Iron-making blast furnace coal injection preheating system

Abstract

The utility model provides an ironmaking blast furnace coal injection preheating system which comprises a coal injection mill, an injection tank, a coal injection pipeline and a preheating pipeline, the coal injection mill is connected with the injection tank and used for feeding coal powder into the injection tank, the injection tank is connected with the coal injection pipeline and used for injecting the coal powder into the coal injection pipeline, the preheating pipeline is sleeved on the periphery of the coal injection pipeline, and the preheating pipeline is connected with the injection tank. The preheating pipeline is connected with the hot air waste gas pipeline and used for preheating pulverized coal in the coal injection pipeline. According to the iron-making blast furnace coal injection preheating system provided by the utility model, the coal injection mill is used for grinding and crushing coal into coal powder, the coal powder is fed into the coal injection pipeline through the injection tank, the coal powder in the coal injection pipeline can exchange heat with hot air waste gas in the preheating pipeline, and the coal powder is preheated to be heated by 20-30 DEG C, so that the heat compensation of the blast furnace is favorably reduced, and the energy consumption of the blast furnace is reduced. The replacement ratio of the pulverized coal is increased, the coal injection amount per hour can be increased, the coal injection amount per hour is increased to 26-27 t / h from 23-24 t / h, the coal ratio is increased, the coke ratio is reduced, and the combustion cost of a blast furnace is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of blast furnace ironmaking, and more specifically relates to a coal injection preheating system for an ironmaking blast furnace. Background Art

[0002] In the process of blast furnace ironmaking, coal powder is often injected to improve the smelting process, thereby achieving the purpose of saving coke and increasing production. At present, various enterprises are developing and applying blast furnace coal injection technology. In actual production, with the increase of injection volume, after the coal injection ratio increases to a certain limit, the reduction of coke ratio will be greatly reduced. The main reason is that the injected coal powder cannot be completely burned before the tuyere, and the unburned coal powder will be carried out of the cyclone zone by the rising coal gas. When it is sent to the slag zone, it will be attached to the slag, increasing the viscosity of the initial slag, deteriorating the permeability of the material column, affecting the smooth operation of the blast furnace, and even causing some carbon particles to be taken out of the furnace, causing great waste. Utility Model Content

[0003] The utility model aims to provide a coal injection preheating system for an ironmaking blast furnace, which can improve the coal ratio, reduce the coke ratio and reduce the fuel cost of the blast furnace.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: to provide a coal injection preheating system for an iron-making blast furnace, including a coal injection mill, an injection tank, a coal injection pipeline and a preheating pipeline, the coal injection mill is connected to the injection tank for supplying coal powder into the injection tank, the injection tank is connected to the coal injection pipeline for injecting coal powder into the coal injection pipeline, the preheating pipeline is sleeved on the outer periphery of the coal injection pipeline, and the preheating pipeline is connected to the hot air exhaust gas pipeline for preheating the coal powder in the coal injection pipeline.

[0005] In a possible implementation, the preheating pipe is connected to an induced draft pipe, an outer end of the induced draft pipe is connected to an induced draft fan, and the induced draft pipe is connected to one end of the preheating pipe close to the spray tank.

[0006] In some embodiments, the outer end of the air duct gradually extends in an inclined manner toward a side close to the spray tank.

[0007] In a possible implementation, the coal injection pipeline includes a first pipe arranged near the coal injection mill, a second pipe arranged near the blast furnace body, and a reducer connected between the first pipe and the second pipe, and the diameter of the second pipe is larger than the diameter of the first pipe.

[0008] In some embodiments, the diameter of the first tube is 100 mm-110 mm, and the diameter of the second tube is 130 mm-140 mm.

[0009] In a possible implementation, the coal injection pipeline is further connected to a purge assembly, which is used to blow air into the coal injection pipeline to clear the coal injection pipeline, and a control valve is provided on the purge assembly.

[0010] In some embodiments, the purge assembly includes a blower, an air main connected to the blower, and a plurality of purge branches connected to the air main. The purge branches are arranged at intervals along the direction of the coal injection pipeline. The purge branches penetrate the peripheral wall of the preheating pipeline and extend to be connected to the coal injection pipeline. A plurality of control valves are provided, and are arranged one-to-one with the plurality of purge branches.

[0011] In a possible implementation, the outlet end of the purge branch pipe gradually extends in an inclined manner toward a side close to the blast furnace body.

[0012] In some embodiments, the diameter of the preheating pipe is larger than the diameter of the coal injection pipe, and the diameter of the coal injection pipe is larger than the diameter of the purge branch pipe.

[0013] In a possible implementation, an alloy wear-resistant layer is provided on the inner peripheral wall of the coal injection pipeline.

[0014] The scheme shown in the embodiment of the present application, compared with the prior art, the coal injection preheating system for the iron-making blast furnace provided in the embodiment of the present application utilizes a coal injection mill to grind coal into coal powder, and the coal powder is sent into the coal injection pipeline through a blowing tank. The coal powder in the coal injection pipeline can exchange heat with the hot air exhaust gas in the preheating pipeline, and preheat the coal powder to raise its temperature by 20°C-30°C, which helps to reduce the thermal compensation of the blast furnace, improve the replacement ratio of the coal powder, and help to increase the hourly coal injection amount, so that the hourly coal injection amount is increased from 23-24t / h to 26-27t / h, thereby increasing the coal ratio, reducing the coke ratio, and reducing the combustion cost of the blast furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 A partial cross-sectional structural schematic diagram of a coal injection preheating system for an ironmaking blast furnace provided in an embodiment of the utility model;

[0017] Figure 2 For the utility model embodiment Figure 1 Schematic diagram of the partially enlarged structure of Figure Ⅰ.

[0018] Among them, the reference numerals in the figure are:

[0019] 1. Coal injection mill; 2. Injection tank; 3. Coal injection pipeline; 31. First pipe; 32. Second pipe; 33. Reducer; 4. Preheating pipeline; 5. Induced draft pipe; 51. Induced draft fan; 6. Purge assembly; 61. Air supply fan; 62. Air supply main pipe; 63. Purge branch pipe; 64. Control valve; 7. Hot air exhaust gas pipeline; 8. Blast furnace body. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or indirectly on the other element. It should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "back", "top", "bottom", "inside", "outside", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model. The terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the utility model, the meaning of "several" is two or more, unless otherwise clearly and specifically defined.

[0022] Please also read Figure 1 to Figure 2 The coal injection preheating system for an ironmaking blast furnace provided by the utility model is now described. The coal injection preheating system for an ironmaking blast furnace comprises a coal injection mill 1, an injection tank 2, a coal injection pipeline 3 and a preheating pipeline 4. The coal injection mill 1 is connected to the injection tank 2 for supplying coal powder into the injection tank 2. The injection tank 2 is connected to the coal injection pipeline 3 for injecting coal powder into the coal injection pipeline 3. The preheating pipeline 4 is sleeved on the outer periphery of the coal injection pipeline 3. The preheating pipeline 4 is connected to the hot air exhaust gas pipeline 7 for preheating the coal powder in the coal injection pipeline 3.

[0023] The coal injection preheating system for an iron-making blast furnace provided in the present embodiment, compared with the prior art, utilizes a coal injection mill 1 to grind coal into coal powder, and feeds the coal powder into a coal injection pipe 3 through a blowing tank 2. The coal powder in the coal injection pipe 3 can exchange heat with the hot air exhaust gas in the preheating pipe 4, and preheat the coal powder to raise its temperature by 20°C-30°C, which helps to reduce the thermal compensation of the blast furnace, improve the replacement ratio of the coal powder, and help to increase the hourly coal injection amount, so that the hourly coal injection amount is increased from 23-24t / h to 26-27t / h, thereby increasing the coal ratio, reducing the coke ratio, and reducing the combustion cost of the blast furnace.

[0024] In one possible implementation, please also refer to Figure 1 to Figure 2 The preheating pipe 4 is connected to an induced draft pipe 5 , an outer end of the induced draft pipe 5 is connected to an induced draft fan 51 , and the induced draft pipe 5 is connected to one end of the preheating pipe 4 close to the spray tank 2 .

[0025] In this embodiment, an induced draft duct 5 is provided on the preheating pipe 4, and the air is guided to the outlet end of the preheating pipe 4 through the induced draft fan 51, so that the airflow in the hot air exhaust gas pipe 7 can smoothly flow to the side close to the injection tank 2, thereby realizing heat exchange with the coal powder in the coal injection pipe 3, thereby achieving effective preheating of the coal powder.

[0026] Among them, the temperature of hot air exhaust gas is 200-300℃. Through preheating, the heat of coal powder can be increased by about 20℃ to 30℃ before entering the main body, which helps to increase the coal ratio, reduce the coke ratio and reduce the blast furnace fuel cost.

[0027] In some embodiments, please refer to Figure 1 to Figure 2 , the outer end of the induced draft pipe 5 gradually extends obliquely toward the side close to the spray tank 2. In order to improve the smoothness of hot air exhaust gas transportation, the induced draft pipe 5 and the preheating pipe 4 are arranged at a certain angle, and the induced draft pipe 5 extends obliquely toward the side close to the spray tank 2, so that the air flow of the hot air exhaust gas is smoother, avoiding the transportation obstruction caused by the vertical inflection point, making the air flow channel smoother, and having a good diversion effect.

[0028] In one possible implementation, please also refer to Figure 1 to Figure 2 The coal injection pipeline 3 includes a first pipe 31 arranged near the coal injection mill 1, a second pipe 32 arranged near the blast furnace body 8, and a reducer 33 connected between the first pipe 31 and the second pipe 32, and the diameter of the second pipe 32 is larger than the diameter of the first pipe 31.

[0029] In this embodiment, the coal injection pipeline 3 is in the form of a combination of a first tube 31, a second tube 32 and a reducer 33. When the coal powder is transported from the first tube 31 to the second tube 32, the contact area between the coal powder in the coal injection pipeline 3 and the internal area of ​​the blast furnace body 8 is increased by increasing the diameter of the tube, thereby improving the supply efficiency of the coal powder, so that the coal powder at the tuyere position of the coal injection pipeline 3 close to the blast furnace body 8 can be more fully burned, and the heat compensation required by the blast furnace body 8 to be provided by the preheated coal powder is effectively reduced, which can achieve an increase in the coal injection amount, effectively increase the hourly coal injection amount of the coal injection tank, improve the coal ratio, reduce the coke ratio, and reduce the cost of blast furnace fuel.

[0030] In some embodiments, please refer to Figure 1 to Figure 2 The diameter of the first tube 31 is 100mm-110mm, and the diameter of the second tube 32 is 130mm-140mm. The reducer 33 is used to effectively connect the second tube 32 with a larger diameter at the rear with the first tube 31 with a smaller diameter at the front, so that the ability of conveying pulverized coal from front to back is effectively improved, which facilitates the smooth supply of pulverized coal to the blast furnace body 8, realizes the full combustion of pulverized coal, reduces the heat compensation of the blast furnace body 8, and then improves the coal ratio, reduces the coke ratio, and effectively saves the smelting cost.

[0031] In one possible implementation, please also refer to Figure 1 to Figure 2 The coal injection pipeline 3 is also connected to a purge assembly 6 , which is used to blow air into the coal injection pipeline 3 to clear the coal injection pipeline 3 . The purge assembly 6 is provided with a control valve 64 .

[0032] In this embodiment, when the coal injection pipeline 3 is blocked during the process of conveying coal powder, the injection tank 2 needs to be shut down, and the blocked area needs to be unblocked through the purge assembly 6. The control valve 64 provided on the purge assembly 6 can control the opening and closing of the purge assembly 6 to ensure the smoothness of the coal powder during normal conveying. When purge conveying is required, the purge control valve 64 is opened and the purge assembly 6 is used to purge the blocked position of the coal injection pipeline 3, thereby achieving the function of dredging the coal powder in the coal injection pipeline 3.

[0033] In some embodiments, please refer to Figure 1 to Figure 2 The purge assembly 6 includes a blower 61, an air supply main pipe 62 connected to the blower 61, and a plurality of purge branch pipes 63 connected to the air supply main pipe 62. The purge branch pipes 63 are arranged at intervals along the direction of the coal injection pipeline 3. The purge branch pipes 63 penetrate the peripheral wall of the preheating pipeline 4 and extend to be connected to the coal injection pipeline 3. A plurality of control valves 64 are provided, and are arranged one-to-one with the plurality of purge branch pipes 63.

[0034] In this embodiment, the air blower 61 is mainly used to send air into the air supply main pipe 62, and the air flow in the air supply main pipe 62 is dispersed into multiple purge branches 63. Multiple purge branches 63 are arranged at intervals along the length direction of the coal injection pipeline 3, and the above-mentioned purge branches 63 can purge the corresponding positions of the coal injection pipeline 3. According to the blocked position of the coal injection pipeline 3, the corresponding control valve 64 is selected to open, so as to clear the coal powder blocked in the corresponding area with the help of a certain purge branch 63 or some purge branches 63, so as to ensure the smooth supply of coal powder to the blast furnace body 8.

[0035] In one possible implementation, please also refer to Figure 1 to Figure 2 The outlet end of the purge branch pipe 63 gradually extends toward the side close to the blast furnace body 8. The outlet end of the purge branch pipe 63 gradually extends toward the side close to the blast furnace body 8, which avoids excessive resistance during airflow transportation and helps to improve the smoothness of airflow transportation.

[0036] In some embodiments, please refer to Figure 1 to Figure 2 The diameter of the preheating pipe 4 is larger than that of the coal injection pipe 3, and the diameter of the coal injection pipe 3 is larger than that of the purge branch pipe 63. The purge branch pipe 63 has a smaller diameter, which can provide a relatively high pressure airflow to the coal injection pipe 3, thereby increasing the flow rate of the purge airflow, enhancing the purge and conveying effect, and helping to improve the dredging efficiency of the coal powder.

[0037] In one possible implementation, please also refer to Figure 1 to Figure 2 The inner wall of the coal injection pipeline 3 is provided with an alloy wear-resistant layer. Specifically, a high-chromium alloy wear-resistant layer can be used. The high-chromium alloy wear-resistant layer can not only form a solid protective film on the surface of the equipment, but also effectively resist friction, wear and corrosion. The provision of the alloy wear-resistant layer can effectively improve the wear resistance of the inner wall of the coal injection pipeline 3 and help to extend the service life of the component.

[0038] The above-mentioned coal injection preheating system for the iron-making blast furnace utilizes a coal injection mill 1 to grind coal into coal powder, and feeds the coal powder into a coal injection pipe 3 through an injection tank 2. The coal powder in the coal injection pipe 3 can exchange heat with the hot air exhaust gas in the preheating pipe 4, and preheat the coal powder to raise its temperature by 20°C-30°C, which helps to reduce the thermal compensation of the blast furnace, improve the replacement ratio of coal powder, and help to increase the hourly coal injection amount from 23-24t / h to 26-27t / h, thereby increasing the coal ratio, reducing the coke ratio, and reducing the combustion cost of the blast furnace.

[0039] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. The coal injection preheating system for iron-making blast furnace is characterized by: The invention comprises a coal injection mill (1), a blowing tank (2), a coal injection pipeline (3) and a preheating pipeline (4), wherein the coal injection mill (1) is connected to the blowing tank (2) and is used to supply pulverized coal into the blowing tank (2), the blowing tank (2) is connected to the coal injection pipeline (3) and is used to inject pulverized coal into the coal injection pipeline (3), the preheating pipeline (4) is sleeved on the outer periphery of the coal injection pipeline (3), and the preheating pipeline (4) is connected to a hot air exhaust gas pipeline (7) and is used to preheat the pulverized coal in the coal injection pipeline (3).

2. The coal injection preheating system for an ironmaking blast furnace according to claim 1, characterized in that: The preheating pipe (4) is connected to an induced draft pipe (5), the outer end of the induced draft pipe (5) is connected to an induced draft fan (51), and the induced draft pipe (5) is connected to one end of the preheating pipe (4) close to the spray tank (2).

3. The coal injection preheating system for an ironmaking blast furnace according to claim 2, characterized in that: The outer end of the air duct (5) gradually extends in an inclined manner toward a side close to the spray tank (2).

4. The coal injection preheating system for an ironmaking blast furnace according to claim 1, characterized in that: The coal injection pipeline (3) comprises a first pipe (31) arranged close to the coal injection mill (1), a second pipe (32) arranged close to the blast furnace body (8), and a reducer (33) connected between the first pipe (31) and the second pipe (32), wherein the diameter of the second pipe (32) is larger than the diameter of the first pipe (31).

5. The coal injection preheating system for an ironmaking blast furnace according to claim 4, characterized in that: The diameter of the first tube (31) is 100 mm-110 mm, and the diameter of the second tube (32) is 130 mm-140 mm.

6. The coal injection preheating system for an ironmaking blast furnace according to any one of claims 1 to 5, characterized in that: The coal injection pipeline (3) is also connected to a purge assembly (6), which is used to blow air into the coal injection pipeline (3) to clear the coal injection pipeline (3), and a control valve (64) is provided on the purge assembly (6).

7. The coal injection preheating system for an ironmaking blast furnace according to claim 6, characterized in that: The purge assembly (6) comprises a blower (61), an air supply main pipe (62) connected to the blower (61), and a plurality of purge branch pipes (63) connected to the air supply main pipe (62); the purge branch pipes (63) are arranged at intervals along the direction of the coal injection pipeline (3); the purge branch pipes (63) penetrate the peripheral wall of the preheating pipeline (4) and extend to be connected to the coal injection pipeline (3); a plurality of control valves (64) are provided and are arranged one-to-one corresponding to the plurality of purge branch pipes (63).

8. The coal injection preheating system for an ironmaking blast furnace according to claim 7, characterized in that: The outlet end of the purge branch pipe (63) gradually extends in an inclined manner toward a side close to the blast furnace body (8).

9. The coal injection preheating system for an ironmaking blast furnace according to claim 8, characterized in that: The diameter of the preheating pipe (4) is greater than the diameter of the coal injection pipe (3), and the diameter of the coal injection pipe (3) is greater than the diameter of the purge branch pipe (63).

10. The coal injection preheating system for an ironmaking blast furnace according to any one of claims 1 to 5, characterized in that: An alloy wear-resistant layer is provided on the inner peripheral wall of the coal injection pipeline (3).

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