Internal premixing multi-burner mixed combustion strong rotational flow ultra-low emission hot blast stove

Abstract

The utility model relates to an internal premixing multi-burner mixed combustion strong rotational flow ultra-low emission hot-blast stove, which can further improve the power of the existing top combustion hot-blast stove, reduce the consumption and prolong the service life of the hot-blast stove, and adopts the technical scheme that a combustion chamber consists of an upper vault inner wall and a lower straight section wall inner wall; a hot air outlet communicated with the outside is formed in the side wall of the straight section wall, a coal gas inlet and an air inlet are formed in the outer wall, corresponding to the burner, of the furnace body, the coal gas inlet is communicated with a coal gas loop arranged in the wall of the furnace body, the air inlet is communicated with an air loop arranged in the wall of the furnace body, and the coal gas loop is communicated with a coal gas ascending channel of the burner. The catenary top combustion type hot blast stove is novel and unique in structure, energy-saving and environment-friendly, CO and O2 in the combustion chamber are fully combusted, the power of an existing catenary top combustion type hot blast stove can be further improved, consumption is reduced, the service life of the hot blast stove is prolonged, and the catenary top combustion type hot blast stove is an innovation of the top combustion type hot blast stove.

Description

1. Technical Field

[0001] The utility model relates to a hot blast stove, in particular to an internal premixed multi-burner mixed combustion strong swirl ultra-low emission hot blast stove. 2. Background Technology

[0002] The hot blast furnace is an important auxiliary equipment for blast furnace ironmaking engineering. It is a device that operates periodically with intermittent heating and cooling. The quality of its performance directly affects the normal operation, use efficiency and service life of itself and the blast furnace. The top-fired hot blast furnace has made great progress in recent years due to its advantages such as high combustion intensity, short flame distance, stress tolerance elimination and relatively simple structure. It is widely used in the hot air supply of blast furnaces. However, from the perspective of technical maturity, there are still many areas worthy of technical innovation and research and development. For example, the existing top-fired hot blast furnace has uneven flame combustion, energy waste, environmental pollution, short service life and high cost. Although the top-fired hot blast furnace with application number 202320194190.X (hereinafter referred to as 202320194190.X top-fired hot blast furnace) has been improved, it can be seen from the air inlet cross section after testing that the mixed airflow on the left flows upward along the edge of the combustion chamber, part of the airflow moves upward into the dome, and the other part of the airflow flows toward the center of the combustion chamber and enters the heat storage chamber. The airflow on the right side rises along the edge of the combustion chamber, and after rising to the middle, it moves downward into the heat storage chamber. The movement state at the gas inlet section is not much different from that at the air inlet section. In terms of the overall movement trend, the airflow on the left side can reach the dome, while the airflow on the right side cannot reach the dome, and turns back in the combustion chamber and enters the heat storage chamber, resulting in some mixed airflows not being completely mixed. Fig.11 The middle arrow represents the direction of movement, and the color represents the speed. On the air inlet section, the mixed airflow from the mixing burner on the left, the downward swirling airflow, directly entering the regenerator has a higher flow rate, and the right airflow directly swirling into the regenerator has a higher flow rate, and the right figure is also the same, so the mixing space and time of this part of the airflow are relatively insufficient, resulting in high CO and O2 concentrations on the combustion outlet interface.

[0003] Since the gas and air burners do not set an angle in the circumferential direction at the mixing nozzle, a swirl cannot be formed in the horizontal section, resulting in uneven velocity distribution on the horizontal section, and disordered velocity distribution on each horizontal section without obvious rules. When the mixed airflow moves to the dome area, the mixed airflow tends to deviate to one side, and the flow velocity on the left side of the dome area is greater than the flow velocity on the right side, so the airflow on the gas inlet side cannot reach the dome.

[0004] Fig.11The highest CO concentration at the combustion chamber outlet section is 91700ppm, and the average concentration is 31800ppm, indicating that most of the CO is not burned, because after the mixed gas enters the combustion chamber from the mixing burner, it directly enters the regenerator obliquely downward, and the mixing space is small, resulting in incomplete combustion; Fig.12 The highest oxygen concentration in this section is 0.106 and the average concentration is 0.0120; based on the oxygen and nitric oxide contents, it can be concluded that CO and O2 are not completely burned and the residual content is high.

[0005] The overall temperature of the combustion chamber is low, but the high temperature area appears in the regenerator, which means that the unburned CO and O2 are not completely burned in the combustion chamber and will continue to burn in the regenerator, which is not conducive to the longevity of the checker bricks. Fig.13 The highest temperature of the combustion chamber outlet section is 1623K, the lowest temperature is 1346K, and the average temperature is 1464K, which means that the temperature of the combustion chamber outlet section is too low to meet the actual needs. Therefore, the improvement and innovation of the top-fired hot blast furnace is a technical problem that needs to be solved urgently. III. Summary of the invention

[0006] In view of the above situation, in order to solve the defects of the prior art, the purpose of the utility model is to provide an internal premixed multi-burner mixed combustion strong swirl ultra-low emission hot air furnace, which can further improve the power of the existing top-fired hot air furnace, reduce consumption, and extend the life of the hot air furnace.

[0007] The technical solution solved by the utility model is to include a furnace body, which is composed of a vault, a combustion chamber, a burner, a heat storage chamber and a cold air chamber at the bottom of the furnace body from top to bottom, the combustion chamber is composed of an upper vault inner wall and a lower straight wall inner wall, a hot air outlet connected to the outside is arranged on the side wall of the straight wall, a gas inlet and an air inlet are arranged on the outer wall of the furnace body corresponding to the burner, the gas inlet is connected to a gas ring channel built into the furnace body wall, the air inlet is connected to an air ring channel built into the furnace body wall, the gas ring channel is connected to a gas rising channel of the burner, the air ring channel is connected to an air rising channel of the burner, the gas rising channel and the air rising channel are alternately arranged, an air branch pipe is arranged at the top of the air rising channel for diversion, a gas branch pipe is arranged at the top of the gas rising channel for diversion, the air branch pipe and the gas branch pipe are both connected to the mixing swirl nozzle through a premixing zone, and a cold air inlet and a smoke outlet connected to the outside of the furnace body are arranged on the cold air chamber.

[0008] The utility model has a novel and unique structural design, and is energy-saving and environmentally friendly. CO and O2 are fully burned in the combustion chamber. Compared with the numerical simulation results of the 202320194190.X top-burning hot blast furnace, the CO and O2 concentrations on the outlet cross-section of the combustion chamber of the top-burning hot blast furnace of the utility model are much lower than those of the 202320194190.X top-burning hot blast furnace, and the outlet temperature of the combustion chamber is high, which can further improve the power of the existing catenary top-burning hot blast furnace, reduce consumption, and extend the life of the hot blast furnace. It is an innovation in the top-burning hot blast furnace and has good economic and social benefits. IV. Description of the drawings

[0009] Figure 1 It is a structural section front view of the utility model.

[0010] Figure 2 It is a schematic diagram of the structural section of the burner of the utility model.

[0011] Figure 3 For this utility model Figure 2 Schematic diagram of the cross-sectional structure of the air ring channel in the AA direction.

[0012] Figure 4 For this utility model Figure 2 A cross-sectional diagram showing the connection between the BB-direction air ring channel and the air rising channel.

[0013] Figure 5 For this utility model Figure 2 Schematic diagram of the cross-sectional structure of the CC air rising channel.

[0014] Figure 6 For this utility model Figure 2 Schematic diagram of the cross-sectional structure of the DD-direction gas ring channel and the gas rising channel.

[0015] Figure 7 For this utility model Figure 2 Schematic diagram of the cross-sectional structure of the EE air rising channel and the gas rising channel.

[0016] Figure 8 For this utility model Figure 2 Schematic diagram of the cross-sectional structure of the FF air branch pipe and the gas branch pipe.

[0017] Fig. 9 For this utility model Figure 2 Schematic diagram of the cross-sectional structure of the GG direction air branch pipe and gas branch pipe mixing channel.

[0018] Fig.10 For this utility model Figure 2 Schematic diagram of the cross-sectional structure of the HH mixing swirl nozzle.

[0019] Fig.11This is the CO concentration distribution diagram of the combustion chamber outlet section of the existing 202320194190.X top-fired hot blast furnace.

[0020] Fig.12 This is the O2 concentration distribution diagram of the combustion chamber outlet section of the existing 202320194190.X top-fired hot blast furnace.

[0021] Fig.13 This is the temperature distribution diagram of the combustion chamber outlet section of the existing 202320194190.X top-fired hot blast furnace.

[0022] Fig.14 This is the CO concentration distribution diagram of the combustion chamber outlet section of the utility model.

[0023] Fig.15 This is the O2 concentration distribution diagram of the combustion chamber outlet section of the utility model.

[0024] Fig.16 This is the temperature distribution diagram of the combustion chamber outlet section of the utility model.

[0025] Fig.17 This is a CO concentration distribution diagram at different cross sections in the furnace body of the utility model.

[0026] Fig.18 This is a diagram of the O2 concentration distribution at different cross sections in the furnace body of the utility model.

[0027] Fig.19 It is the statistical result of O2 mass fraction and CO concentration on the center line of the furnace in the height direction of the utility model.

[0028] Fig. 20 It is a temperature distribution diagram of different cross sections in the combustion chamber of the utility model.

[0029] Fig.21 This is a comparison diagram of the temperature distribution of the combustion chamber outlet section of the utility model and the temperature distribution of the 202320194190.X top-fired hot blast furnace outlet section. V. Specific implementation methods

[0030] The specific implementation of the utility model is further described in detail below with reference to the accompanying drawings.

[0031] Depend on Figure 1-10The utility model includes a furnace body 1, which is composed of a vault 2, a combustion chamber 3, a burner 9, a heat storage chamber 4 and a cold air chamber 13 at the bottom of the furnace body from top to bottom. The combustion chamber 3 is composed of an upper vault inner wall and a lower straight wall inner wall. A hot air outlet 16 connected to the outside is arranged on the side wall of the straight wall. A gas inlet 5 and an air inlet 6 are arranged on the outer wall of the furnace body corresponding to the burner 9. The gas inlet 5 is connected to a gas ring 7 built into the furnace wall, and the air inlet 6 is connected to an air ring 8 built into the furnace wall. The gas ring 7 is connected with the gas rising channel 10 of the burner 9, and the air ring 8 is connected with the air rising channel 11 of the burner 9. The gas rising channel 10 and the air rising channel 11 are arranged alternately. An air branch pipe is arranged at the top of the air rising channel 11 for diversion. A gas branch pipe is arranged at the top of the gas rising channel 10 for diversion. The air branch pipe and the gas branch pipe are connected with the mixing swirl nozzle 12 through the premixing zone. The cold air chamber 13 is provided with a cold air inlet 14 and a smoke outlet 15 connected to the outside of the furnace body 1.

[0032] In order to ensure the use effect, the burner 9 is arranged in a circle around the inner wall of the furnace body 1 and is interconnected. Each burner 9 is composed of a gas rising channel 10 and an air rising channel 11. Two gas branches are arranged at the top of each gas rising channel 10, and two air branches are arranged at the top of each air rising channel 11.

[0033] The number of the mixing swirl nozzles 12 matches the number of the burners 9 .

[0034] The angle between the gas branch pipe and the vertical direction (perpendicular to the horizontal plane) is 10-25°, and the angle between the air branch pipe and the vertical direction is 10-25°.

[0035] The angle between the mixing swirl nozzle 12 and the vertical direction is 10°-25°, and all the mixing swirl nozzles 12 are inclined in the same direction along the circumferential surface.

[0036] The use of the utility model is that the catenary arch structure is adopted, the hot air outlet is arranged above the gas inlet, the angle between the gas branch pipe and the vertical direction, the angle between the air branch pipe and the vertical direction, and the angle between the mixing swirl nozzle 12 and the vertical direction are set, which can make the velocity distribution in the gas and air annular channels uneven, the maximum flow velocity in the gas annular channel is 38.2m / s, the maximum flow velocity in the air annular channel is 18.9m / s, and the highest flow velocity is located near the air gas inlet. The velocity distribution in the air gas annular channel is basically symmetrical along the center line of each inlet. Since the gas rising channel and the air rising channel are provided with a branch pipe in the premixing zone and form an angle with the circumferential direction, the gas in the combustion chamber rotates and flows along the circumferential direction. Since the momentum of the gas is greater than the momentum of the air, the gas will drive the air to rotate and flow along the circumferential direction. In the combustion chamber, the airflow is compressed in the clockwise direction and moves upward, and the swirl intensity is gradually weakened. Previous researchers have performed numerical simulation calculations on swirl burners. Although the air-gas mass flow rate distribution is uneven, the gas is symmetrically distributed along the circumferential direction, which is conducive to air-gas mixing. The angle between the mixing swirl nozzle 12 and the vertical direction is 10°-25°, which provides a premixing area and time for the gas branch pipe and the air branch pipe to fully mix the two and improve combustion efficiency. The overall temperature distribution of the combustion chamber of the utility model is uniform, the lowest temperature at the flame center is 1048K, and the highest temperature in the dome area is 1674K.

[0037] The CO and O2 in the combustion chamber of the utility model burn fully, and compared with the numerical simulation results of the 202320194190.X top-fired hot blast furnace, the CO and O2 concentrations on the outlet section of the combustion chamber of the utility model top-fired hot blast furnace are much lower than those of the 202320194190.X top-fired hot blast furnace, and the outlet temperature of the combustion chamber is higher, which can further improve the power of the existing catenary top-fired hot blast furnace, extend the life of the hot blast furnace, reduce consumption, and extend the life of the hot blast furnace. The relevant numerical simulation results are as follows:

[0038] The structure of the utility model can make the velocity distribution in the gas and air ring channels uneven, the highest velocity in the gas ring channel is 38.2m / s, the highest velocity in the air ring channel is 18.9m / s, and the highest velocity is located near the air gas inlet. The velocity distribution in the air gas ring channel is basically symmetrical along the center line of each inlet.

[0039] The velocity fluctuates greatly at the air ring and the air inlet. When the angle from the air inlet in the furnace is between 10° and 160°, the gas velocity gradually decreases. Near the opposite side of the air ring inlet, the air velocity first decreases and then increases, with the minimum velocity being 0.4 m / s. The air velocity distribution is symmetrical.

[0040] The velocity field of the central section of the air ring is symmetrically distributed along the center line of the air ring. Two airflows are formed in the clockwise and counterclockwise directions when entering the ring, forming a collision zone on the opposite side of the air inlet. The airflow velocity in the lower part of the air ring is higher than that in the upper part.

[0041] Since the gas rising channel and the air rising channel are provided with branch pipes in the premixing zone and form an angle with the circumferential direction, the gas in the combustion chamber rotates and flows in the circumferential direction. Since the momentum of the gas is greater than the momentum of the air, the gas will drive the air to rotate and flow in the circumferential direction. In the combustion chamber, the airflow is compressed in the clockwise direction and moves upward, and the swirl intensity is gradually weakened. Previous researchers have performed numerical simulation calculations on swirl burners. Although the air-gas mass flow rate distribution is uneven, the gas is symmetrically distributed in the circumferential direction, which is conducive to air-gas mixing.

[0042] The CO concentration is relatively high near the gas inlet, and the oxygen concentration is relatively low on the opposite side of the inlet. The distribution trend of oxygen concentration is basically opposite to that of CO concentration. Where the oxygen concentration is high, the carbon monoxide concentration is low, and vice versa. Fig.14 , 15 shown.

[0043] from Fig.17 It can be seen that in the utility model, the CO concentration at the edge of the furnace body on the y1 section is higher, and the concentration in the center area is lower. When it reaches the y2 section, the CO remaining is 0.03. On the horizontal sections y2 and above, most of the CO has been burned. As the gas moves upward along the edge, the coal gas and air continue to mix and burn strongly. The maximum CO concentration at the y3 section is 0.7. In the area above the y4 section, most of the airflow has been burned, and only very little CO exists.

[0044] from Fig.18 It can be seen that in the utility model furnace body, on the y1 section, the O2 concentration at the edge is higher, and the concentration in the center area is lower. When it comes to the y4 section, the maximum O2 is 1.159. At the Y5 and Y6 sections, most of the O2 has been burned, and only a very small amount of O2 exists. Fig.19 It can be seen that the velocity value in the central area of ​​each horizontal section is the smallest, so the distribution of O2 and CO on the center line is statistically analyzed. Fig.19 The left side shows that most of the oxygen moves upward, and there is no situation where the oxygen flow rate flows out of the mixing burner and directly enters the regenerator. Fig.19 The right side shows that CO burns more completely in the furnace.

[0045] The temperature at the center of the Y1-y2 section of the utility model is higher, and the temperature at the edge is lower. The temperature distribution on the Y1-y3 section is uneven until the temperature of the y4 and above sections gradually mixes, indicating that the mixture is continuously burned during the upward movement. Fig. 20 shown.

[0046] The overall temperature distribution of the combustion chamber of the utility model is uniform, the lowest temperature in the flame center is 1048K, the highest temperature in the dome area is 1674K, the highest temperature in the combustion chamber outlet section is 1653K, the lowest temperature is 1641K, and the maximum temperature difference is 12K, indicating that the temperature distribution in the combustion chamber outlet section is relatively uniform; the average temperature in the combustion chamber outlet section is 1646K, which is 182K higher than the average temperature in the combustion chamber outlet section of the 202320194190.X top-fired hot blast furnace of 1464K. Fig.16 , 21 shown.

[0047] The parameter comparison between the catenary arch top-burning hot blast furnace of the utility model and the 202320194190.X top-burning hot blast furnace is shown in Table 1.

[0048] Table 1 Comparison results between the utility model hot blast stove and 202320194190.X top-burning hot blast stove

[0049] 202320194190.X Top-burning hot air furnace Utility model hot air stove Air burner size / mm×mm 43×250 43×250 Gas burner size / mm×mm 75×250 75×250 <![CDATA[Outlet cross-section velocity / m·s -1 > 3.6-5.2 6.4～7.1 CO content in combustion chamber outlet section (ppm) 31800 107 <![CDATA[O2 concentration at the combustion chamber outlet cross-section]]> 0.0120 0.0095 Average temperature of combustion chamber outlet section K 1464 1646

[0050] Compared with the prior art, the utility model has the following advantages:

[0051] 1. After the coal gas and air are mixed in the premixing zone, they move upward along the edge of the combustion chamber. The gas streams cross-mix and burn near the dome, then turn back and move downward into the regenerator. There is a swirl in the horizontal section of the combustion chamber, and the swirl intensity gradually decreases as it moves upward.

[0052] 2. The temperature distribution of the hot blast furnace combustion chamber outlet section is relatively uniform, the average CO concentration in the flue gas is 107ppm, and the average O2 concentration is 0.0095, indicating that the gas and air are well mixed and the combustion is sufficient;

[0053] 3. Compared with the numerical simulation results of the 202320194190.X top-burning hot blast stove, the CO and O2 concentrations on the outlet cross section of the combustion chamber of the utility model top-burning hot blast stove are lower than those of the 202320194190.X top-burning hot blast stove, and the outlet temperature of the combustion chamber is high, which is an innovation in the top-burning hot blast stove and has good economic and social benefits.

[0054] It should be pointed out that the above is only a preferred embodiment of the utility model, and does not impose any form of limitation on the utility model. Any technician familiar with the profession can use the technical content disclosed above to make changes or modify it into an equivalent embodiment with equivalent changes without departing from the technical solution of the utility model, which all fall within the protection scope of the utility model.

Claims

1. An internal premixed multi-burner mixed combustion strong swirl ultra-low emission hot air furnace, comprising a furnace body, characterized in that: The furnace body (1) is composed of a vault (2), a combustion chamber (3), a burner (9), a heat storage chamber (4) and a cold air chamber (13) at the bottom of the furnace body from top to bottom. The combustion chamber (3) is composed of an upper vault inner wall and a lower straight wall inner wall. A hot air outlet (16) connected to the outside is arranged on the side wall of the straight wall. A gas inlet (5) and an air inlet (6) are arranged on the outer wall of the furnace body corresponding to the burner (9). The gas inlet (5) is connected to a gas ring channel (7) built into the furnace wall. The air inlet (6) is connected to an air ring channel (8) built into the furnace wall. The gas ring channel (7 ) is connected to the gas rising channel (10) of the burner (9), the air ring channel (8) is connected to the air rising channel (11) of the burner (9), the gas rising channel (10) and the air rising channel (11) are arranged alternately, an air branch pipe is arranged at the top of the air rising channel (11) for flow diversion, and a gas branch pipe is arranged at the top of the gas rising channel (10) for flow diversion, the air branch pipe and the gas branch pipe are both connected to the mixing swirl nozzle (12) through the premixing zone, and a cold air inlet (14) and a smoke outlet (15) communicating with the outside of the furnace body (1) are arranged on the cold air chamber (13).

2. The internal premixed multi-burner mixed combustion strong swirl ultra-low emission hot air furnace according to claim 1 is characterized in that: The burners (9) are arranged around the inner wall of the furnace body (1) in a plurality of interconnected manners, each burner (9) comprising a gas rising channel (10) and an air rising channel (11), each gas rising channel (10) having two gas branch pipes at the top end, and each air rising channel (11) having two air branch pipes at the top end.

3. The internal premixed multi-burner mixed combustion strong swirl ultra-low emission hot air furnace according to claim 1 is characterized in that: The angle between the gas branch pipe and the vertical direction is 10-25°, and the angle between the air branch pipe and the vertical direction is 10-25°.

4. The internal premixed multi-burner mixed combustion strong swirl ultra-low emission hot air furnace according to claim 1 is characterized in that: The number of the mixing swirl nozzles (12) matches the number of the burners (9).

5. The internal premixed multi-burner mixed combustion strong swirl ultra-low emission hot air furnace according to claim 1 is characterized in that: The angle between the mixing swirl nozzle (12) and the vertical direction is 10°-25°, and all the mixing swirl nozzles (12) are inclined in the same direction along the circumferential surface.

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