of the arch and a straight section wall connected to the bottom of the arch. A gas inlet 2 is provided on the outer wall of the straight section wall, and a gas ring channel 4 is provided in the straight section wall corresponding to the gas inlet 2. The gas ring channel 4 is connected to several rows of circumferentially arranged mixing combustion nozzles 6 on the inner wall of the corresponding straight section wall via a gas passage 9. An air inlet 3 is provided on the outer wall of the arc-shaped wall at the bottom of the arch, and an air ring channel 7 is provided in the arc-shaped wall corresponding to the air inlet 3. The air ring channel 7 is connected to the circumferentially arranged air nozzles 8 on the inner wall of the corresponding arc-shaped wall, and the air ring channel 7 is connected to the mixing combustion nozzles 6 via an air passage 5 provided in the straight section wall.

[0030] Furthermore, the air passage 5 and the gas passage 9 are intersected within the straight section of the wall, with the air passage 5 located inside the gas passage 9.

[0031] Furthermore, the mixing combustion nozzle 6 is provided with four rows, one above the other. The first row of mixing combustion nozzles 6d is a direct injection hole perpendicular to the central axis of the burner. The second row of mixing combustion nozzles 6c is a nozzle with a 5-10° tangential angle to the central axis. The third row of mixing combustion nozzles 6b is a nozzle with a 15-20° tangential angle to the central axis. The fourth row of mixing combustion nozzles 6a is a nozzle with a 25-30° tangential angle to the central axis.

[0032] Furthermore, the plurality of rows of mixed combustion nozzles 6 are arranged in a progressively staggered manner, with the mixed combustion nozzles 6 in the same row being evenly spaced laterally and the mixed combustion nozzles 6 in different rows being evenly spaced longitudinally.

[0033] Furthermore, the three gas channels 9 corresponding to the gas inlet 2 are sealed with fireproof sealing materials.

[0034] Furthermore, the gas ring channel 4 and the air ring channel 7 are both arranged circumferentially along the burner body 1.

[0035] Furthermore, the height of both the gas ring channel 4 and the air ring channel 7 is greater than their width.

[0036] Furthermore, the air nozzle 8 forms an angle of 30-60° with the central axis of the burner body.

[0037] This invention, through research and theoretical analysis of burner structural damage caused by burner deflagration in the actual production of top-tier international top-fired hot blast stoves, concludes that the damage is due to defects in the stratified premixed combustion technology with gas on top and air below. While normal nitrogen purging can prevent backfire damage to the gas loop and gas inlet, this setup creates dead zones that nitrogen purging cannot reach, including the high concentration of carbon monoxide in the dome dead zone during combustion and the high concentration of oxygen in the dome dead zone during air supply. This results in unavoidable deflagration and detonation, which is the main factor damaging the burner.

[0038] Based on this, the proposed burner structure features 80-100 small burners in multiple layers and angles for air and gas mixing. This effectively reduces knocking. The four rows of mixing combustion nozzles, arranged with different swirl angles, gradually change from the vertical central axis to 25-30°, guiding the gas and air to form multi-layered rotating airflow, significantly increasing their contact area and mixing path. Simultaneously, the progressive staggered arrangement ensures equidistant horizontal spacing between nozzles in the same row and equidistant vertical spacing between nozzles in different rows, preventing airflow interference and resulting in more uniform mixing. This effectively improves combustion efficiency and reduces energy waste from incomplete combustion. The air nozzle forms a 30-60° angle with the burner body's central axis. Combined with the multi-angle design of the mixing combustion nozzles, combustion stability and flame shape control are significantly optimized. The layout, where the air and gas channels intersect within the straight section wall with the air channel located on the inner side, allows for faster initial mixing of air and gas near the nozzle, providing favorable conditions for stable combustion and reducing the risk of flame pulsation or flameout.

[0039] The three gas passages corresponding to the gas inlet are sealed with fire-resistant sealing material, which can effectively prevent flames or high-temperature flue gas from backflowing into the gas loop, reducing the probability of safety accidents caused by gas leakage or backfire. The gas loop and air loop are set along the circumference of the burner body, and the height is greater than the width, which not only ensures the uniform distribution of gas and air, but also enhances the stability of the loop structure and reduces the risk of loop damage caused by pressure fluctuations.

[0040] The air circulation channel connects to the mixing and combustion nozzles through air passages within the straight section wall, enabling multi-path air delivery. This ensures sufficient air supply while simplifying the internal piping layout, facilitating installation and maintenance. Furthermore, the circumferential arrangement and equidistant layout of all components ensure uniform stress distribution across the burner, extending its service life and making it suitable for long-term, high-intensity industrial combustion scenarios.

[0041] In addition to ensuring nitrogen purging of the gas inlet of the ring channel and burner to prevent backfire damage, although there is still a certain concentration of CO in the dome dead zone, a special single-row combustion air injection system is installed to eliminate carbon monoxide and consume the CO in the dead zone, thus completely eliminating the risk of deflagration in this area. Through theoretical research and mathematical model calculations commissioned from the Cheng Shusen research group at Beijing University of Science and Technology, and verification through the combination of theory and practice in multiple project constructions, this utility model has the advantages of ultra-short flame, effective regulation of flue gas flow field, significant reduction of CO and NOx in flue gas, stable structure, and small wind-temperature difference.

[0042] Through Nanjing Steel No. 1 2000m 3 The practice of converting the No. 1 hot blast stove of the blast furnace from a Kalugin top-fired hot blast stove to an ultra-short flame combustion technology yielded the following online test conclusions: carbon monoxide emissions can be controlled at 10 PPM, and NOx emissions are below 61 mg / m³. 3 The small temperature distribution difference on the bed surface of the regenerator significantly improves the air temperature. Practical data and theoretical calculations are in good agreement, comprehensively reflecting the superior characteristics of this combustion technology. In particular, the ultra-low amount of nitrogen oxides generated in the hot blast stove lays a solid foundation for the development of large-scale, high-temperature hot blast stoves.

[0043] This novel ultra-short flame burner is applied to a top-fired hot blast stove. A parameter comparison with the existing Kalugin top-fired hot blast stove is as follows:

[0044] Table 1. Comparison of Kalugin top-fired hot blast stove and ultra-short flame burner applications in top-fired hot blast stoves.

[0045]

[0046]

[0047] This utility model features a multi-layer, multi-burner, multi-angle column flow plus swirl ultra-short flame burner that thoroughly cuts and subdivides coal gas and air. The gas and air are mixed and injected within the burner before ignition. During combustion, the CO concentration in the dome area is below 15,000 PPM, far lower than the ignition concentration of the mixed coal gas and air, effectively eliminating deflagration. An additional row of air injection holes is added to the dome dead zone, simultaneously burning off a certain concentration of CO flowing into the dome dead zone during mixed combustion. Based on structural improvements, the upper dome dead zone is not filled with high-concentration coal gas, thus preventing deflagration. It also regulates the uniform distribution of the flue gas flow field, ensuring the stability and longevity of the combustion chamber structure. This innovative burner offers significant economic and social benefits.

Claims

1. An ultra-short flame burner for a top-fired hot blast stove, comprising a burner body, characterized in that, The burner body (1) is composed of an arc-shaped wall at the bottom of the arch and a straight wall connected to the bottom of the arch. A gas inlet (2) is provided on the outer wall of the straight wall. A gas loop (4) is provided in the straight wall corresponding to the gas inlet (2). The gas loop (4) is connected to several rows of circumferentially arranged mixing combustion nozzles (6) on the inner wall of the corresponding straight wall via a gas passage (9). An air inlet (3) is provided on the outer wall of the arc-shaped wall at the bottom of the arch. An air loop (7) is provided in the arc-shaped wall corresponding to the air inlet (3). The air loop (7) is connected to the circumferentially arranged air nozzles (8) on the inner wall of the corresponding arc-shaped wall. The air loop (7) is connected to the mixing combustion nozzles (6) via an air passage (5) provided in the straight wall.

2. The ultra-short flame burner for a top-fired hot blast stove according to claim 1, characterized in that, The air passage (5) and the gas passage (9) are intersected in the straight section wall, and the air passage (5) is located inside the gas passage (9).

3. The ultra-short flame burner for a top-fired hot blast stove according to claim 1, characterized in that, The mixing combustion nozzle (6) is provided with four rows, one above the other. The first row of mixing combustion nozzles (6d) is a direct injection hole perpendicular to the central axis of the burner. The second row of mixing combustion nozzles (6c) is a nozzle with a 5-10° tangential angle to the central axis. The third row of mixing combustion nozzles (6b) is a nozzle with a 15-20° tangential angle to the central axis. The fourth row of mixing combustion nozzles (6a) is a nozzle with a 25-30° tangential angle to the central axis.

4. The ultra-short flame burner for a top-fired hot blast stove according to claim 1, characterized in that, The aforementioned rows of mixed combustion nozzles (6) are arranged in a progressively staggered manner. The mixed combustion nozzles (6) in the same row are evenly spaced laterally, and the mixed combustion nozzles (6) in different rows are evenly spaced longitudinally.

5. The ultra-short flame burner for a top-fired hot blast stove according to claim 1, characterized in that, The three gas channels (9) corresponding to the gas inlet (2) are sealed with fireproof sealing material.

6. The ultra-short flame burner for a top-fired hot blast stove according to claim 1, characterized in that, The gas ring channel (4) and air ring channel (7) are both arranged around the burner body (1).

7. The ultra-short flame burner for a top-fired hot blast stove according to claim 1, characterized in that, The height of the gas ring (4) and the air ring (7) is greater than their width.

8. The ultra-short flame burner for a top-fired hot blast stove according to claim 1, characterized in that, The air nozzle (8) is at an angle of 30-60° to the central axis of the burner body.

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