KR20010063513A - Method for working in the blast furnace to improve the condition under the high pulverized coal injection - Google Patents

Abstract

PURPOSE: A blast furnace operating method is provided to improve the first and second stages of the lower part of the body of the blast furnace, and the air permeability resistance index by removing non-burned carbon in which pulverized coal injected into the blast furnace is not completely burned, but piled up in the raceway. CONSTITUTION: In a blast furnace operation method comprising the processes of alternately charging sintering ore and cokes into the burden charging zone that is divided into 10 notches according to the tilting angle of a charging rotary chute from the furnace top, and injecting pulverized coal along with a high temperature air from a tuyere, the method further comprises the process of removing non-burned carbon that exists in the raceway which is generated during the injection of highly pulverized coal by charging small sinter comprising FeO into the wall part of the blast furnace.

Description

Method for working in the blast furnace to improve the condition under the high pulverized coal injection}

The present invention relates to a blast furnace operation method for preventing deterioration caused by the charging of the blast furnace in operation, and in particular, to remove the unburned carbon accumulated in the raceway without burning all the pulverized coal injected into the blast furnace 1 The present invention relates to a blast furnace operation method for improving the stage, the lower body of the second stage, and the ventilation resistance index.

In general, in the blast furnace operation, as shown in Figure 1, the raw material and the sintered ore cut out from the raw material bin (1-21,1-22) is transferred to the top of the blast furnace through the charging belt conveyor (1-14) The hopper is stored in the hopper 1-7 through the flap gate 1-9 and the hopper upper sealing valve 1-8. Then, the sintered ore and the coke are uniformly charged and distributed in the blast furnace through the turning chute 1-6 controlled at each set notch tilt angle.

That is, coke (1-13) having a particle size of 25 mm to 75 mm is charged, an allergic sintered light (1-15) having a particle size of 12 mm to 50 mm is charged, and a small sintered light (1-16) having a particle size of 5 mm to 12 mm is charged. do.

At this time, the coke 11-1 is uniformly charged in the radial direction of the blast furnace to form the soft fusion zone 1-1 under the blast furnace. In addition, a small sintered ore (1-16) having excellent reducibility and breathability is mounted on the furnace wall to induce furnace protection by alternately charging at the upper part of the blast furnace to form a layer (TERRICE). Hot air is blown through the blast furnace (1-4) to produce a molten iron (1-2) by causing the reduction and melting of iron ore.

The high pulverized coal blowing operation of such blast furnaces requires stable profile in the blast furnace to improve gas flow, that is, the air permeability as a whole, to stabilize the furnace situation, and economic operation is possible only when iron ore is reduced and melted. Higher and longer life of the blast furnace.

In other words, in order for the profile to be stable and the gas flow and breathability to be smooth, the wind entering the blast furnace through the vent holes (1-4) must be stabilized so that the temperature at the bottom of the blast furnace is kept constant and the gas flow and aeration resistance indexes are also continuous. It will maintain a stable aging.

In recent years, attempts have been made to increase the amount of pulverized coal injection, but most of the blast furnaces do not sustain the pulverized coal injection in the long term and reduce the amount of blowing because the above-mentioned problems, namely the most important blowing conditions in the blast furnace operation, are not desired. As a result of the operation of controlling the temperature fluctuation and ventilation resistance index of the bottom of the blast furnace caused by the unburned carbon (1-3) remaining in the blast hole due to the injection of pulverized coal, the molten iron production is reduced and the coke is used relatively. It is an uneconomic blast furnace operation.

In other words, if the pulverized coal blown into the blast furnace is not completely burned in front of the tuyere, but unburned carbon exists in the space created by the wind entering the raceway, that is, the blast furnace tuyere, the length of the raceway 6-1 is shortened, thereby causing the tuyere. As the wind enters through the furnace wall rather than toward the center of the blast furnace, as shown on the left side of FIG. 5, in order to protect the furnace body at the same time the temperature of the lower and lower stages of the furnace body rises under the softening fusion zone. The heat loads of the lower and lower stages of the furnace were also increased by considering the temperature difference between the water supply and the drainage of the installed cooling water flow rate.

As a result, the gas passing through the furnace is unstable, and the profile of the furnace is deteriorated, so that the ventilation resistance index, that is, the pressure of the pressure gauge and the wind vent on the upper part of the blast furnace, and the oxygen from the wind reacted with the coke and pulverized coal, The relationship rises sharply and the situation in the furnace rapidly deteriorates.

Therefore, the unburned carbon (1-3) in the raceway (6-1) in front of the tuyere (1-4) cannot be removed and there is a limit to burning all the unburned carbon even if a large amount of oxygen is used to burn the pulverized coal. Therefore, in the case of unburned carbon generated by the injection of high pulverized coal, the effect of preventing a change in the furnace situation is extremely small and thus it is not a fundamental solution.

In order to solve the conventional problems as described above, the present invention, when the unburned carbon deposited on the raceway due to the injection of high pulverized coal during blast furnace operation deteriorates the furnace body bottom temperature and the airflow resistance index, at the same time, the small sintered ore and bustite are charged. The purpose of the present invention is to provide a blast furnace operation method that can remove the unburned carbon of the raceway by maintaining the top of the furnace to stabilize the bottom temperature of the furnace, make the gas flow smoothly in the furnace wall, and maintain the ventilation resistance index.

According to the present invention, in order to achieve the above object, in the blast furnace operation method, when loading by the particle size of the charge without changing the amount of production in the operation under the normal state, by inserting the Bustite in the blast furnace wall portion, the Bustite falls along the blast furnace wall, React with the unburned carbon present in the raceway of the characterized in that to remove it.

That is, according to the embodiment of the present invention, the blast furnace operating method is to remove the unburned carbon generated during the injection of high pulverized coal by using the topless loading device, when the grain size of the sintered crushed by the particle size of the charged by inserting the bustite ore part By removing the unburned carbon by reacting unburned carbon in the raceway with the busstatite ore, it controls the temperature of the lower part of the furnace body and the lower part of the furnace body and improves the ventilation resistance index. .

1 is a charging state diagram of a typical blast furnace charge.

Figure 2 is a schematic diagram showing the drop trajectory of the charge according to the notch from the charging swiveling suit.

Figure 3 is a schematic diagram showing the falling state of the Bustite charged in the furnace wall according to an embodiment of the present invention.

Figure 4 is a table showing a comparison of the charging state of the charge according to the hardness notch number of the charging swiveling chute according to the embodiment of the present invention and the conventional embodiment.

5 is a table comparing the lower body stage 1, the lower body stage 2 and the ventilation resistance index according to the embodiment of the present invention and the conventional embodiment.

<Description of Symbols for Major Parts of Drawings>

1: blast furnace

1-1: Softening Fusion Zone

1-2: molten iron

1-3: Raceway

1-4: Fenggu

1-6: Turning suit

1-16: Busstein

2-1, to 2-10: notch

Hereinafter, with reference to the accompanying drawings illustrating a preferred embodiment of the present invention as follows, the same configuration adopts the same reference numerals.

First, according to an embodiment of the present invention, in order to maintain stable aging even when unburned carbon (1-3) accumulates in front of the tuyere during the operation of high pulverized coal blowing operation, the lower part of the furnace body 1-1 (8-1) and the lower body 2 of the blast furnace The temperature of the stage 8-2 can be controlled and the ventilation resistance index can be kept constant.

In other words, by loading the buste ore at the time of loading by the particle size according to the accumulation of unburned carbon (1-3), it controls the underbody temperature and controls the ventilation resistance index in spite of fluctuations in the furnace situation caused by the accumulation of unburned carbon (1-3). Can be kept low to maintain stable conditions in the furnace.

Therefore, in the blast furnace operating method according to the present invention, the coke (1-13), allele sintered ore (1-15), and small sintered ore (1-16) are sequentially charged from the top to form a layer, and then reduced and melted. In the blast furnace operation to produce molten iron, when the charge is charged by the charging turning chute (1-6) of the bellless charging device, the coke and the allele of sinter are charged and then the Busteite ore and the small sintered ore are charged.

Referring to FIG. 1 again, first, the busstatt is stored under the small sintered ore bin 1-19 of the relay bath bin 1-20, and then the small sintered ore is stored. When the sintered ore is charged, when the contents are discharged from the small sintered ore bin (1-19) of the transit tank bin (1-20), the busite ore under the small sintered ore is discharged first and then the small sintered ore is discharged. do.

That is, the small sintered ore and bustite (1-16, 1-23) on the charging belt (1-14) is loaded in the charging belt as a group and stored in the top hopper (1-7). Even when stored in the top hopper, the Buste ore located in front of the small sintered ore is stored in the bottom of the top hopper. When the mixed loading of the small sintered or the buste ore starts, as shown in FIG. 2, the first turning chute 1-6 and the second notch 2 of the charging turn chute are rotated while the charging turn chute 1-6 rotates. -2) is charged with a Buste ore, and then a small sintered ore.

The mixed charging of such small sintered or bustite ores is continuously charged at each charge. Thus, as shown in the shape of small sintered ore in Fig. 3, the Buste ore reaches the blast hole on the blast furnace wall part.

Since the Bustite ore is characterized by the slowest reduction among iron oxide ores, the ratio of carbon monoxide and carbon dioxide in the blast furnace is almost 50%, and at this temperature, the Bustite ore (FeO) is stable and descends through the furnace walls. . When charged so that the Buste ore is not reduced in the furnace wall, the allele sintered or coke is charged by moving one notch from the furnace wall to the center of the blast furnace, as shown in FIG. In other words, when the small sintered or bustite ore is charged, the charging pattern from the first notch to the fourth notch (2-1 to 2-4) used in the normal operation is used only for the first notch and the second notch. Charge as far from the center as possible.

Thus, as shown in Fig. 5, the furnace body temperature is managed lower than in normal operation to prevent the high temperature gas in the furnace from flowing to the furnace wall as much as possible. In this way, the bustye charged in the furnace wall fall to the tuyere and react with the unburned carbon deposited on the raceway to remove the unburned carbon.

More specifically, as shown in FIG. 4, unlike the notch used in normal operation, it can be seen that, in the case of coke, the number of revolutions is the same while charged by moving one notch from the blast furnace furnace wall to the center.

However, the number of rotations of the coke is set in consideration of the lower body first stage 8-1, the lower body second stage 8-2 and the ventilation resistance index. That is, according to the embodiment of the present invention, by removing the unburned carbon deposited in front of the tuyere by blowing coal fine coal, the lower part of the furnace body 1 stage (8-1), the lower body of the furnace body 2 stage (8-2) and the ventilation resistance index Coke rotational speed (y), which is one of the methods for improving them, is expressed by the following equation.

That is, y = 0.35 x 2-0.20X + 1.23698, where x is the airflow resistance index.

In addition, referring to Fig. 4, the notch of the opposing ore is set in the same manner as in normal operation. Therefore, it is possible to minimize the flow of high-temperature wind from the tuyere to the blast furnace wall portion from the center. If, as shown in Fig. 4, the opposing ore moves 1 notch from the furnace wall to the center as in the coke, the amount of allele ore flowing into the center at the time of charging increases, thereby suppressing the amount of hot gas flowing from the blast furnace to the center. This suppressed gas flows to the furnace wall part.

Therefore, in the case of the present invention, the opposing ore is charged as in normal operation, thereby blocking the gas flowing from the blast furnace center portion to the furnace wall, and allowing the small sintered ore and buxite ore charged by the upper blast furnace charging device to descend directly to the top of the tuyere. Meet Miyeon Carbon deposited on the raceway in front of Punggu.

Referring again to FIG. 4, it can be seen that the notch used for charging the charged material is completely different from the charging type used in the blast furnace operation. That is, in the normal operation state, as shown in Fig. 4, the use notch of the opposing ore and the coke overlap one notch to two notches. However, in the present invention, the use of the opposing ore and coke in three notches overlaps the effect of blocking the flow of hot gas from the center of the blast furnace to the furnace wall.

In the case of the normal operation of the small ore (small sintered ore), the operation mode using the first notch to the fourth notch is most, but in the embodiment of the present invention, the high temperature that enters the tuyere using only the first notch and the second notch. Even if the gas flows into the furnace wall, it is not affected as much as possible.

In addition, in the embodiment of the present invention, when mixing the small sintered mineral (small particle ore) and the beustite ore, the beustite ore goes down to the upper part of the blast furnace in the lower part of the blast furnace, and with the unburned carbon in the raceway in front of the blast furnace. In order to help the reaction, the busting method was used so that Bustite was first loaded into the furnace wall. In order to satisfy this method, when storing small sintered or busite ore in the small sintered light hopper (1-19) of the relay tank (1-20), the bustite is stored under the small sintered light hopper (1-19) and then Store the sintered ore.

Then, when the charge of the charge stored in the small sintered light hopper comes, the beustite ore is discharged first and positioned at the front of the charging belt (1-14), and the small sintered light is placed behind and stored in the charging hopper. Even when stored in the top hopper (1-7), the Busteite ore is stored at the bottom and the small sintered ore is stored on the Busteite ore. When the charging sequence is reached, the charging turning chute (1-6) is rotated to load the Buste ore into the first notch and the small sintered ore into the second notch.

In more detail, the mixed loading of the Buste ore and the small sintered ore charged from the top hopper is charged at every charge, and in order to allow the Buste ore to slowly descend from the upper part of the blast furnace directly to the upper part of the blast furnace. In the present invention, the notch (usually the first notch to the fifth notch) used in normal operation is moved to the center of the notch from the furnace wall and charged, thereby preventing the hot gas from flowing to the furnace wall.

In addition, the opposing ore is charged in the same way as in normal operation, thereby maximizing the effect of reducing the amount of gas flowing into the furnace wall while maintaining the same amount of gas flowing into the blast furnace center.

In addition, the amount of gas flowing from the blast furnace center part to the furnace wall part by using a method in which coke used notch and 1 to 2 notch overlap each other in normal operation so that the allele sintering is charged from the blast furnace center part to the furnace wall part than the normal operation type. Make small.

Since the charging method as described above prevents high temperature wind from entering the blast furnace from flowing from the center of the blast furnace to the furnace wall portion, the rise of the furnace wall temperature is suppressed so that the Bustite ore and small sintered ore descending from the furnace wall of the blast furnace are directly above the blast hole. Until it comes down to solid state.

Accordingly, as shown in FIG. 3, the amount of coke among the charges charged into the blast furnace increases in the center portion, and the flow rate of the gas flowing from the bottom of the blast furnace to the top increases, so that the shape of the softening fusion zone 1-1 is The station is shaped like a "V". This means that the ore coming from the top at the center starts to melt first when compared to the blast furnace height, and the furnace wall begins to melt directly above the tuyere.

In other words, as described above, the furnace condition of the blast furnace is the core of the technology applicable in the present invention. The upper part of the fusion furnace based on the softening fusion zone (1-1) in the blast furnace has solid ore and coke and is softened. The lower part of the fusion zone is the area where the solid contents melt. In particular, when comparing the blast furnace center and the furnace wall portion, there is a solid charge in the furnace wall portion far lower than the center portion.

In order to verify the technical effects as described above, as shown in Figure 5, the data obtained from the various sensors of the blast furnace operation was used and analyzed.

First, in an operation not using busstatite according to the conventional embodiment, when a large amount of pulverized coal is blown, unburned pulverized coal is present on the raceway, and the wind entering through the tuyere does not flow to the center. The wind affects the blast furnace walls at the center, and the hourly calculated by using the water supply and drainage temperature difference of the cooling section cooling water in the lower part of the blast furnace installed to protect the furnace body. It can be seen that the calorific value fluctuates and the ventilation resistance index of the blast furnace is lowered.

That is, when the temperature of the lower stage 1st stage 8-1 and the 2nd stage 8-2 rises, the amount of coke required to produce 1 ton of molten iron increases because the amount of heat in the blast furnace is released through the furnace shell. Increasing results in uneconomical operations. In addition, when the blast furnace temperature rises, the gas from the blast furnace cannot escape to the upper part stably, and the profile of the charges falling from the upper part is disturbed and the internal condition of the furnace deteriorates sharply. As a result, the aeration resistance index deteriorates. As the contents of the charges descending to the lower part become unstable, the contents of the charges deteriorate and the gas rising from the lower part does not rise uniformly and the drift (gas flows into the weak part of the charge layer) occurs, which causes the high temperature of the lower part of the blast furnace. The gas escapes to the upper part of the blast furnace in just a few seconds (the phenomenon that the hot gas from the air blast does not escape uniformly and suddenly rises to the weak part of the charge layer) occurs and the softening fusion zone is destroyed to return to normal operation. It takes a lot of time.

This incidence has occurred more than 10 times in blast furnace operations and may face the risk of re-installation of blast furnace bodies if the return to normal operation is delayed.

As described above, as a phenomenon that is slightly weaker than the instability of the furnace situation, the charges coming from the upper part of the blast furnace may not be lowered for 30 minutes or more, and the entire contents of the charges may be hung in some parts of the blast furnace. Likewise, if it takes a long time, it may develop into the above-mentioned blow.

This phenomenon mentioned above is using coke as a main fuel used in the production of molten iron in the world recently. When the coke plant is deteriorated due to environmental problems, it is difficult to rebuild the plant, and the price of pulverized coal is reduced. Most of the blast furnace operations are increasing the amount of pulverized coal intake because they are much lower than the cost of production.

However, as mentioned above, if a large amount of pulverized coal is blown through the tuyere, it is not burned entirely and is deposited on the raceway in front of the tuyere, as shown in FIG. 5, as shown in FIG. 5. It can be seen that the indexes are significantly different than the operation index according to the embodiment of the present invention.

In more detail, the buste ore charged from the top is charged by the charging method described above so as to descend to the upper portion of the tuyere as solid as possible. By the charging method, the furnace temperature is managed low, and the life of the furnace shell of the furnace wall installed in the blast furnace, the furnace refractory body, and the furnace cooling plate, which is a cooling facility, can be reduced, and the amount of heat required for the blast furnace operation can be reduced.

By this way, the Busteite ore coming down the furnace wall is removed by reaction with unburned carbon in the raceway in front of Punggu, and as a basis for knowing that the unburned carbon is removed, it is determined by the results of operation after applying the technology of the present invention. to be. That is, referring to Figure 7, according to the embodiment of the present invention, after loading the busteite ore, it can be seen that the temperature of the lower stage first stage 8-1 and the second stage 8-2 is lowered. Also, it can be seen that the airflow resistance index has also decreased.

Therefore, if the furnace bottom temperature rises or the aeration resistance index deteriorates without the external factor during the operation of the high pulverized coal blowing operation, it is determined that the unburned carbon is not burned when the pulverized coal is blown and the technology according to the present invention is applied.

In addition, another effect that can be obtained by applying the technique according to the present invention is that the busted ore charged from the top of the descent fall to the lower part of the tuyere to react with the fine powder or unburned carbon existing between the exit port in the tuyere to improve the flow of the melt As a result, the temperature of the blast furnace floor increases.

As described above, the present invention has the effect of improving the productivity and securing the blast furnace life by keeping the blast furnace temperature and the ventilation resistance index stable at all times as compared with the conventional normal operation method when blowing coal dust.

In addition, in order to maintain the overall furnace temperature, by reducing the amount of heat discharged out of the blast furnace, it is possible to reduce the amount of coke and fine injection required for the production of molten iron and to solve the unstable unstable. Therefore, a more stable high pulverized coal injection operation is possible.

Due to this effect, when the embodiment of the present invention is applied even when blowing coal dust, the temperature of the lower stage first stage 8-1 and the second stage 8-2 is controlled, and the remaining furnace wall temperature is lowered and aeration Due to the stability of the resistance index, it is possible to contribute greatly to blast furnace productivity and longevity.

The foregoing is merely illustrative of the preferred embodiments of the present invention and those skilled in the art to which the present invention pertains may make modifications and changes to the present invention without departing from the spirit and gist of the invention as set forth in the appended claims. It should be recognized.

Claims (5)

In the blast furnace operation method in which sintered ore and coke are charged alternately from the top into the charge charging zone divided into 10 notches according to the tilt angle of the charging turning chute, and the high temperature wind and pulverized coal are blown from the tuyere. Blast furnace operation method characterized in that by inserting a small particle containing a beustite ore in the blast furnace wall to remove the unburned carbon present in the raceway generated when blowing the fine pulverized coal. The blast furnace operation method according to claim 1, wherein the bus-site ore is charged to the blast furnace wall after the coke and the allelic sintered ore are charged and before the small sintered ore is charged. The rotational speed (Y) of the charging swiveling chute charging said coke is a following formula, Y = 0.35 × 2-0.20 × X + 1.23698, And wherein X is a ventilation resistance index. 4. The blast furnace operating method according to claim 3, wherein the coke is charged from 2 notches to 6 notches. 5. The blast furnace operating method according to claim 4, wherein the allied sintered ore is charged from 4 notches to 9 notches.