A burden distribution method for stabilizing the burden surface of a blast furnace

Abstract

A burden distribution method for stabilizing the burden surface of a blast furnace proposed by the present invention pre-sets the burden distribution angles of ore and coke and the burden distribution ratio at each angle to form a burden distribution matrix of the blast furnace. Then, when burden is distributed into the blast furnace according to the burden distribution matrix, the corner positions close to the center are distributed first to form a "retaining wall" of coke and ore, avoiding the burden charged later from sliding into the center of the blast furnace and affecting the central gas flow. At the same time, it can avoid the burden distribution deviation in the central part caused by the inaccuracy of burden distribution.

Description

Technical Field

[0001] The present invention relates to the technical field of blast furnace smelting, and particularly to a burden distribution method for stabilizing the burden surface of a blast furnace. Background Art

[0002] The burden distribution of the bell-less top can be divided into forms such as multi-ring burden distribution, single-ring burden distribution, sector burden distribution, fixed-point burden distribution, etc. With the increase of furnace volume and the requirement of low consumption, the vast majority of blast furnaces adopt multi-ring burden distribution. Multi-ring burden distribution is to distribute ore and coke into the furnace respectively, which is counted as one burden distribution cycle. The ore and coke are distributed into the furnace according to the set angles and specific gravities, generally starting from the largest angle and ending with the smallest angle. There are two modes for the proportion distribution at each angle, one is the weight burden distribution method, and the other is the time burden distribution method. No matter which burden distribution method is used, the burden distribution accuracy will inevitably drop severely in the last gear, and then directly affect the stability of the central gas flow in the blast furnace. Summary of the Invention

[0003] The purpose of the present invention is to provide a burden distribution method for stabilizing the burden surface of a blast furnace, which can effectively stabilize the burden surface of the blast furnace, so as to achieve the purpose of stabilizing the gas flow, smooth operation and low consumption of the blast furnace.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A burden distribution method for stabilizing the burden surface of a blast furnace proposed by the present invention includes the following steps:

[0006] Step 1: Determine a suitable burden distribution matrix according to the smelting requirements of the blast furnace, including the starting angle, angular difference, burden distribution ratio at each angular position, whether there is central coke addition and the specific coke addition amount, and the ratio of ore and coke charged into the furnace for each batch.

[0007] Step 2: Before burden distribution, charge the bunker once with semi-clean gas and then charge it twice with nitrogen. When the pressure in the bunker is greater than the top pressure of the furnace, start the burden distribution chute to enter the rotating state.

[0008] Step 3: Adjust the burden distribution chute to the predetermined first burden distribution angle, then open the lower sealing valve and the charging gate in sequence. The burden materials slide down along the chute into the blast furnace. After the burden distribution at the first angle is completed, adjust to the second angle for burden distribution, and so on until the entire burden distribution is completed; among them, the coke starts to be distributed from the penultimate burden distribution angular position in one burden distribution cycle, and then is distributed from the outside to the inside according to the remaining angular positions in the cycle; the ore starts to be distributed from the smallest burden distribution angular position in one burden distribution cycle, and then is distributed from the outside to the inside according to the remaining angular positions in the cycle.

[0009] The present invention has the following beneficial effects compared with the prior art:

[0010] After the starting angle of the cloth is changed in the present invention, the burden surface in the blast furnace is more stable, and the distribution of the coal gas flow will not be affected by the collapse of the burden surface. The blast furnace can operate smoothly and stably, and the fuel consumption can be reduced. Description of the Drawings

[0011] Figure 1 is a schematic diagram of the cloth trajectory of the present invention;

[0012] Figure 2 is a schematic diagram of the existing cloth cross-section;

[0013] Figure 3 is a schematic diagram of the cloth cross-section of the present invention.

[0014] Among them, the reference numerals in the drawings: 1 - furnace wall; 2 - new burden surface; 3 - original burden surface; 4 - blast furnace center. Detailed Embodiment

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0016] A cloth feeding method for stabilizing the burden surface of a blast furnace proposed by the present invention is as follows Figures 1-3 shown, and the specific implementation process is as follows:

[0017] Step 1: Determine a suitable cloth feeding matrix according to the smelting requirements of the blast furnace, including the starting angles of ore and coke cloth feeding, the angular difference, the cloth feeding ratio of each angular position, the presence or absence of central coke addition, the specific coke addition amount, and the ratio of ore and coke charged into the furnace for each batch.

[0018] Step 2: Before cloth feeding, pressurize the material tank once with semi-clean gas and then pressurize it twice with nitrogen. When the pressure in the material tank is greater than the furnace top pressure, start the cloth feeding chute to enter the rotating state.

[0019] Step 3: Adjust the cloth feeding chute to the predetermined first cloth feeding angle, then open the lower sealing valve and the blanking gate in sequence. The furnace charge slides down along the chute into the blast furnace. After the cloth feeding at the first angle is completed, adjust it to the second angle for cloth feeding, and so on until the entire cloth feeding is completed; among them, the coke starts to be fed from the penultimate cloth feeding angular position in one cloth feeding cycle, and then is fed from the outside to the inside according to the remaining angular positions in the cycle; the ore starts to be fed from the smallest cloth feeding angular position in one cloth feeding cycle, and then is fed from the outside to the inside according to the remaining angular positions in the cycle.

[0020] Since the first angle of the starting burden material is adjusted to a position close to the center of the blast furnace, it is equivalent to artificially forming a coke (ore) dam in the radial direction of the blast furnace throat. The burden materials charged at a large angle later will not roll towards the center of the blast furnace, protecting the stability of the central gas flow. At the same time, due to the influence of weighing errors on the burden materials charged last, which are not precise enough, after adopting this method, this part of the materials can be distributed in the central annulus of the blast furnace, without causing fluctuations in the gas flow and further affecting the stability of the furnace condition.

[0021] Among them, a set of formulas for calculating the landing position of the burden materials, where: the length of the chute l0, the angle of the chute β, the rotational speed of the chute ω, the velocity of the burden materials at the end of the chute C1, the constant g = 9.8, the constant π = 3.14, the torque of the chute e, the distance from the vertical lower edge of the chute to the burden surface h, the constant m / (Q - P), the mass of a piece of material m, the resistance of the ascending gas P, and the gravity of a piece of material Q.

[0022] The formula for calculating the velocity C1 of the burden materials at the end of the chute:

[0023]

[0024] The formula for calculating the landing point Lx:

[0025]

[0026] The formula for calculating the distance n from the center of the blast furnace:

[0027]

[0028] The coke and ore are charged into the blast furnace at a certain angle. The burden materials slide into the furnace along the distribution chute in a parabolic shape, and then the second charging is carried out at the designated position, and so on until the entire charging is completed. The charging trajectory is as Figure 1 shown.

[0029] Currently, when charging coke and ore into the blast furnace, a charging matrix needs to be formed according to the pre-set angles and ratios. The gearbox drives the distribution chute to rotate and tilt according to the set angles. Taking the charging of coke as an example, the weight of each batch of coke is 18 tons, and a total of 16.5 circles are charged. As shown in Table 1, first, 2 circles of coke at 42.5° are charged, then 2 circles of coke at 40.5° are charged, and so on until 4.5 circles of coke at 13° are charged, and the charging of coke in one cycle is completed; then ore is charged. The weight of each batch of ore is 95 tons, and a total of 15 circles are charged. First, 4 circles of ore at 42.5° are charged, then 4 circles of ore at 40.5° are charged, and so on until 2 circles of coke at 33° are charged, indicating that the charging of ore in this cycle is completed. The coke and ore together are counted as one ore batch, that is, one charging cycle.

[0030] Table 1 Charging matrix before adjustment

[0031] angle 42.5 40.5 38.5 36 33 30.5 13 coke 2 2 2 2 2 2 4.5 ore 4 4 3 2 2

[0032] After applying this method, taking the first coke charging as an example, as shown in Chart 2, first charge 2 circles of coke at 30.5° set at the penultimate corner position, then charge 2 circles of coke at 42.5°, and proceed in sequence downward until 4.5 circles of coke at 13° are charged, and the coke charging for one cycle is completed.

[0033] Table 2 Adjusted Coke Charging Matrix

[0034] angle 30.5 42.5 40.5 38.5 36 33 13 coke 2 2 2 2 2 2 4.5

[0035] Then charge the ore. As shown in Chart 3, first charge 2 circles of ore at 33° set at the smallest corner position, then charge 4 circles of ore at 42.5°, and proceed in sequence downward until 2 circles of coke at 36° are charged, and the ore charging for one cycle is completed; the coke and ore together are counted as one ore batch, that is, one charging cycle.

[0036] Table 3 Adjusted Ore Charging Matrix

[0037] angle 33 42.5 40.5 38.5 36 30.5 13 ore 2 4 4 3 2

[0038] In the traditional charging mode, the coke or ore charged into the furnace will impact the original burden surface. Since the charging starts from a large angle on the outside, a large amount of materials at a small angle roll down to the center 4 of the blast furnace, accounting for about 5%. This part of the burden blocks the central gas flow and affects the smooth operation of the blast furnace. After applying this method, the ore starts charging from the smallest angle and the coke starts charging from the penultimate angle, and then charges from the outside to the inside, which is equivalent to forming a coke (ore) dam on the inside, which can effectively prevent the burden from sliding towards the center 4 of the blast furnace, thus forming a new burden surface shape as shown in Figure 3 The new burden surface has less rolling at the center and will not affect the central gas flow of the blast furnace, thus achieving stable central gas flow of the blast furnace and ensuring the smooth operation of the blast furnace.

[0039] All matters not detailed in the present invention are well-known technologies.

[0040] The embodiments described above are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for distributing stabilizing the charge level of a blast furnace, characterized in that: It includes the following steps: Step 1: Determine a suitable burden distribution matrix according to the smelting requirements of the blast furnace, including the starting angles of ore and coke burden distribution, the angular difference, the burden distribution ratio of each angular position, the presence or absence of central coke addition and the specific coke addition amount, and the ratio of ore and coke charged into the furnace per batch; Step 2: Before burden distribution, pressurize the bunker once with semi-clean gas and then pressurize it twice with nitrogen. When the pressure in the bunker is greater than the top pressure of the furnace, start the burden distribution chute to enter the rotating state; Step 3: Adjust the burden distribution chute to the predetermined first burden distribution angle, and then open the lower seal valve and the charging gate in sequence. The burden slides down along the chute into the blast furnace. After the burden distribution at the first angle is completed, adjust it to the second angle for burden distribution, and so on until the entire burden distribution is completed; among them, the coke starts to be distributed from the penultimate burden distribution angular position in one burden distribution cycle, and then is distributed from the outside to the inside according to the remaining angular positions in the cycle; the ore starts to be distributed from the smallest burden distribution angular position in one burden distribution cycle, and then is distributed from the outside to the inside according to the remaining angular positions in the cycle.

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