JPH01201405A - Method for intermediate repairing in blast furnace - Google Patents

Abstract

PURPOSE:To execute intermediate repair as remaining the contents in a blast furnace for short term by stopping a blow after descending the contents in the furnace to level below tuyere, leveling only hilly remained coke at circumference near the tuyere and forming in order water granulated ballast coating layer and concrete seal on this. CONSTITUTION:At the time of repairing the inner part in the blast furnace 1 as remaining the contents 3, 4 in the furnace bottom, the blow is stopped after descending the contents 3, 4 till reaching to the tuyere level A. Successively, only the hilly remained coke 4 at circumference near the tuyere 5 is leveled and on this remained coke 4, the coating layer of the water granulated ballast 7 is formed. Further, on this coating layer, the concrete matte 6 is formed with the concrete matte working process. By this method, coke discharging work is simplified and the repairing operation term of the blast furnace is shortened and the labor is saved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intermediate blast furnace repair method for repairing the inside of a blast furnace while leaving the contents inside the blast furnace.

[Conventional technology]

Normally, during operation, a blast furnace is filled with ore, coke, etc., and hot metal, slag, and red-hot coke remain in the lower part of the furnace body (hearth section, morning glory section). The inside of the blast furnace is high temperature and has a strong reducing atmosphere. therefore,
When attempting to repair the blast furnace main body, it is necessary to cool the inside of the furnace and to discharge and remove the filling material.

In the case of this method of refurbishing the blast furnace main body, it is necessary to dismantle and remove not only the furnace wall section at the bottom of the blast furnace which has reached the limit of deterioration, but also other parts of the furnace body which are less deteriorated. The reality is that the furnace body would eventually have to be completely dismantled due to the exposed parts.

Therefore, by partially renovating only the lower part of the shaft, which is the most severely damaged and aging part, in a short period of time, we can reduce the production downtime of the blast furnace during the refurbishment period, suppress the impact on other processes, and reduce equipment refurbishment costs. A technology was developed with the aim of restarting blast furnace operations (Japanese Unexamined Patent Publication No. 5
(See Publication No. 7-2809).

This technology is an in-furnace seal construction method that forms a layer of slag-like powder over the contents of the blast furnace, and then casts a concrete partition plate on top of it to install scaffolding for repair work. When actually doing this, the contents are reduced to the bottom of the shaft, openings are made in the furnace wall and shell, and the contents (
The amount of the contents is further reduced to a predetermined level by scraping out the coke), and then the entire surface of the contents is leveled. Then, slag-like powder is charged on top of it to level the surface, and then concrete is placed on top of it.

[Problem to be solved by the invention]

According to this technique, it is necessary to create an opening in the steel shell in order to scrape out the coke that remains in the shape of a hill after the scale reduction. As a result, it will be necessary to close the openings in the steel shell at the start of operations, prolonging the period of repair work. In addition, the time wasted due to the work of scraping out a large amount of coke cannot be ignored.Furthermore, there is work to level the entire surface of the contents, but it is extremely difficult to perform this work when no one can enter the high-temperature blast furnace. dangerous and difficult. Another option is to attach a scraping bar to the tip of a bulldozer and scrape out the residual coke from the blast tuyere, but in this case, the bulldozer is placed around the tuyere and the work space for scraping out is quite large. The reality is that it cannot be an effective solution because it is necessary.

In view of this situation, the present invention aims to provide an intermediate blast furnace repair method that can significantly shorten the period of repair work after content reduction.

[Means to solve the problem]

The first intermediate repair method of the present invention, as shown in 1M,
First, the contents 3.4 are reduced in size until they reach the tuyere level A and then blown off. Next, as shown in Fig. 2, the zero-order leveling is performed to smooth only the vicinity of the tuyere 5 of the hill-shaped residual coke 4 that is the content.
Fig. 3 fa+, (as shown in bl, residual coke 4
A covering layer of granulated ballast 7 is formed on top, and concrete sealing is performed on the covering layer using the concrete mat construction method.

The second intermediate blast furnace refurbishment method of the present invention reduces the contents 3.4 to the level below the tuyere, as shown in Fig. 5, when renovating the inside of the blast furnace while leaving the contents at the bottom of the blast furnace. The method is characterized in that heat is radiated from the contents 3 and 4 by blowing and forming a coating layer 16 of sand on the mound-shaped residual coke 4 in the furnace.

[For production]

In the first method, the contents 3 and 4 are placed at the subtuyere level A.
In order to level out only the area near the tuyere 5, no openings were provided in the furnace wall 2 and the shell l', and people were able to remove the residual coke 4 from the tuyere 5 with debris outside the blast furnace. Just scrape out a small amount.

This simplifies the coke discharge work, which conventionally involved a large amount of work, shortens the repair work period, improves work safety, and saves labor.

After scraping out the residual coke 4, next, a covering layer is formed on the residual coke 4 using granulated ballast 7 and concrete sealing is performed using the concrete mat method. All concrete pouring can be performed from the tuyere 5, and safety and labor savings in the hearth bottom sealing work are realized without setting up large equipment such as a hoist.

Furthermore, as shown in FIG. 4, a donut-shaped flant portion 9 is formed in the vicinity of the furnace wall 2 even after concrete sealing. The flant portion 9 serves as a space for transporting scaffolding materials for furnace wall repair from the tuyere 5, and also enables stable installation of the scaffold 10 there, facilitating repair of the lower part of the furnace body. Furthermore, the middle and upper part of the furnace body can be repaired by assembling a scaffold 10 on top of the hill-shaped residual coke 4 as shown in FIG.

In the figure, 11 is a gas vent pipe, 12 is a stave cooler, and 13 is a tap hole.

In the second intermediate blast furnace repair method, residual coke 4 is completely covered by scattering sand into the blast furnace 1.

In this way, most of the covered area is cooled down to a level where people can enter, and a scaffold 10 can be temporarily erected from there to repair the furnace wall. Therefore, the furnace wall can be repaired without placing concrete on the residual coke or securing space for a bulldozer around the tuyere, which is the case in the past, and the construction period can be significantly shortened. Can be done.

〔Example〕

Embodiments of the present invention will be specifically described below based on the drawings.

First, an example of the first method will be described.

As shown in FIG. 1, the content 3.4 of the blast furnace 1 is reduced in size until it reaches below the tuyere level A and is blown off.

This is done when the air blows up from the stop tuyere 5.
The contents consist of hill-shaped residual coke 4, hot metal and molten slag 3, and as shown in FIG.
Scrape it out from the tuyere 5 using a No. 4 or similar tool, and level only the area around the tuyere 5 to make it flat.

Subsequently, as shown in FIG. 3, the granulated ballast 7 is inserted into the furnace through the tuyere 5, and a coating layer is formed on the residual coke 4. The layer is
This is a layer that radiates heat and removes generated gas from the contents 3.4 present at the bottom of the furnace. For degassing, degas vibrator 11
It is sufficient to bury the tube in the residual coke 4 and allow the tube end to come out of the furnace through the tuyere 5.

Once the P1 layer is formed, the contents-3 and 4, including the coating layer, are then concrete-sealed. In this case, concrete mat construction method will be adopted. In other words, this construction method is
It uses a bag-shaped frame made of synthetic fiber fabric.
As shown in Figure 3fa), (bl), insert the concrete matsuturo through the tuyere 5, and stretch the mat by pulling the ends of the matsuturo from several tuyeres 5... with threads 15, etc. Next, concrete is poured into this concrete matsutro using a pump truck and cured for a necessary drying period.A concrete supply hose 8 is connected to the concrete matsutro to connect the inside of the mat and the concrete supply source. We are contacting you.

The granulated ballast used as the coke coating layer in the first method may be granulated slag, but it has a larger unit weight and is denser than granulated slag, and as a result has excellent supporting capacity, and also has gas sealing and heat insulation properties. The slow-cooled slag is also suitable for these purposes. When using this slowly cooled slag, for example, the structure of the coating layer is changed from below to the snow mass balance of slowly cooled slag (
14M (approximately 150 dragons thick) of grain size 20 to 40 fins, and 14 rrr (approximately 1
50mm thick), and a concrete layer of about 300mm thick is formed on top of it. Needless to say, the granulated ballast used may be granulated slag other than slow-cooled slag, and there are no particular restrictions on the amount, thickness, grain size, etc. of the ballast.

A method for charging the granulated ballast into the furnace includes, for example, a method in which it is pumped through a tuyere using a tank truck. According to this method, it is possible to uniformly pour the liquid onto the contents. However, other methods may be used, such as charging from the large bell of the blast furnace.

The concrete mat used in the first method is
For example, it is a bag-shaped frame made from coarse synthetic fiber fabric with high strength. The cloak fabric may be of any material as long as it can withstand the tension after concrete is poured, such as high tensile canylon fabric.

Next, an example of the second method will be described.

As shown in FIG. 5, the content 3.4 of the blast furnace 1 is reduced in size and blown until it reaches below the level of the tuyere 5.

This is done when the air blows up from the stop tuyere 5.
The contents are hill-shaped residual coke 4 and hot metal and slag 3
Consisting of

After the blast furnace 1 is stopped, sand is then spread over the residual coke 4 to form a coating layer 16 of sand.

Due to the formation of a dense coating layer 16 of sand, the content 3.4
is radiated heat. The ambient temperature above the coating layer 16 is lowered by the heat radiation of the contents 3.4, and when the temperature has cooled to a temperature that does not interfere with work, a scaffold 1O is installed and the lower part of the furnace body is repaired.

When forming the coating layer 16 with sand, it is best to scatter the sand from the top of the furnace in order to spread the sand to a substantially uniform thickness on the hill-shaped residual coke 4 remaining in the furnace. Since a device for charging raw materials is installed, this may be used, or a new temporary chute or the like may be provided.

If the thickness of the sand coating layer 16 is 300°C or more, the ambient temperature can be adjusted to the temperature at which a person can enter the furnace (80 degrees for the soles of the feet, 20 degrees for the overhead).
Test results have shown that the temperature can be lowered to 40°C. However, if it is too thick, it will cover the opening of the tuyere 5 and cause problems such as making it impossible to enter the furnace, so a thickness of about 300 to 500 mm is appropriate.

Next, the results of implementing the second method will be described. Figure 6 shows the scale of the furnace and the sand spreading situation, and Figures 7 (a) and (b) show the specific procedure for sand spreading.

The second method involves first blowing the blast furnace when the content 3.4 reaches the tuyere level, and then
As shown in FIG. -24 was applied uniformly in the radial direction of the furnace. As a result, the amount of spraying was 25 rrr for 3 skips, and the working time was 3 hours.
Sand was thrown in from chute 27 of φ. The amount of spraying was 11 d, and the working time was 2 hours. Therefore, the total loss amount is 3
6/, total working time was 5 hours.

After the spraying was completed, the top of the contents was evenly covered with sand to a thickness of 300 fi, except for some steep areas, as shown in Figure 6.

FIGS. 8(a) and 8(b) show the measurement results of the furnace environment (atmosphere temperature) after sand dispersion. As shown in FIG. 8(a), the measured temperature was selected at positions T and T4 based on the operator 17. That is, T, , and T are the temperatures inside the sand, that is, the sole of the foot, in the completely sealed and incompletely sealed states, respectively, and T.

$74 indicates the temperature at 2 m above the sand, that is, in the state of complete sealing and incomplete sealing above the head. In addition, 18 in the figure indicates the flame.

As shown in Figure 8 (b), the temperature at the position shown in Figure 8 (a) is T'-y = 750°C to 917°C in the case of an incomplete seal at the sole position when the worker enters the area. However, in the case of a complete seal, from the 4th day to the 111th day, the temperature was approximately T = 80°C, and from the 111th day to the 144th day, although it increased slightly, the average temperature was 85°C, and in the overhead position, in the case of a complete seal, the temperature was 4 From Ts -40"C on the 144th day, an almost constant falling state was obtained, and the average temperature on the 144th day was 36"C.In other words, in the area uniformly sealed with sand, the worker could not stand up. However, the hills of residual coke do not have a uniform slope, and even if the steep parts cannot be sealed, the parts other than the steep parts can be uniformly covered with sand.

As described above, by spreading sand inside the blast furnace, most of the parts that have been completely sealed can be accessed by people, and temporary scaffolding can be erected from there to repair the furnace walls. However, m-carbon gas under the sand seal leaks through the sand particles,
Since the gas concentration is 50 ppm or more, the operator 17 must wear a gas mask 19 as shown in FIG.

According to the second method, the furnace wall can be repaired without placing concrete on the residual coke as in the conventional method, and the construction period can be significantly shortened.

In other words, in conventional concrete pouring,
30 (requires thickness of 1+s, hearth diameter (inside tuyere) 1
15~25r+ in a 0m blast furnace? You need to hit it to a certain extent. In order to pour this concrete, it is necessary to scrape out the residual portion remaining under the tuyere and lay something like a sealing steel plate on top of it to prevent the moisture in the concrete from sinking. Concrete will be poured for the first time.

It takes about five days to place such concrete, and it takes one day to crack the concrete to ensure ventilation before reheating. However, according to the second method, the labor and time required for these are unnecessary.

〔Effect of the invention〕

As explained above, according to the first method of the present invention,
The coke discharge work, which conventionally involved a large amount of work, is simplified, making it possible to shorten the blast furnace renovation work period and save labor. Furthermore, safety and labor savings in the furnace bottom sealing work can be achieved without setting up large-scale equipment.

Further, according to the second method of the present invention, the furnace wall can be repaired without placing concrete on the residual coke as in the conventional method. Therefore, the construction period can be significantly shortened, and there is no need to set up large-scale equipment, and the bottom sealing work can be carried out efficiently and economically using existing equipment.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the reduced length stop of the blast furnace in the first embodiment of the present invention, FIG. 2 is a perspective explanatory view showing the coke leveling process in the first embodiment of the present invention, and FIG.
Figures (al and bl are respectively a perspective explanatory view and a partial sectional view showing the concrete sealing process in the first embodiment of the present invention, and Figure 4 is a state of scaffold assembly performed based on the first embodiment of the present invention. FIG. 5 is a cross-sectional view showing the state of scaffold assembly carried out based on the second embodiment of the present invention, and FIGS. 6 to 8 are explanations of the implementation results of the second embodiment of the present invention. Figure 6 shows the sand distribution situation, Figure 7 (
A) (B) is the specific method of introducing sand, Figure 8 (A) (B)
shows the change in the temperature of the furnace atmosphere after sand dispersion, respectively. In the figure, 1: blast furnace, 3: hot metal and slag, 4: residual coke, 5: tuyere, 6: concrete mat, 7: granulated ballast, 16: coating layer of sand. Figure 1 Figure 2 Figure 3 Figure a Figure 3 Figure 5 Figure 6 (A) aq- Figure 7 Figure 8 (A) Number of days that have passed since the opening of the barley (mortar)

Claims (1)

[Claims] 1. When repairing the inside of the blast furnace with the contents remaining at the bottom of the furnace, the contents are reduced to the level below the tuyere and stopped, and only the hill-shaped residual coke around the tuyere area is removed. A method for intermediate refurbishment of a blast furnace, comprising leveling the remaining coke, forming a coating layer of granulated ballast on the residual coke, and performing concrete sealing on the coating layer using a concrete mat construction method. 2. When renovating the inside of the blast furnace with the contents remaining at the bottom of the blast furnace, the contents are reduced to the level below the tuyere and stopped, and a coating layer of sand is placed on top of the hill-shaped residual coke inside the furnace. A method for intermediate refurbishment of a blast furnace, characterized in that the contents are sealed by forming the contents.