A method for avoiding chute drop during the treatment of refractory suspension in a blast furnace

Abstract

The present application relates to a kind of methods for avoiding chute drop when dealing with refractory suspension of blast furnace, comprising: judging that blast furnace reaches refractory suspension state;Adjust chute state;Performing the steps such as reducing wind discharge.The method for avoiding chute drop when dealing with refractory suspension of blast furnace provided by the present application is simple in process, strong in implementability, by adjusting the inclination of chute and the pressure of furnace top, reduce the impact force of gas to chute, avoid chute drop accident in the process of dealing with refractory suspension of blast furnace.

Description

Technical Field

[0001] This invention relates to a method for preventing chute detachment when handling stubborn suspended materials in a blast furnace, and belongs to the field of metal smelting technology. Background Technology

[0002] Blast furnace suspended charge refers to a situation where, due to various reasons, raw materials and fuels cannot move smoothly from top to bottom under gravity during the production process, manifested as unchanged data on the blast furnace top probe. The upper part of the blast furnace contains solid raw materials and fuels, the lower part contains a liquid mixture of iron slag and coke, and the middle part is a soft melt zone between solid and liquid, with very poor permeability. When the gas generated in the lower part of the blast furnace cannot flow smoothly from bottom to top through the furnace interior, it creates significant pressure. This pressure lifts the solid raw materials and fuels, preventing them from moving downwards under gravity, a phenomenon known as suspended charge. In existing technology, after suspended charge occurs in a blast furnace, the common practice is to reduce blast load to allow the charge to descend. Suspended charge that still cannot descend smoothly after three or more reductions in blast load are called stubborn suspended charge. Stubborn suspended charge can only be moved downwards by reducing blast load after the coke in the lower part of the blast furnace has burned and sufficient space has been created by continuously discharging slag and iron. However, the sudden downward movement of a large amount of furnace charge can easily lead to collapse. Once collapsed, a large amount of gas rapidly travels from the lower part of the blast furnace through the softening zone to the upper part, creating a tremendous impact force. Moreover, the higher the pressure inside the furnace, the greater the impact force. The blast furnace charging chute is located at the top of the blast furnace and has a split structure, consisting of the chute body and the goose-head body. The chute body is connected to the airtight box via the goose-head body; the chute and goose-head body are assembled using an insert method, relying on the weight of the chute body itself for locking. When the blast furnace is being charged, if the gas impact force exceeds the weight of the chute body, the chute body and goose-head body will separate under pressure, causing the chute body to detach. After the chute detaches, the blast furnace needs to be shut down for maintenance, with a normal handling time of 10 hours, resulting in a certain amount of economic loss. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the above-mentioned technology and provide a method for handling stubborn suspended material that can prevent chute detachment.

[0004] To solve the above-mentioned technical problems, the technical solution proposed by this invention is: a method for preventing chute detachment when handling stubborn suspended materials in a blast furnace, comprising the following steps: Step 1: Determine if the blast furnace has reached a state of persistent suspended charge; if the blast furnace has suspended charge during production and the charge still cannot descend smoothly after three or more reductions in air volume; and if the air pressure exceeds twice the normal air pressure under the same air volume, and the probe data at the top of the blast furnace does not change; and if the processing time exceeds 4 hours and the charge still does not move downward, then it is determined that the blast furnace has reached a state of persistent suspended charge. Step 2: Adjust the chute status; adjust the chute tilt angle from the stop waiting tilt angle to the minimum allowable tilt angle of the chute; the chute tilt angle is the angle between the chute working face and the blast furnace axis; Step 3: Implement reduced air pressure during the charging process; gradually reduce the furnace top pressure to below 30 kPa during the reduced air pressure process until the furnace charge descends.

[0005] The method provided by this invention for preventing chute detachment during the handling of stubborn suspended materials in a blast furnace is simple in process and highly feasible. By adjusting the chute inclination angle and furnace top pressure, the impact force of gas on the chute is reduced, thus preventing chute detachment accidents during the handling of stubborn suspended materials in a blast furnace. Attached Figure Description

[0006] Figure 1 This is a schematic diagram of a blast furnace structure.

[0007] Figure 2 yes Figure 1 A schematic diagram of the chute structure.

[0008] Figure 3 yes Figure 2 A schematic diagram of the exploded structure of the chute. Detailed Implementation

[0009] Example: The method described in this example for preventing chute detachment when handling stubborn suspended charge in a blast furnace is applied to a smelting blast furnace, such as... Figure 1 As shown, chute 3 is located at the entrance of blast furnace 1, with blast furnace axis 2 serving as an angle reference line. Figure 2 and Figure 3 As shown, the chute 3 is composed of the chute body 4 and the goose head body 5. The goose head body 5 is connected to the transmission shaft of the airtight box at the top of the blast furnace. The chute body 4 is inserted into the goose head body 5. When the chute 3 is subjected to excessive impact, the chute body 4 will detach from the goose head body 5.

[0010] The method for preventing chute detachment during the handling of stubborn suspended charge in blast furnaces, as described in this embodiment, specifically includes the following steps: Step 1: Determine if the blast furnace has reached a state of persistent suspended charge; if, after three or more reductions in air pressure are applied during the blast furnace production process, the charge still cannot descend smoothly; and under the same air volume, the air pressure exceeds twice the normal air pressure, but the probe data at the top of the blast furnace does not change; and if the processing time exceeds 4 hours and the charge still does not move downward, then it is determined that the blast furnace has reached a state of persistent suspended charge; because the charge does not descend, the pressure inside the furnace is very high, with the pressure at the top of the furnace being at least 60 kPa.

[0011] Step 2: Adjust the chute status; adjust the chute tilt angle from the stop waiting tilt angle to the minimum allowable tilt angle of the chute; the tilt angle of the chute is the angle between the working face of the chute and the axis of the blast furnace.

[0012] When the chute is in a stopped and waiting state, its angle is generally greater than 46°. The minimum allowable tilting angle of the chute is generally between 9° and 6°. In this embodiment, taking the maximum of 9° as an example, the impact force on the chute is calculated as follows: F 冲击力 =ρ 煤气 ×s 溜槽 ×v 煤气 2 ;s 溜槽 =L 溜槽 ×W 溜槽 ×sinα 倾角 ;F 冲击力 =ρ 煤气 ×L 溜槽 ×W 溜槽 ×sinα 倾角 ×v 2 煤气 In the formula, F 冲击力 ρ represents the impact force of gas on the chute, expressed in N (Newtons). 煤气 Density of coal gas, unit: kg / m³; s 溜槽 The cross-sectional area of ​​the chute relative to the blast furnace is expressed in meters (m²). 2 L 溜槽 W represents the length of the chute in meters (m). 溜槽 α is the width of the chute, in meters. 倾角 v is the angle between the working face of the chute and the axis of the blast furnace, in degrees. 煤气 The relative velocity between the gas and the chute, in m / s; ρ 煤气 The parameters are the inherent characteristics of the gas itself, L 溜槽 and W 溜槽 For chute equipment parameters, ρ 煤气 L 溜槽 W 溜槽 v 煤气 In this embodiment, the four parameters are fixed constants; therefore, only α needs to be considered. 倾角 One variable. Analyze α using the aforementioned formula. 倾角 The smaller the value, the better F 冲击力 The smaller the value, the better the effect. Adjust the chute tilt angle from 46° to 9°. 溜槽 Then it shrinks by a factor of 4.6, F 冲击力 Reduced to 1 / 4.6.

[0013] Step 3: Implement reduced air pressure during the charging process; during the reduced air pressure process, gradually reduce the furnace top pressure to atmospheric pressure below 30 kPa to reduce the impact force generated when the furnace charge collapses. The reduced air pressure process will continue until the furnace charge descends.

[0014] This invention is not limited to the embodiments described above. All technical solutions formed by equivalent substitutions fall within the scope of protection claimed by this invention.

Claims

1. A method for preventing chute detachment during the handling of stubborn suspended materials in a blast furnace, characterized in that, Includes the following steps: Step 1: Determine if the blast furnace has reached a state of persistent suspended charge; if the blast furnace has suspended charge during production and the charge still cannot descend smoothly after three or more reductions in air volume; and if the air pressure exceeds twice the normal air pressure under the same air volume, and the probe data at the top of the blast furnace does not change; and if the processing time exceeds 4 hours and the charge still does not move downward, then it is determined that the blast furnace has reached a state of persistent suspended charge. Step 2: Adjust the chute state; adjust the chute tilt angle from the stop-and-wait tilt angle to the minimum allowable tilt angle; the tilt angle of the chute is the angle between the chute working face and the blast furnace axis; the stop-and-wait tilt angle is greater than 46°, and the minimum tilt angle is 9° to 6°; Step 3: Implement reduced air pressure during the charging process; during the air pressure reduction process, gradually reduce the furnace top pressure to below 30 kPa, and continue the air pressure reduction process until the furnace charge descends.

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