Top combustion type hot blast stove

Abstract

The top combustion type hot air furnace comprises a hot air mixing chamber, a combustion chamber, a heat storage chamber and a cold air chamber which are sequentially communicated, the hot air mixing chamber is arranged at the top of the top combustion type hot air furnace, and a secondary combustion air inlet and a hot air outlet are formed in the hot air mixing chamber; the combustion chamber is communicated with the hot air mixing chamber, the combustion chamber is provided with a flame stabilizing device, the flame stabilizing device is formed by stacking a plurality of flame stabilizing units, each flame stabilizing unit is provided with a plurality of first gas channels and second gas channels, and at least part of the second gas channels are communicated through the first gas channels; the flame stabilizing unit is of a honeycomb structure; the combustor is arranged at the bottom of the vault of the top combustion type hot blast stove and comprises a primary combustion air inlet, a gas inlet, a gas loop, an air loop and a mixing loop, and the mixing loop is communicated with the combustion chamber through a grid furnace wall; the cold air chamber is provided with a cold air inlet and a smoke outlet. According to the top combustion type hot blast stove, generation of nitric oxide can be reduced, and the combustion efficiency is improved.

Description

Technical Field

[0001] This application relates to the technical field of hot blast stoves, and more specifically, to a top combustion hot blast stove. Background Art

[0002] The hot blast stove is the main equipment for the blast furnace ironmaking process and provides the hot blast heating project for blast furnace ironmaking. Usually, three or four hot blast stoves are configured for one blast furnace, and the hot blast stoves work alternately through the cycle of firing and air supply.

[0003] According to the classification of the layout structure form of the hot blast stove burner, the main forms are top combustion hot blast stoves, internal combustion hot blast stoves, and external combustion hot blast stoves. Due to the continuous optimization and improvement of the structure of the top combustion hot blast stove, the top combustion hot blast stove has gradually become the main configuration form of the blast furnace hot blast stove system.

[0004] With the progress of steel industry technology, higher requirements are put forward for blast furnace ironmaking in terms of energy conservation, environmental protection, and low carbon. The energy efficiency and low nitrogen oxide emission of the combustion flue gas of the top combustion hot blast stove system are important issues for hot blast stoves. Therefore, how to reduce the concentration of nitrogen oxides in the flue gas has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a top combustion hot blast stove to reduce the concentration of nitrogen oxides in the flue gas.

[0006] To achieve the above purpose, this application provides the following technical solutions:

[0007] A top combustion hot blast stove, comprising:

[0008] A hot air mixing chamber, which is arranged at the top of the top combustion hot blast stove. A secondary combustion air inlet and a hot air outlet are arranged on the hot air mixing chamber;

[0009] A combustion chamber, which is communicated with the hot air mixing chamber. A stable flame device is arranged in the combustion chamber. The stable flame device is formed by stacking a plurality of stable flame units. Each stable flame unit has a plurality of first gas channels and a plurality of second gas channels. For each stable flame unit, at least part of the second gas channels are communicated through the first gas channels, so that each stable flame unit has a honeycomb structure; the corresponding second gas channels of the stacked stable flame units are sequentially communicated;

[0010] A burner, which is arranged at the bottom of the arch roof of the top combustion hot blast stove. The burner includes a primary combustion air inlet, a gas inlet, a gas ring channel, an air ring channel, and a mixing ring channel. A plurality of gas nozzles are arranged on the gas ring channel, and a plurality of air nozzles are arranged on the air ring channel. Each gas nozzle and each air nozzle are communicated with the mixing ring channel, and the mixing ring channel is communicated with the combustion chamber through a grid furnace wall;

[0011] The regenerator chamber, which is connected to the combustion chamber;

[0012] The cold air chamber, which is connected to the regenerator chamber and is provided with a cold air inlet and a flue gas outlet.

[0013] Optionally, in the above top-fired hot blast stove, for each stable flame unit, each first gas passage is connected to a part of the second gas passages, and each first gas passage is connected to the second gas passage located at the center, so that each second gas passage is connected;

[0014] For each stable flame unit at the same height, the second gas passages located at the center are all connected.

[0015] Optionally, in the above top-fired hot blast stove, the shape of each first gas passage is U-shaped.

[0016] Optionally, in the above top-fired hot blast stove, the height of the air ring channel is higher than that of the gas ring channel, the mixing ring channel is formed by enclosing the inner wall of the air ring channel and the grid furnace wall, and the grid furnace wall is provided with a plurality of grid holes for gas passage.

[0017] Optionally, in the above top-fired hot blast stove, the hot blast mixing chamber is provided with a hot blast mixing air inlet, and the axes of the hot blast mixing air inlet and the hot blast outlet are at the same height.

[0018] Optionally, in the above top-fired hot blast stove, the secondary combustion air inlet is arranged at the top of the hot blast mixing chamber, the secondary combustion air inlet is provided with a secondary combustion air nozzle, and the secondary combustion air nozzle is arranged facing the stable flame device.

[0019] Optionally, in the above top-fired hot blast stove, the amount of primary combustion air entering through the primary combustion air inlet is 0.5 to 0.8 times of the total amount of combustion air, and the amount of secondary combustion air entering through the secondary combustion air inlet is 0.5 to 0.2 times of the total amount of combustion air.

[0020] Optionally, in the above top-fired hot blast stove, the combustion temperature range of the combustion chamber is 1350°C - 1410°C.

[0021] Optionally, in the above top-fired hot blast stove, the walls of the hot blast mixing chamber, the walls of the combustion chamber, the burner and the walls of the regenerator chamber are connected by a labyrinth.

[0022] Optionally, in the above top-fired hot blast stove, the burner is a ceramic burner.

[0023] As can be seen from the above solution, in the top-fired hot blast stove disclosed in this application, under the blocking effect of the grid furnace wall, gas and air are preliminarily mixed in the mixing loop and then enter the combustion chamber for combustion, which can improve the combustion efficiency of the gas and reduce the generation of nitrogen oxides during combustion; the setting of the stable flame device can reduce the temperature of the flue gas, achieve uniform distribution of the flue gas, form short flame combustion, realize uniform distribution of the material flow and energy flow of the combustion flue gas, can reduce the generation of nitrogen oxides, and improve the working efficiency of the top-fired hot blast stove; the primary combustion-supporting air and the secondary combustion-supporting air are respectively introduced, which can achieve staged combustion, can reduce the peak flame temperature, reduce the local maximum temperature of the flue gas, and can also reduce the oxygen concentration in the flue gas and reduce the generation of nitrogen oxides; at the same time, the flow direction of the secondary combustion-supporting air is opposite to that of the primary flue gas, forming countercurrent combustion, and the countercurrent combustion is more sufficient, which can reduce the generation of nitrogen oxides and improve the combustion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 is a schematic structural diagram of the top-fired hot blast stove disclosed in the embodiment of the present application;

[0026] Figure 2 is a top view of the stable flame device disclosed in the embodiment of the present application;

[0027] Figure 3 is Figure 2 the sectional view taken along line A-A in

[0028] Figure 4 is a side view of the stable flame unit disclosed in the embodiment of the present application;

[0029] Figure 5 is a gas flow diagram during the firing period of the top-fired hot blast stove disclosed in the embodiment of the present application;

[0030] Figure 6 is a gas flow diagram during the air supply period of the top-fired hot blast stove disclosed in the embodiment of the present application;

[0031] Figure 7 is a gas flow diagram of the combustion chamber during the firing period of the top-fired hot blast stove disclosed in the embodiment of the present application.

[0032] Among them, 10 is the hot air mixing chamber, 11 is the secondary combustion-supporting air inlet, 12 is the hot air mixing inlet, and 13 is the hot air outlet;

[0033] 20 is the combustion chamber;

[0034] 30 is the burner, 31 is the primary combustion air inlet, 32 is the gas inlet, 33 is the gas loop, 34 is the air loop, and 35 is the grid furnace wall;

[0035] 40 is the regenerator;

[0036] 50 is the cold air chamber, 51 is the cold air inlet, 52 is the flue gas outlet, and 53 is the grate;

[0037] 60 is the stable flame device, 601 is the first gas passage, 602 is the second gas passage, 603 is the positioning hole, and 61 is the stable flame unit. Detailed implementation manners

[0038] In addition to the problems mentioned in the background art, the existing top-firing hot blast stove also has the following problems:

[0039] (1) During the combustion process of the top-firing hot blast stove, due to low combustion efficiency and low energy conversion efficiency, the fuel consumption is high, the energy conversion rate is low, resulting in energy waste and high flue gas emissions;

[0040] (2) Due to complex blast furnace operating conditions such as high temperature, high pressure, and high oxygen enrichment, abnormal damage, safety hazards, and operating failures occur in the furnace shell in the high-temperature area of the top-firing hot blast stove, high-temperature and high-pressure pipelines, and refractory materials at key parts after commissioning, restricting the increase of blast temperature, the service life of the hot blast stove, and safe operation.

[0041] Explanation of related terms:

[0042] (1) Hot blast stove, a main device in the blast furnace ironmaking process configuration, used to heat air, oxygen, or gas blown into the furnace during blast furnace smelting. Generally, a regenerative heating furnace is adopted. Usually, three or four hot blast stoves are configured for one blast furnace, and the hot blast stoves work alternately to heat air, oxygen, or gas.

[0043] (2) Top-firing hot blast stove, a hot blast stove with a combustion device arranged at the top of the hot blast stove.

[0044] (3) Burner, a combustion device that mixes gas and combustion-supporting air according to the combustion mechanism and sprays them into the furnace.

[0045] (4) Firing of the hot blast stove. The heat storage of the hot blast stove is achieved by heating the regenerator lattice bricks in the furnace of the hot blast stove with the high-temperature flue gas generated by the combustion of gas in the burner. The heat storage process of the hot blast stove is called firing of the hot blast stove.

[0046] (5) Heating and air supply of the hot blast stove. The process of using the heat stored in the regenerator lattice bricks during the firing stage of the hot blast stove to heat air is called heating and air supply of the hot blast stove.

[0047] The main factors affecting the formation of nitrogen oxides during combustion are combustion temperature, residence time of flue gas in the high-temperature zone, concentrations of various components in the flue gas, and mixing degree. Therefore, changing the air-fuel ratio, temperature of combustion air, degree of cooling in the combustion zone, and shape design of the burner can all reduce the formation of nitrogen oxides during combustion. This application starts from reducing the local maximum temperature of combustion flue gas and the oxygen concentration in the flue gas, and discloses a top-fired hot blast stove to reduce the concentration of nitrogen oxides in the flue gas.

[0048] Next, the technical solutions in the embodiments of this application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0049] As Figure 1 shown, the embodiments of this application disclose a top-fired hot blast stove, which includes a hot air mixing chamber 10, a combustion chamber 20, a burner 30, a regenerator 40, and a cold air chamber 50. From the top of the top-fired hot blast stove, the hot air mixing chamber 10, the combustion chamber 20, the regenerator 40, and the cold air chamber 50 are arranged in sequence and are connected in sequence. The burner 30 is arranged around the combustion chamber 20 and the regenerator 40.

[0050] Specifically, the hot air mixing chamber 10 is arranged at the top of the top-fired hot blast stove. A secondary combustion air inlet 11 and a hot air outlet 13 are arranged on the hot air mixing chamber 10. The secondary combustion air inlet 11 is used to introduce secondary combustion air. The combustion chamber 20 is connected to the hot air mixing chamber 10. A stable flame device 60 is arranged in the combustion chamber 20. The stable flame device 60 is formed by stacking a plurality of stable flame units 61. Specifically, as Figures 2 - 4 shown, each stable flame unit 61 has a plurality of first gas channels 601 and a plurality of second gas channels 602. For each stable flame unit 61, at least part of the second gas channels 602 are connected through the first gas channels 601, so that each stable flame unit 61 has a honeycomb structure. The corresponding second gas channels 602 of the stacked stable flame units 61 are connected in sequence. The bottom of the stable flame device 60 is connected to the top of the regenerator 40. Specifically, the second gas channels 602 are connected to the lattice holes of the regenerator checker bricks in the regenerator 40. The cold air chamber 50 is provided with a cold air inlet 51 and a flue gas outlet 52. A grate 53 and support columns are arranged in the cold air chamber 50.

[0051] Preferably, the second gas channels 602 are arranged in the vertical direction (i.e., the extending direction from the top to the bottom of the top-fired hot blast stove), and the first gas channels 601 are arranged perpendicular or obliquely to the second gas channels 602.

[0052] The burner 30 is arranged at the bottom of the arch roof of the top combustion hot blast stove, that is, the burner 30 is arranged around part of the wall of the combustion chamber 20 and part of the wall of the regenerator 40. Specifically, the burner 30 includes a primary combustion-supporting air inlet 31, a gas inlet 32, a gas loop 33, an air loop 34 and a mixing loop. A plurality of gas nozzles arranged circumferentially are provided on the gas loop 33, and a plurality of air nozzles arranged circumferentially are provided on the air loop 34. Each gas nozzle and each air nozzle are communicated with the mixing loop, and the mixing loop is communicated with the combustion chamber 20 through the grid furnace wall 35.

[0053] In the top combustion hot blast stove disclosed in the embodiment of the present application, under the blocking action of the grid furnace wall 35, gas and air are preliminarily mixed in the mixing loop and then enter the combustion chamber 20 for combustion, which can improve the combustion efficiency of the gas and reduce the generation of nitrogen oxides during the combustion process; the setting of the stable flame device 60 can reduce the temperature of the flue gas, realize the uniform distribution of the flue gas, form short flame combustion, and realize the uniform distribution of the material flow and energy flow of the combustion flue gas, which can reduce the generation of nitrogen oxides and improve the working efficiency of the top combustion hot blast stove; the primary combustion-supporting air and the secondary combustion-supporting air are respectively introduced, which can realize staged combustion, reduce the peak temperature of the flame, reduce the local highest temperature of the flue gas, and can also reduce the oxygen concentration in the flue gas and reduce the generation of nitrogen oxides; at the same time, the flow direction of the secondary combustion-supporting air is opposite to the flow direction of the primary flue gas, forming countercurrent combustion. The countercurrent combustion is more sufficient, which can reduce the generation of nitrogen oxides and improve the utilization rate of fuel.

[0054] The specific description process is as follows: During the stove burning stage of the top combustion hot blast stove, as Figure 5 and Figure 7 shown, the black arrows shown in the figure represent the flow direction of air, and the red arrows represent the flow direction of gas and flue gas. The gas enters the gas loop through the gas inlet 32 and is ejected through the gas nozzles. The primary combustion-supporting air enters the air loop 34 through the primary combustion-supporting air inlet 31 and is ejected through the air nozzles. Under the blocking action of the grid furnace wall 35, the gas and the primary combustion-supporting air are preliminarily mixed in the mixing loop and then enter the combustion chamber 20 through the grid furnace wall 35, and are sprayed and distributed along the surface of the stable flame device 60, and incomplete combustion occurs at the same time. Part of the flue gas generated by the primary combustion (referred to as primary flue gas) enters the stable flame device 60 through the first gas channel 601 of the stable flame device 60, transfers heat to the stable flame device 60, can reduce the temperature at the front end of the flame, and at the same time makes the flue gas distribution more uniform. Part of the primary flue gas rises along the surface of the stable flame device 60, which can preheat the mixed gas of gas and primary combustion-supporting air and improve the combustion efficiency.

[0055] The secondary combustion air flows downward through the secondary combustion air inlet 11 via the hot air mixing chamber 10 and enters the combustion chamber 20. The flow direction of the secondary combustion air is opposite to that of the primary flue gas. Part of the secondary combustion air further mixes and burns with the primary flue gas (including the remaining gas and the gas incompletely generated from the flue gas) on the surface of the stable flame device 60. Part of the secondary combustion air enters the stable flame device 60 through the second gas passage 602 and mixes and burns with the gas that has not been completely burned in the first combustion inside the stable flame device 60, forming a combustion mode in which the secondary combustion air and the primary combustion air entrain the gas, making the mixing of the gas and air more sufficient. The secondary flue gas generated by combustion enters the regenerator 40 downward through the second gas passage 602, then enters the cold air chamber 50, and is discharged from the flue gas outlet 52. The top-fired hot blast stove disclosed in the embodiment of the present application can promote the mixing of the gas and air, significantly improve the combustion sufficiency, thereby enhancing the combustion efficiency and thermal efficiency, while reducing pollutant emissions; at the same time, it can reduce the temperature of the flue gas, make the flue gas distribution uniform, and reduce the generation of nitrogen oxides.

[0056] During the air supply stage of the top-fired hot blast stove, as Figure 6 shown, the cold air is introduced from the cold air inlet 51, successively passes through the cold air chamber 50, the regenerator 40, and the stable flame device 60. Part of the cold air flows upward through the second gas passage 602 of the stable flame device 60, and part of the cold air enters the combustion chamber 20 through the first gas passage 601, and then continues to flow upward into the hot air mixing chamber 10. After being heated in the regenerator 40 and the stable flame device 60, it becomes hot air and flows out from the hot air outlet 13 of the hot air mixing chamber 10. Compared with the existing top-fired hot blast stove, the hot air directly enters the top of the hot air mixing chamber 10 and then flows out. In the existing top-fired hot blast stove, part of the hot air is discharged through the hot air outlet 13, and part of the hot air continues to flow upward to the arch top and then turns back and flows out from the hot air outlet 13. There is a local high-temperature area at the arch top, which is likely to cause the refractory material to age or be damaged acceleratedly. The solution of the present application can reduce the local high temperature, and the hot air directly flows out from the hot air outlet 13 after flowing upward to the arch top. In addition, the setting of the stable flame device 60 can further utilize the heat of the flue gas to heat the cold air and reduce the height of the regenerator 40.

[0057] Furthermore, the regenerator 40 includes a high-temperature regenerating section and a low-temperature regenerating section, and the materials of the regenerating checker bricks in the high-temperature regenerating section and the low-temperature regenerating section are the same or different.

[0058] Furthermore, as Figure 2 and Figure 3As shown, for each stable flame unit 61, each first gas channel 601 communicates with a part of the second gas channel 602, and each first gas channel 601 communicates with the second gas channel 602 located at the center, so that each second gas channel 602 communicates to form a honeycomb structure. That is, all the first gas channels 601 can converge to the second gas channel 602 at the center point of the stable flame unit 61, and the center of each first gas channel 601 is the second gas channel 602 located at the center. It should be noted that the stable flame unit 61 is preferably a porous checker brick, and the second gas channel 602 here refers to the existing lattice holes of the porous checker brick, which extends in the direction from the top to the bottom (vertical direction) of the top-fired hot blast stove; taking the second gas channel 602 located at the center as the center point, the channels connecting the second gas channels 602 on the same straight line are the first gas channels 601. Preferably, the first gas channel 601 is perpendicular to the second gas channel 602. It should be noted that for each stable flame unit 61, each of the first gas channels 601 can be at the same height or can include multiple ones at different heights.

[0059] As Figures 2 - 4 shown, each layer of the stable flame units 61 shown in the figure includes three, with a total of two layers, and each stable flame unit 61 includes six first gas channels 601, and each first gas channel 601 communicates through the second gas channel 602 at the center. Preferably, for the stacked stable flame units 61, the centers of each second gas channel 602 are collinear. For the convenience of positioning, positioning holes 603 are provided on each stable flame unit 61. It should be noted that the shape of the porous checker brick shown in the figure is hexagonal, which is only an example here, and other shapes such as rectangular can also be used. The cross-sectional shapes of the first gas channel 601 and the second gas channel 602 can be circular, or can be rectangular, elliptical or arc-shaped, and the specific shapes are not specifically limited.

[0060] Furthermore, for the convenience of processing, the shape of each first gas channel 601 is in a U shape.

[0061] Furthermore, in order to optimize the air flow distribution, the stable flame device 60 is preferably in a frustum shape. This structure can guide the primary flue gas to flow from the wider bottom to the narrower top, forming a gradually shrinking flow channel, and mixing and burning with the secondary combustion air from the top of the top-fired hot blast stove, which can accelerate the air flow and improve the combustion efficiency.

[0062] Furthermore, as Figure 1As shown, the height of the air annular passage 34 is higher than that of the gas annular passage 33, that is, the air annular passage 34 is located above the gas annular passage 33, so that air can diffuse downward more evenly, mix fully with the gas, and promote complete combustion. Specifically, the air annular passage 34 is an annular chamber extending along the side wall of the combustion chamber 20, and the gas annular passage 33 is an annular chamber extending along the side wall of the regenerator 40. A plurality of gas nozzles are arranged at intervals along the circumferential direction of the gas annular passage 33, preferably in a uniformly arranged form. A plurality of air nozzles are arranged at intervals along the circumferential direction of the air annular passage 34, preferably in a uniformly arranged form. This way can improve the intake rate of gas and air, and at the same time improve the mixing effect of gas and air. The mixing annular passage is formed by enclosing the inner wall of the air annular passage 34 and the grid furnace wall 35. The grid furnace wall 35 is provided with a plurality of grid holes for gas to pass through. Preferably, the grid holes are evenly distributed. The evenly distributed grid holes contribute to the full mixing of gas and air, forming a uniform premixed gas, so as to be able to shorten the flame length and form short-flame combustion. The gas spirally enters the combustion chamber 20 along the conical surface, which can improve the air flow distribution, avoid the air flow concentrating in a certain area, and thus improve the combustion uniformity.

[0063] It should be noted that there are three forms of nitrogen oxides generated in the combustion flue gas, namely thermal nitrogen oxides, prompt nitrogen oxides and fuel nitrogen oxides. The nitrogen oxides generated during the combustion process are mainly thermal nitrogen oxides, and there is also a part of prompt nitrogen oxides. Among them, thermal nitrogen oxides are generated by the reaction of nitrogen and oxygen at high temperatures, mainly occurring in the high-temperature zone of the flame; prompt nitrogen oxides are generated by the reaction of nitrogen and hydrocarbon free radicals in the fuel-rich zone at the flame front. Short-flame combustion may reduce the residence time of combustion products in the high-temperature zone, thereby inhibiting the generation of thermal nitrogen oxides, and short flames are achieved by mixing gas and air, which may reduce the local high-temperature peak value and reduce the generation of thermal nitrogen oxides.

[0064] In order to increase the mixing degree of gas and primary combustion-supporting air, grid plates can also be arranged on the grid furnace wall 35, and the grid holes of the grid plates are communicated with the grid holes of the grid furnace wall 35. Specifically, the aperture of the grid holes of the grid plate can be smaller than the aperture of the grid holes of the grid furnace wall 35, or the aperture of the grid holes of the grid plate can be larger than the aperture of the grid holes of the grid furnace wall 35.

[0065] Furthermore, in order to enable the mixed gas after the preliminary mixing of gas and primary combustion-supporting air to form a certain injection angle, in some specific embodiments, the grid furnace wall 35 is arranged obliquely at a preset angle with respect to the axis of the combustion chamber 20.

[0066] Furthermore, in order to make the temperature of the hot air discharged from the hot air outlet 13 reach the preset temperature and avoid the hot air temperature from being too high, such as Figure 7As shown, the hot air mixing chamber 10 is provided with a hot air mixing inlet 12 for introducing cold air. The axis of the hot air mixing inlet 12 and the axis of the hot air outlet 13 are at the same height, so that the cold air can be mixed with the hot air, rapidly cooling the hot air, and thus enabling the temperature of the hot air discharged from the hot air outlet 13 to meet the preset temperature.

[0067] Furthermore, as Figure 7 shown, in order to make the flow direction of the secondary combustion-supporting air reverse to that of the gas and promote full combustion, the secondary combustion-supporting air inlet 11 is arranged at the top of the hot air mixing chamber 10. The secondary combustion-supporting air inlet 11 is provided with a secondary combustion-supporting air nozzle, and the secondary combustion-supporting air nozzle is arranged facing the stable flame device 60. When the secondary combustion-supporting air is sprayed onto the top surface of the stable flame device 60, it can be evenly distributed along the top surface plane of the stable flame device 60. Part of the secondary combustion-supporting air burns with the primary flue gas on the surface of the stable flame device 60, and part of the secondary combustion-supporting air enters the stable flame device 60 through the second gas passage 602 and burns with the primary flue gas. At the same time, the secondary combustion-supporting air can cool the top of the top-fired hot blast stove by passing through the hot air mixing chamber 10, overall reducing the working temperature of the refractories of the top-fired hot blast stove and being beneficial to improving the service life of the refractories. It should be noted that the primary combustion-supporting air and the secondary combustion-supporting air can be sprayed into the top-fired hot blast stove simultaneously, or can be sprayed into the top-fired hot blast stove in sequence according to a preset time, or the secondary combustion-supporting air can be introduced when the oxygen concentration measured by the concentration measuring element arranged in the combustion chamber or the concentration of the products generated by combustion reaches a preset value.

[0068] Furthermore, the gas injection speed is preferably 25 m / s to 50 m / s, the primary combustion-supporting air injection speed is preferably 30 m / s to 55 m / s, and the secondary combustion-supporting air injection speed is preferably 40 m / s to 55 m / s.

[0069] Further, in the firing stage of the top-fired hot blast stove, the amount of primary combustion-supporting air entering through the primary combustion-supporting air inlet 31 is 0.5 to 0.8 times the total amount of combustion-supporting air, and the amount of secondary combustion-supporting air entering through the secondary combustion-supporting air inlet 11 is 0.5 to 0.2 times the total amount of combustion-supporting air. Specifically, when the primary combustion-supporting air is 0.5 times the total amount of combustion-supporting air, the secondary combustion-supporting air is 0.5 times the total amount of combustion-supporting air; when the primary combustion-supporting air is 0.8 times the total amount of combustion-supporting air, the secondary combustion-supporting air is 0.2 times the total amount of combustion-supporting air. In the primary combustion zone (combustion chamber 20), the oxygen concentration is relatively low, and the combustion process is controlled by the mixing process of gas and oxygen. Since the activation energy of the combustion reaction between oxygen and gas is lower than that of the reaction between oxygen and nitrogen atoms, oxygen first reacts with gas to burn. Only when there is surplus oxygen will the reaction between oxygen atoms and nitrogen atoms occur to generate nitrogen oxides. Therefore, as long as the distribution of the oxygen concentration in the furnace is reasonably controlled, no local hot spots appear, and the maximum temperature is suppressed, the temperature in the furnace can be made uniform. Through simulation and experiments, the applicant found that when the ratio of the primary combustion-supporting air to the secondary combustion-supporting air meets the above ratio, the generation amount of nitrogen oxides is relatively small. The secondary combustion occurs at the top and inside of the stable flame device 60. Excess air is introduced through the secondary combustion-supporting air inlet 11 to make the total excess air coefficient greater than 1, so that the unburned gas is completely burned to reduce the generation of nitrogen oxides.

[0070] Further, in order to promote the full combustion of gas and air, the average combustion temperature range of the combustion chamber 20 is 1350°C - 1410°C. A temperature measuring element is arranged in the combustion chamber 20 to measure the combustion temperature of the combustion chamber 20. Through simulation and experiments, the applicant found that when the arch top temperature of the top-fired hot blast stove exceeds 1360°C, the generation rate of nitrogen oxides begins to increase; when the temperature exceeds 1420°C, the generation amount of nitrogen oxides will increase sharply; the longer the reaction time between nitrogen and oxygen under high temperature conditions, the sharper the increase in the generation amount of nitrogen oxides. Therefore, by controlling the combustion temperature of the combustion chamber 20 to meet the above temperature conditions, the generation of nitrogen oxides can be reduced.

[0071] Further, in order to ensure that the hot blast mixing chamber 10, the combustion chamber 20, the burner 30, and the regenerator 40 are not affected by expansion and have good sealing performance, the walls of the hot blast mixing chamber 10, the walls of the combustion chamber 20, the burner 30, and the walls of the regenerator 40 are connected by a labyrinth.

[0072] Further, the burner 30 is an annular rectangular ceramic burner. The ceramic burner has good thermal stability at high temperatures, can withstand the thermal shock of rapid heating and cooling, and reduce cracks or damage caused by thermal stress. The combustion capacity of the burner 30 is preferably 20MW - 200MW.

[0073] It should be noted that the embodiments in this specification are all described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other.

[0074] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0075] Specific examples are used herein to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only for helping to understand the core idea of the present application. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present application, several 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 top-burning hot blast stove, characterized in that: include: A hot air mixing chamber (10), the hot air mixing chamber (10) being arranged at the top of the top-fired hot air furnace, the hot air mixing chamber (10) being provided with a secondary combustion air inlet (11) and a hot air outlet (13); A combustion chamber (20), the combustion chamber (20) being in communication with the hot air mixing chamber (10), the combustion chamber (20) being provided with a stable flame device (60), the stable flame device (60) being formed by stacking a plurality of stable flame units (61), each stable flame unit (61) having a plurality of first gas channels (601) and a plurality of second gas channels (602), and for each of the stable flame units (61), at least a portion of the second gas channels (602) being in communication with each other through the first gas channels (601), so that each of the stable flame units (61) presents a honeycomb structure; and the corresponding second gas channels (602) of each of the stacked stable flame units (61) are in communication with each other in sequence; A burner (30), the burner (30) being arranged at the bottom of the dome of the top-fired hot blast furnace, the burner (30) comprising a primary combustion air inlet (31), a coal gas inlet (32), a coal gas annulus (33), an air annulus (34) and a mixing annulus, the coal gas annulus (33) being provided with a plurality of coal gas nozzles, the air annulus (34) being provided with a plurality of air nozzles, each of the coal gas nozzles and each of the air nozzles being in communication with the mixing annulus, and the mixing annulus being in communication with the combustion chamber (20) via a grid furnace wall (35); a heat storage chamber (40), the heat storage chamber (40) being in communication with the combustion chamber (20); A cold air chamber (50), the cold air chamber (50) being in communication with the heat storage chamber (40), the cold air chamber (50) being provided with a cold air inlet (51) and a smoke outlet (52).

2. The top-fired hot blast stove according to claim 1, characterized in that: For each of the stable flame units (61), each of the first gas channels (601) is connected to a portion of the second gas channel (602), and each of the first gas channels (601) is connected to the second gas channel (602) located at the center, so that each of the second gas channels (602) is connected; For each of the stable flame units (61) located at the same height, the second gas channels (602) located at the center are all connected.

3. The top-fired hot blast stove according to claim 2, characterized in that: Each of the first gas channels (601) is U-shaped.

4. The top-fired hot blast stove according to claim 1, characterized in that: The height of the air annular channel (34) is higher than that of the coal gas annular channel (33); the mixing annular channel is formed by enclosing the inner wall of the air annular channel (34) and the grid furnace wall (35); the grid furnace wall (35) is provided with a plurality of grid holes for gas to pass through.

5. The top-fired hot blast stove according to claim 1, characterized in that: The hot air mixing chamber (10) is provided with a hot air mixing inlet (12), and the axis of the hot air mixing inlet (12) and the axis of the hot air outlet (13) are located at the same height.

6. The top-fired hot blast stove according to claim 1, characterized in that: The secondary combustion-supporting air inlet (11) is arranged at the top of the hot air mixing chamber (10), and the secondary combustion-supporting air inlet (11) is provided with a secondary combustion-supporting air nozzle, and the secondary combustion-supporting air nozzle is arranged directly opposite to the flame stabilization device (60).

7. The top-fired hot blast stove according to any one of claims 1 to 6, characterized in that: The amount of primary combustion air entering through the primary combustion air inlet (31) is 0.5 to 0.8 times the total amount of combustion air, and the amount of secondary combustion air entering through the secondary combustion air inlet (11) is 0.5 to 0.2 times the total amount of combustion air.

8. The top-fired hot blast stove according to claim 7, wherein the combustion temperature of the combustion chamber (20) ranges from 1350°C to 1410°C.

9. The top-fired hot blast stove according to claim 1, characterized in that: The wall of the hot air mixing chamber (10), the wall of the combustion chamber (20), the burner (30) and the wall of the heat storage chamber (40) are connected in a labyrinth manner.

10. The top-fired hot blast stove according to claim 1, characterized in that: The burner (30) is a ceramic burner.

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