JPH02166208A - Furnace top charging method in bellless blast furnace - Google Patents

Abstract

PURPOSE:To eliminate deviation of raw material distribution in a furnace by arranging plural pieces of furnace top bunkers in parallel in a bellless blast furnace and making variation of the cycle for charging the raw material. CONSTITUTION:Three furnace top bunkers L, M, N are arranged in the bellless blast furnace and the number of times for charging within the charging cycle for coke (C) and ore (O) to each bunker, is made to two times (a), four times (b) and five times (c), and in the one cycle, each bunker L, M, N, has different phase, respectively, but receives C and O under the same rotation to make discharge of them. By this method, even if the deviated flow is developed with each bunker L, M, N, the raw material distribution in the furnace is made uniform to each direction with one cycle.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a furnace top painting method for a bellless blast furnace that reduces the distribution deviation of the contents in the furnace in the circumferential direction within the furnace. 1. FIG. 2 is a longitudinal cross-sectional view of the top of the blast furnace, showing an example of the occurrence of ore/coke (0/C) distribution deviation in the circumferential direction inside the blast furnace, which is caused by charging raw materials into the blast furnace.

Material charging in a conventional blast furnace is performed using a plurality of furnace top bunkers 1.2 installed oppositely, a vertical chute 3, and a turning shoe 1-4 capable of changing direction.

Depending on which top bunker 12 the raw material passing through the vertical shor 1-3 is to be discharged from, different positions within the vertical shor 1 are selected as falling routes 1~, resulting in drifting of the flow and dispersing the inside circumference of the furnace. This causes a distribution deviation in the direction. In other words, since the falling field 14 falls at different positions on the rotating chute 4, the difference in drift is due to the difference in the drifting distance of the upper shoe 1, which fluctuates as d, d2. Tanu travel time, Si1-
1. The falling velocity of the raw material leaving 1. and the trajectory of the falling material change, and eventually the deposition position in the furnace changes, causing the distribution deviation of the charge in the direction of the furnace circumference in the charge layer, especially in the profile shown in Figure 2. This results in a deviation of O/C component 7↑j as seen in .

As can be seen from the above explanation, if ore is cut from one of the two top bunkers 1 and 2 and coke is cut from the other, and this continues alternately, this causes a large deviation in the O/C distribution in the circumferential direction. becomes.

In order to solve these problems, Japanese Utility Model Publication No. 59-5725 discloses a charging device in which a single hopper having a discharge port is disposed vertically on the central axis of the furnace. Although this device eliminates the unbalance in the circumferential direction, the charging speed decreases. Furthermore, since the height of the device increases, there is a problem in that the equipment cost increases.

Further, in Japanese Patent Publication No. 61-30993, a cut gate is provided to restrict the flow in the vertical chute so that the raw material falls onto the central axis of the furnace. In JP-A-53-102808,
A method is disclosed in which a cone is installed at the top of a vertical chute to prevent drifting. All of these techniques attempt to control the falling trajectory of the raw material by significantly narrowing the flow path through which the raw material falls.

[Problem to be Solved by the Invention 1] In the method of adding a device to prevent uneven flow to the falling flow path of the raw material, it is not easy to completely prevent the distribution deviation in the furnace, and it is not easy to completely prevent the distribution deviation in the furnace. Adding a "cut gate" causes the problem of creating a shelf on the cone.In other words, in order to effectively drop the raw material on the concentric axis, the flow must be significantly reduced so that the raw material flows through the falling channel in a clogged state. It is necessary to narrow the channel. Therefore, if the moisture content of the raw material fluctuates and the flow of the raw material becomes poor, clogging will easily occur, making it difficult to stably control the charging of the raw material.

The present invention does not provide a drift prevention device in the flow path of the raw material, but rather changes the raw material charging cycle to eliminate the distribution deviation in the furnace.

[Means for Solving the Problems 1] The present invention provides three furnace top bunkers in parallel in a bellless blast furnace, and charges the number of times in one raw material charging cycle to 2 times, 4 times,
Furnace Y of a bellless blast furnace characterized by or 5 times
This is a method of chastity insertion.

This will be explained in more detail with reference to FIG.

FIG. 1 schematically shows the plane of three furnace top bunkers arranged in parallel. C10 that enters bunkers L, M, and N when the number of charging cycles of coke (C) and ore (0) is set to 2.4 and 5 for three bunkers M and N, respectively. becomes as follows.

(a) If the number of times of charging is 2 times, Bunker charge It L C0 M QC N C0 (b) If the number of times of charging is 4 times, Bunker charge I II III L C00 M CC0 N 0CC (c) When the number of charging is 5 times, Bunker Charge I II III L COC M C00 N OCO [Function] There are three bunkers, M and N, and C and 0 are charged into it.
If the combination is 24.5 excluding 3 as shown in FIG. 1, each bunker receives and discharges C and O the same number of times in one cycle, although the phases are different from each other. Therefore, even if there is a drift due to each bunker at each charging time, the distribution of people produced in the furnace is homogenized in each direction in one cycle.

Furthermore, the reason why the number aEl of the furnace top bunker is set to three is as follows. Usually, two furnace top bunkers are installed diagonally at 180 degrees, and are symmetrical with respect to the discharge direction. 2
Charging 3 times/cycle in 1 bunker makes the distribution of C10 fraction uniform, but the quantitative non-uniformity is 180
Every degree remains. On the other hand, if three to four furnace top bunkers are provided, the non-uniformity will be eliminated every 12'0 degrees and every 90 degrees.

On the other hand, in order to install four bunkers at the top of the furnace, the installation of the bunkers at the top of the furnace requires space and difficulty in fitting the discharge valve, resulting in excessive equipment costs. In addition, with two bunkers, the number of times of charging is limited, and it becomes difficult to achieve C↓010↓ (one charge of coke and two charges of ore) during high production. For the above reasons, the number of furnace top bunkers needs to be three.

Compared to charging number 2 (C↓0↓) (1 coke charged, 1 ore charged), charging number 4 (CIC↓O↓0↓) (2 coke charged, 2 ore charged) is more. In other words, it is possible to use different charging materials for the first and second coke charging C1, and for example, the first coke charging C↓ It is possible to reduce the cost of raw materials by selectively using coke with high particle size and low quality coke for the second coke charging C↓.The same applies to ore.

Charging number 5 (C↓C↓O↓0↓O1] (2 charges of coke, 3 charges of ore), or (Ci CL C1OLO↓
) (3 charges of coke, 2 charges of ore) is desirable as a charging method, but it has the problem that depending on the production volume, the number of times of charging is reduced by increasing the number of times to 5.

In order to exhibit such multi-functionality, it is more desirable to have at least 3 bunkers and to charge 4.5 times.

[Example] In a blast furnace having a furnace capacity of 4300 m', the present invention was carried out in which the number of times of charging in one cycle was set to four.

FIG. 3('b) shows the change in zero deviation of the eight skin flow thermometers 6, which represents the uniformity in the circumferential direction of the upper part of the blast furnace 5 shown in FIG. 3(a).

After implementing the present invention, the deviation decreased rapidly and became about 1/3. Furthermore, as shown in Figures 3 (b'), (C), and (, d), the fluctuations in temperature and [Si] decreased as the number Z decreased, indicating that the nonuniformity in the circumferential direction was resolved. I understand. In addition, since fluctuations in hot metal temperature have been reduced, it has become possible to lower the average hot metal temperature, and the hot metal temperature has decreased to about 1493°C. As a result, [Si] decreased by 0.2%, which has a significant economic effect.

[Effects of the Invention] According to the present invention, it is possible to eliminate the non-uniformity of temperature in the circumferential direction of the blast furnace, which is peculiar to bellless blast furnaces, and as a result, it is possible to reduce the deviation of [Si] in the hot metal and the temperature of the hot metal from tap to tap. It can be resolved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the contents of a cycle in an embodiment of the method of the present invention, FIG. 2 is a longitudinal sectional view of the vicinity of the top of a bellless blast furnace, and FIG. 3 is a graph showing the effects of the present invention. ■, 2... Furnace top bunker 3... Vertical chute 4
...Swivel chute 5...Blast furnace 6...Skin flow thermometer, M, N...Bunker C...Coke O...
・Ore extraction person Kawasaki Steel Co., Ltd.

Claims (1)

[Claims] 1. A top charging method for a bellless blast furnace, characterized in that three top bunkers are provided in parallel, and the number of charging times in one raw material charging cycle is set to 2, 4, or 5 times. .