Low-nitrogen hot blast stove with furnace shell cooling device

Abstract

The utility model discloses a low-nitrogen hot blast stove with a stove shell cooling device, which relates to the technical field of hot blast stoves and comprises a stove shell outer wall, a cooling jacket and a jacket inner wall which are arranged in the stove shell outer wall, and a rotational flow device and a fire protection cylinder which are arranged in the jacket inner wall. The rotational flow device and the fire protection cylinder divide the space in the inner wall of the jacket into a hearth and a dilution air distribution chamber, a combustor is arranged on the side portion of the dilution air distribution chamber and in the middle of the outer wall of the furnace shell, and a dilution air inlet is formed in the outer wall of the furnace shell. According to the low-nitrogen hot air furnace with the furnace shell cooling device, heated dilution air spirally flows to the hot air outlet from the position of the rotational flow device at a high speed, high-temperature combustion flue gas is isolated from the inner wall of the jacket by high-speed rotating airflow under the action of centrifugal force, the temperature of the inner wall of the jacket is effectively reduced, and the service life of the low-nitrogen hot air furnace is prolonged. The high-speed rotating airflow entrains high-temperature flue gas in the combustion boundary area, a large amount of heat generated by fuel combustion is taken away, and nitrogen in combustion air is prevented from forming nitrogen oxide under the high-temperature condition.

Description

Technical Field

[0001] The utility model relates to the technical field of hot blast furnaces, in particular to a low-nitrogen hot blast furnace with a furnace shell cooling device. Background Art

[0002] The fuels burned in existing gas hot blast furnaces include coal gas, natural gas, etc. The gas is burned to generate high-temperature flue gas, which is mixed with the dilution air with a lower temperature in the hot blast furnace to produce hot air that meets the temperature requirements. The amount of hot air delivered and the temperature of the hot air are controlled by adjusting the gas load, the amount of combustion-supporting air and the amount of dilution air. The mixed dilution air can be low-temperature flue gas or normal temperature air.

[0003] The existing hot blast furnace has the following disadvantages: the existing hot blast furnace structure has a furnace temperature of more than 1200℃. In order to prevent the hot blast furnace shell from overheating, the hot blast furnace lining has high requirements for refractory insulation. In order to prevent the hot blast furnace shell from heat dissipation and scalding, it even requires external insulation. In this way, the furnace shell in the insulation layer cannot effectively dissipate heat, and the furnace shell is prone to overheating and burning. The existing hot blast furnace lining refractory insulation layer requires a lot of on-site masonry work, the furnace body is bulky, and the construction period is long; the high-temperature flue gas burned in the existing hot blast furnace is mixed with the dilution air at the tail of the hot blast furnace, the hot blast furnace has a large high-temperature combustion area, and the temperature-type nitrogen oxide generation environment is throughout most of the hot blast furnace, resulting in a high concentration of nitrogen oxides in the exhaust flue gas. Utility Model Content

[0004] The purpose of the utility model is to solve the above problems and provide a low-nitrogen hot blast furnace with a furnace shell cooling device. The heated dilution air flows in a high-speed spiral from the position of the swirl device to the position of the hot blast outlet. Under the action of centrifugal force, the high-speed rotating airflow isolates the high-temperature combustion flue gas from the inner wall of the jacket, effectively reducing the temperature of the inner wall of the jacket. The high-speed rotating airflow sucks the high-temperature flue gas in the combustion boundary area, takes away a large amount of heat generated by the fuel combustion, reduces the peripheral temperature of the combustion area, destroys the generation environment of temperature-type nitrogen oxides, and inhibits the nitrogen in the combustion-supporting air from forming nitrogen oxides under high temperature conditions, thereby improving the product's performance and extending its service life.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] A low-nitrogen hot blast furnace with a furnace shell cooling device comprises a furnace shell outer wall, a cooling jacket and a jacket inner wall are arranged inside the furnace shell outer wall, a swirl device and a fire protection tube are arranged inside the jacket inner wall, the swirl device and the fire protection tube separate the space inside the jacket inner wall into a furnace and a dilution air distribution chamber, a burner is arranged on the side of the dilution air distribution chamber and in the middle of the furnace shell outer wall, a dilution air inlet is arranged on the furnace shell outer wall, and the swirl device guides the heated dilution air spiral to flow in the direction of the hot air outlet to reduce the temperature of the jacket inner wall.

[0007] As a further improvement of the above solution, the fire protection tube is configured as a cylindrical tube structure, and the diameters of the multiple fire protection tubes gradually decrease along the direction of the burner.

[0008] As a further improvement of the above solution, the swirl device has a sheet-like structure and is evenly arranged between adjacent fire protection tubes, and forms an angle of 30-45° with the axis.

[0009] As a further improvement of the above solution, the burner is a gas burner, and a combustion-supporting air inlet and a gas inlet are provided on the burner.

[0010] As a further improvement of the above solution, the inner wall of the jacket is a cylindrical barrel structure, which is made concentrically with the outer wall of the furnace shell.

[0011] As a further improvement of the above solution, the cooling jacket is arranged between the outer wall of the furnace shell and the inner wall of the jacket, and a guide plate is arranged in the cooling jacket.

[0012] As a further improvement of the above solution, the dilution air inlet is externally connected to a hot air furnace connection port, and normal temperature dilution air enters the cooling jacket from the dilution air inlet position.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] The heated dilution air flows in a high-speed spiral from the swirl device to the hot air outlet. Under the action of centrifugal force, the high-speed rotating airflow isolates the high-temperature combustion flue gas from the inner wall of the jacket, effectively reducing the temperature of the inner wall of the jacket. The high-speed rotating airflow sucks the high-temperature flue gas in the combustion boundary area, takes away a large amount of heat generated by the fuel combustion, reduces the peripheral temperature of the combustion area, destroys the generation environment of temperature-type nitrogen oxides, and inhibits the formation of nitrogen oxides in the combustion-supporting air under high temperature conditions, thereby improving the product's performance and extending its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the main structure of the utility model.

[0016] Figure 2 It is a side structural schematic diagram of the utility model.

[0017] Figure 3 It is a three-dimensional structural schematic diagram of the cyclone device of the utility model.

[0018] The text markings in the figure are as follows: 1. Burner; 2. Outer wall of furnace shell; 3. Cooling jacket; 4. Inner wall of jacket; 5. Furnace; 6. Dilution air inlet; 7. Hot air outlet; 8. Swirl device; 9. Fire protection tube; 10. Dilution air distribution chamber; 11. Combustion-supporting air inlet; 12. Gas inlet. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solution, the utility model is described in detail below in conjunction with embodiments. The description in this section is only exemplary and explanatory and should not have any limiting effect on the protection scope of the utility model.

[0020] like Figure 1-3 As shown, the specific scheme of this embodiment is: a low-nitrogen hot blast furnace with a furnace shell cooling device, including a furnace shell outer wall 2, a cooling jacket 3 and a jacket inner wall 4 are arranged in the furnace shell outer wall 2, a swirl device 8 and a fire protection tube 9 are arranged in the jacket inner wall 4, the swirl device 8 and the fire protection tube 9 separate the space inside the jacket inner wall 4 into a furnace 5 and a dilution air distribution chamber 10, a burner 1 is arranged on the side of the dilution air distribution chamber 10 and in the middle of the furnace shell outer wall 2, a dilution air inlet 6 is arranged on the outer wall of the furnace shell outer wall 2, and the swirl device 8 guides the heated dilution air spiral to flow in the direction of the hot air outlet 7 to reduce the temperature of the jacket inner wall 4.

[0021] Specifically, the heated dilution air flows in a high-speed spiral from the swirl device 8 to the hot air outlet 7. Under the action of centrifugal force, the high-speed rotating airflow isolates the high-temperature combustion flue gas from the inner wall 4 of the jacket, effectively reducing the temperature of the inner wall 4 of the jacket. The high-speed rotating airflow sucks the high-temperature flue gas in the combustion boundary area, takes away a large amount of heat generated by the fuel combustion, reduces the peripheral temperature of the combustion area, destroys the generation environment of temperature-type nitrogen oxides, and inhibits the nitrogen in the combustion air from forming nitrogen oxides under high temperature conditions, thereby improving the performance of the product and extending its service life.

[0022] like Figure 1 As shown, as a preferred embodiment of the above embodiment, the fire protection tube 9 is configured as a cylindrical tube structure, and the diameters of the plurality of fire protection tubes 9 gradually decrease along the direction of the burner 1 .

[0023] Specifically, the fire protection tube 9 can be a stainless steel cylindrical tube (or trumpet tube), with at least 2 levels and no more than 8 levels.

[0024] like Figure 1 As shown, as a preferred embodiment of the above embodiment, the swirl device 8 is a sheet-like structure and is evenly arranged between adjacent fire protection tubes 9, and forms an angle of 30-45° with the axis.

[0025] Specifically, after the diluted air passes through the cyclone device 8, the airflow direction changes and it rotates at high speed and flows toward the hot air outlet 7. The cyclone device 8 has more than two stages. When the hot air furnace outlet temperature is 900°C, there are two stages, and one stage is added for every 100°C decrease in the outlet temperature.

[0026] like Figure 1As shown, as a preferred embodiment of the above embodiment, the burner 1 is a gas burner, and a combustion air inlet 11 and a gas inlet 12 are provided on the burner 1.

[0027] Specifically, the combustion air inlet 11 and the fuel gas inlet 12 respectively provide combustion air and fuel gas. The fuel gas and combustion air are mixed according to the theoretical air-fuel ratio before entering the burner 1, and are premixed and ignited through the burner 1.

[0028] like Figure 1 As shown, as a preferred embodiment of the above embodiment, the inner wall 4 of the jacket is a cylindrical barrel structure, which is made concentrically with the outer wall 2 of the furnace shell.

[0029] like Figure 1 As shown, as a preferred embodiment of the above embodiment, the cooling jacket 3 is arranged between the outer wall 2 of the furnace shell and the inner wall 4 of the jacket, and a guide plate is arranged in the cooling jacket 3.

[0030] like Figure 1 As shown, as a preferred embodiment of the above embodiment, the dilution air inlet 6 is externally connected to the hot air furnace connection port, and the normal temperature dilution air enters the cooling jacket 3 from the position of the dilution air inlet 6 .

[0031] The specific working principle of this utility model:

[0032] The heated dilution air flows from the dilution air distribution chamber 10 through the swirl device 8 in a high-speed spiral flow toward the furnace tail. Under the action of centrifugal force, the high-speed rotating airflow isolates the high-temperature combustion flue gas from the inner wall 4 of the jacket, effectively reducing the temperature of the inner wall 4 of the jacket. At the same time, the high-speed rotating airflow sucks the high-temperature flue gas in the combustion boundary area, takes away a large amount of heat generated by the combustion, reduces the peripheral temperature of the combustion area, destroys the generation environment of temperature-type nitrogen oxides, and inhibits the formation of nitrogen oxides in the air under high temperature conditions.

[0033] Before entering the burner 1, the fuel gas and the combustion-supporting air are matched according to the theoretical air-fuel ratio, and are premixed and ignited by the burner 1. The main combustion reaction starts at the position of the hot blast furnace near the burner 1. At this time, the temperature is low and the flame is unstable. In order to avoid the interference of a large amount of dilution air entering the combustion flame, the amount of dilution air increases step by step. Some of the unburned mixed gas flows to the tail of the furnace with the hot flue gas, the combustion reaction rapidly intensifies, and the combustion heat increases. If the reaction heat cannot be taken away in time, the temperature rises in a large area in the combustion area of ​​the hot blast furnace 5, and thermal nitrogen oxides are easily formed. The dilution air enters at a high speed through the swirl channel, sucks and mixes the high-temperature flue gas, and takes away the heat generated by the combustion in time, thereby reducing the temperature of the combustion area.

[0034] The utility model has the following advantages: the normal temperature dilution wind cools the outer wall 2 of the furnace shell through the cooling jacket 3 of the hot blast furnace, the dilution wind flows toward the furnace tail at a high speed through the swirl device 8, the inner wall 4 of the jacket is not in direct contact with the high temperature flue gas from the combustion in the furnace 5, the temperature of the outer wall 2 of the furnace shell of the hot blast furnace is effectively reduced, and the outer wall 2 of the furnace shell does not need external insulation; in addition, the high-speed rotating airflow sucks the high temperature flue gas in the combustion boundary area, takes away a large amount of heat generated by the combustion, reduces the peripheral temperature of the combustion area in the furnace 5, destroys the generation environment of temperature-type nitrogen oxides, inhibits the nitrogen in the air from forming nitrogen oxides under high temperature conditions, and discharges flue gas NO X The concentration can be controlled at 50mg / Nm 3 .

[0035] It should be noted that, in this article, the terms include, contain or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. Specific examples are used in this article to illustrate the principle and implementation of the technical solution of the utility model. The above examples are only used to help understand the method and core idea of ​​the utility model. The above are only preferred implementations of the utility model. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, for ordinary technicians in this technical field, without departing from the principle of the utility model, several improvements, modifications or changes can be made, and the above technical features can also be combined in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concept and technical solution of the utility model to other occasions without improvement, should be regarded as the protection scope of the utility model.

Claims

1. A low nitrogen hot air furnace with a furnace shell cooling device, characterized in that: The invention comprises a furnace shell outer wall (2), a cooling jacket (3) and a jacket inner wall (4) are arranged in the furnace shell outer wall (2), a swirl device (8) and a fire protection tube (9) are arranged in the jacket inner wall (4), the swirl device (8) and the fire protection tube (9) separate the space inside the jacket inner wall (4) into a furnace chamber (5) and a dilution air distribution chamber (10), a burner (1) is arranged on the side of the dilution air distribution chamber (10) and in the middle of the furnace shell outer wall (2), a dilution air inlet (6) is arranged on the furnace shell outer wall (2), and the swirl device (8) guides the heated dilution air spirally to flow in the direction of the hot air outlet (7) to reduce the temperature of the jacket inner wall (4).

2. A low nitrogen hot blast furnace with a furnace shell cooling device according to claim 1, characterized in that: The fire protection tube (9) is configured as a cylindrical tube structure, and the diameters of the plurality of fire protection tubes (9) gradually decrease along the direction of the burner (1).

3. A low nitrogen hot blast furnace with a furnace shell cooling device according to claim 2, characterized in that: The swirl device (8) is in a sheet-like structure and is evenly arranged between adjacent fire protection tubes (9) at an angle of 30-45° to the axis.

4. The low nitrogen hot blast furnace with a furnace shell cooling device according to claim 1, characterized in that: The burner (1) is a gas burner, and a combustion-supporting air inlet (11) and a gas inlet (12) are provided on the burner (1).

5. The low nitrogen hot blast furnace with a furnace shell cooling device according to claim 1, characterized in that: The inner wall (4) of the jacket is a cylindrical barrel structure and is manufactured concentrically with the outer wall (2) of the furnace shell.

6. The low nitrogen hot blast furnace with a furnace shell cooling device according to claim 1, characterized in that: The cooling jacket (3) is arranged between the outer wall (2) of the furnace shell and the inner wall (4) of the jacket, and a guide plate is arranged inside the cooling jacket (3).

7. The low nitrogen hot blast furnace with a furnace shell cooling device according to claim 3, characterized in that: The dilution air inlet (6) is externally connected to a hot air furnace connection port, and normal temperature dilution air enters the cooling jacket (3) from the position of the dilution air inlet (6).

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