JP2955434B2 - How to detect blast furnace core renewal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the renewal of a blast furnace core as an index for evaluating the in-furnace activity based on the state of coke in the blast furnace core.

[0002]

2. Description of the Related Art The core of a blast furnace is formed by depositing coke particles, and the charge in the shaft portion passes through the furnace in several hours, while the core of the blast furnace takes several days to several weeks or more. It is presumed that coke is replaced in short. There is no problem as long as the high-temperature gas inside the furnace is sufficiently flowing through the furnace core, and there is no problem.However, the permeability of the furnace core deteriorates due to rapid reduction of coke particles and other factors. When the gas becomes difficult to flow, the temperature of the furnace core part starts to decrease locally or entirely, and coke breeze, unburned char, ash, etc. stay in the furnace. Hot metal and slag increase in viscosity and stay in the furnace core, resulting in cooling of the lower part of the furnace.

[0003] It is important to directly grasp the state of the furnace core from such a situation. For this reason, a tube is inserted into the furnace core to sample the contents, and the state of coke and slag, the rate of coke breeze, and the like are determined. Investigations have also been made. However, there is no way to directly measure the temporal change of the core coke, and it is only estimated that it takes about 5 to 14 days to replace the entire core coke, depending on the furnace conditions, depending on the furnace conditions.

Japanese Patent Laid-Open No. 2-9300 discloses a method of indirectly estimating the core coke renewal by calculation from such a situation.
No. 8 has been proposed. This is to calculate the tuyere blast conditions and the iron storage level as parameters. However, the iron storage level is difficult to measure directly and must be estimated from the hot metal output.Furthermore, there are fundamentally the effects of the permeability and liquid permeability of the furnace core, and the renewal of the furnace core is performed using only these parameters. Accurate estimation is difficult.

[0005]

When unburned char or slag accumulates in the core of the furnace and the furnace condition becomes poor, a method of directly injecting gas into the core of the furnace to perform a direct treatment has attracted attention. However, this also assumes that the state of the furnace core is accurately grasped. In particular, by dynamically grasping the behavior of coke, it is possible to easily perform an appropriate treatment in accordance with the state of the furnace core, and further confirm the effect of the applied treatment. The present invention provides a method for checking the renewal status of core coke by direct means.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a double pipe consisting of an outer pipe and an inner pipe having open ends is inserted into a core of a blast furnace when the blast furnace is shut off. Thereafter, only the inner pipe is withdrawn, the inner pipe separately charged with tracer coke is inserted into the outer pipe, and the outer furnace inside the inner pipe charged with the tracer coke is held down by a stopper to stop the inner pipe and the outer pipe. A method for detecting the renewal of a blast furnace core, wherein a pipe is pulled out to leave only the tracer coke in the furnace, and after a lapse of time, the state of the tracer coke is investigated by sampling.

[0007] Further, the present invention is characterized in that pitch coke, formed coke or high temperature carbonized coke is used alone or as a mixture with ordinary coke as a tracer coke. It is also characterized in that refractory granules are mixed with coke for use as tracer coke.

[0008]

According to the present invention, tracer coke is inserted into the core of a blast furnace. For this reason, a double tube is inserted into the tuyere at the time of the cold. The double pipe is composed of an inner pipe and an outer pipe made of a metal pipe having an open end. That is, the inner tube and the outer tube are not in close contact with each other and can be freely inserted and removed, and a metal tube is appropriate in terms of strength. Further, since the metal tube is not placed in the furnace for a long time, it is not usually necessary to perform water cooling.

FIG. 1 is a sectional view of a lower portion of a blast furnace showing a method of detecting the renewal of a blast furnace core according to the present invention, and shows a state in which a double tube 1 composed of an inner tube 2 and an outer tube 3 is inserted from a tuyere 4. ing. In the figure, 5 is a furnace core, 6 is a ventilation branch pipe, and 7 is an insertion cart.
When only the inner tube 2 is extracted from this state, coke in the tube is taken out together with the inner tube, and the outer tube 3 remains inserted in the furnace as it is. Therefore, insert the inner tube prepared separately packed with tracer coke into the outer tube, press the outside of the furnace inside the inner tube with a stopper, and leave the contents as it is so that the outer tube and the inner tube When pulled out of the furnace, only the tracer coke filled in the inner tube remains in the furnace.

FIG. 2 is a sectional view of the lower part of the blast furnace showing a state in which the inner pipe 2 loaded with the tracer coke and the stopper 9 are inserted into the outer pipe 3. FIG. 3 is a cross-sectional view showing a state in which the stopper 9 is inserted into the inner tube 2. The stopper 9 is attached to the tip of a long stopper support rod 10,
It slides in the inner tube without resistance. In FIG. 2, the loading cart 7 includes an inner tube 2, an outer tube 3, and a stopper support rod 1.
0 can be arbitrarily clamped or released and moved. Stopper support rod 10
Is fixed by a fixing stand 11, and for the loading cart 7, the stopper support rod 10 is opened to clamp the inner pipe 2 and the outer pipe 3, and when the loading cart is retracted, the tracer coke is put into the furnace. Can be left. When the distal ends of the inner tube 2 and the outer tube 3 have retreated to the stopper 9, the stopper support rod 10 is also clamped to the loading cart 7, the fixing stand 11 is removed, and the loading cart is further retracted, the inner tube, The outer tube and stopper can all be taken out of the furnace.

In this state, after the inlet 8 is closed and air is blown from the tuyere to operate the blast furnace, the sampler is inserted into the furnace at the next time when the wind is shut off to collect the tracer coke that has been previously placed. The extraction of tracer coke can be performed by simply pushing a pipe into the furnace.However, according to the method of using the double tube of the present invention described above, first, the tracer coke that has been previously introduced is collected and extracted in the inner tube, and then the tracer coke is extracted. A new tracer coke can be inserted into another inner tube and used for the next measurement. The position where the tracer coke is collected may be the same as the position where the tracer coke was inserted first, or may be a position lower than that. The tuyere part is the easiest for the insertion position of the tracer coke as an existing opening, but there is a case where there is not much left when collecting from the same position after a long time because the tracer coke itself gradually moves down . Therefore, it may be preferable to collect the sample at the lower part of the tuyere than before, and for this purpose, it is preferable to provide openings at the upper part and lower part of the tuyere, or to separately form openings vertically.

[0012] Here, tracer coke is a coke having similar reactivity of carburizing to ordinary coke and molten iron or a similar material thereof, and can be distinguished from ordinary coke by its physical and chemical properties. What is it? That is, it is considered that the furnace core coke is itself consumed by the carburization of the molten iron, thereby renewing the furnace core. Specific examples include pitch coke, molded coke, high-temperature carbonized coke, and the like. Since the pitch coke has a higher carbon content per weight and a lower ash content than ordinary coke, the remaining amount can be easily measured by chemical analysis of the collected coke. In the case of molded coke, since the reactivity is high, the residual amount can be easily measured by conducting a reactivity test of the collected coke. In addition, since the shape of the coke is different from that of ordinary coke, the remaining amount can be measured by performing a separation treatment, and the degree of consumption of the coke itself due to carburization can be determined. In the case of high-temperature carbonized coke, the history temperature is higher than that of ordinary coke, so that the history temperature can be estimated based on the degree of graphitization and the residual ratio can be measured. These pitch coke, molded coke, high-temperature carbonized coke, etc. may be used by mixing them with ordinary coke at a fixed ratio without charging them in their entirety.

The tracer coke described above is consumed by its own carburizing reaction by measuring its residual rate.
You will see the result of the movement of the position due to the consumption of the entire coke below it in the furnace, but mix in the coke that does not react at all in the furnace as a tracer,
Finding out how its position changes can serve a similar purpose. In this method, a certain percentage of refractory granules such as zirconia balls and alumina balls are mixed with ordinary coke, and the mixture is inserted as tracer coke. Next time, for example, when sampling is performed at the same position with a pipe of the same thickness, if the amount of zirconia balls or the like of the tracer is reduced, it means that coke at a position lower than that is reduced and the overall level is reduced. As mentioned earlier, more accurate information can be obtained by examining how much zirconia balls and the like when inserted through the upper opening and later inserted into the lower opening are sampled at the lower opening as described above. can get.

The refractory granules can be mixed not only with ordinary coke but also with the above-mentioned pitch coke, molded coke, high-temperature carbonized coke and the like to obtain information on changes in their positions. As a result, it is possible to obtain information that separates whether the measured value of the residual ratio of the coke is due to the consumption of the coke itself or to the decrease in the level due to the decrease of the coke at a position below the coke itself. In other words, if the proportion of refractory particulates decreases when sampled, it means that the level of the entire coke has decreased, and if the proportion has increased in a certain part, it means that the coke in that part has been consumed. It is.

In carrying out the method of the present invention, the tip portion of the double tube may be simply a double tube. However, it is possible to prevent coke from being clogged in the tube when inserted into the furnace core, and It is advisable to change the shape of the tip to take in the coke inside. FIG. 4 shows this example, in which the tip is only the outer tube 3 and the tip of the inner tube 2 is at a position retracted from this. The tip 3C of the outer tube 3 has an inner diameter smaller than the inner diameter of the other portion at the same time as the inner tube 2.
Is even smaller than the inner diameter. As a result, when the double tube is inserted into the furnace, the core coke entering the tube is not compressed because the inner diameter of the inner tube is larger than the inner diameter of the distal end portion 3C of the outer tube. You can enter smoothly.

FIG. 5 shows another example. The inner diameter of the distal end portion 2C of the inner tube 2 is smaller than that of the other portion, so that the same effect as in the previous example can be obtained. In this example, the distal end portion 3C of the outer tube 3 is tapered so as to reduce the insertion resistance. In any of the above cases, the length of the portion where the inner diameter of the distal end portion of the double pipe is reduced should be equal to or less than the inner diameter of the other portion, and if it is too long, the effect is reduced. Also, the degree of reducing the inner diameter may be reduced by about 5% to 15% of the inner diameter of the other parts. Also, the sampler pipe for sampling the tracer coke charged in the furnace can be smoothly sampled into the pipe if the inside diameter of the tip is smaller than the other parts, as in the case of the double pipe described above. preferable.

[0017]

【Example】

Example 1 A method for detecting the renewal of a blast furnace core according to the present invention employs an internal volume of 3880 m.
^This was performed in the blast furnace of No. ³ . After cooling, a double pipe made of a non-water-cooled steel pipe having an outer diameter of 215 mm and an inner diameter of 180 mm was placed 5 m from the tuyere and 5 m from the furnace wall in the blast furnace by the method shown in FIG. Inserted until the tip comes. After extracting the inner tube, another inner tube having an inner diameter of 165 mm and filled with only formed coke up to a position 4 m from the tip was inserted into the outer tube and left in the furnace by the method shown in FIG.

Ten days later, when the wind was stopped again, a tube having an inner diameter of 165 mm at the tip from the same tuyere was inserted and sampled. Then, the formed coke and the ordinary coke were separated according to their shapes. As a result, in the sample at the tip portion near the center of the furnace core, the proportion of formed coke was reduced to 55%, and the weight of each formed coke was also reduced by an average of 23%. In the sample 2.5 m from the tip, the proportion of formed coke was reduced to 20%, and the weight of each formed coke was also reduced by 43% on average.

According to these results, the weight loss of the individual formed coke is due to the consumption of the formed coke in the place, and the decrease in the proportion of the formed coke is caused by the consumption of the formed coke in the place and the consumption of the coke below. It can be determined that both are caused by the decrease in the overall level. It can also be seen that the renewal speed of the coke in the peripheral part is higher than that in the central part of the core.

Example 2 After the wind has stopped, the outer diameter of the outer tube is 215 m by the method shown in FIG.
m, a double pipe made of a non-water-cooled steel pipe having an inner diameter of 180 mm was inserted from the tuyere to a position 5 m from the furnace wall in the blast furnace, and the inner pipe was extracted. A tracer coke containing 5% by weight of zirconia balls having a diameter of 20 mm mixed with ordinary coke is used. This is filled into an inner tube having an inner diameter of 165 mm, which is different from the previous one, to a position 4 m from the tip, and inserted into the outer tube. , In the furnace according to the method shown in FIG.

Seven days later, when the wind was stopped again, a sample having an inner diameter of 165 mm at the tip from the same tuyere was inserted and sampled. As a result, the ratio of zirconia balls in all the samples at the tip was reduced to 1/3 of the initial value, but when the portion where zirconia balls were not mixed was excluded, the ratio was 8%.
% Had increased. In addition, the proportion of zirconia balls in all samples at a position 2.5 m from the tip was reduced to 1/4 of the original, but excluding the portion where zirconia balls were not mixed, the proportion increased to about 10%. Was.

These results show that the coke weight per unit weight of the zirconia ball is reduced from 95/5 to 92/8 at the center and 90/10 at the periphery. Therefore, it is estimated that about 39% of the coke in the center part of the furnace core was consumed and about 53% of the coke in the peripheral part was consumed. Further, the situation of a decrease in the overall level due to the consumption of coke below the charged tracer coke can also be determined for each of the central portion and the peripheral portion from the remaining ratio of zirconia balls in all the samples.

[0023]

According to the method for detecting the renewal of the blast furnace core of the present invention, it is possible to directly grasp the renewal state of the core coke, which has been difficult in the past. As a result, reliable data can be obtained as an index of the in-furnace activity for determining the blast furnace operation policy, which greatly contributes to the efficiency and stability of the operation.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lower part of a blast furnace showing a method of the present invention.

FIG. 2 is a sectional view of a lower part of a blast furnace showing a method of the present invention.

FIG. 3 is a sectional view showing a configuration of a double pipe used in the method of the present invention.

FIG. 4 is a sectional view showing a configuration of a double pipe used in the method of the present invention.

FIG. 5 is a sectional view showing a configuration of a double pipe used in the method of the present invention.

[Explanation of symbols]

 1 double pipe 2 inner pipe 3 outer pipe 4 tuyere

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisao Kamiyama 5-3 Tokai-cho, Tokai-shi, Aichi Prefecture Nippon Steel Corporation Nagoya Works (58) Field surveyed (Int. Cl. ⁶ , DB name) C21B 7/24 305 C21B 5/00 310

Claims (6)

(57) [Claims] 1. After inserting a double pipe consisting of an outer pipe and an inner pipe having an open end into the core of a blast furnace when the blast furnace is shut off, only the inner pipe is extracted and a tracer coke is separately charged. A pipe is inserted into the outer pipe, the outside of the furnace inside the inner pipe charged with the tracer coke is pressed by a stopper, and the inner pipe and the outer pipe are pulled out to leave only the tracer coke in the furnace. A method of detecting the renewal of a blast furnace core, wherein the status of the tracer coke is investigated by sampling. 2. The method for detecting renewal of a blast furnace core according to claim 1, wherein pitch coke is used alone or as a mixture of ordinary coke as a tracer coke. 3. The method for detecting renewal of a blast furnace core according to claim 1, wherein the molded coke is used alone or as a mixture of ordinary coke as the tracer coke. 4. A method for detecting renewal of a blast furnace core according to claim 1, wherein high-temperature carbonized coke is used alone or as a mixture of ordinary coke as the tracer coke. 5. The method for detecting renewal of a blast furnace core according to claim 1, wherein refractory granules mixed with coke are used as the tracer coke. 6. The blast furnace core renewal according to claim 1, wherein when the double tube or the sampler is inserted into the blast furnace, the inside diameter of the tip portion is smaller than the inside diameter of the other portions. Detection method.