JP4353880B2 - Converter operation method - Google Patents

Description

  The present invention relates to a method of operating a converter when efficiently using a plurality of converters.

As is well known, in the converter process, hot metal is charged into the converter, dephosphorization and decarburization are performed by adding auxiliary materials and blowing oxygen, and the phosphorus concentration and carbon concentration reach predetermined values. Is producing molten steel.
FIG. 11 shows a conventional converter facility, which includes a converter, a ladle that supplies hot metal to the converter, and a crane that conveys the ladle. There were three converters in total, two of them were in operation, and the remaining one was in a dormant state.
In detail, since the hot metal is charged into the converter, the inner wall is always exposed to high temperature, and the refractory bricks constituting the inner wall are gradually melted. That is, the converter has a furnace body life in which the refractory bricks melt and lose the function of the converter itself. It is impossible to operate the converter over a long period of time beyond this life, and after the converter has been operating for a certain period of time, a large-scale repair, such as replacing the refractory bricks in the converter, Is to be performed. The one converter that was out of service was in such a furnace repair operation and in the subsequent stop state.

  FIG. 12 shows an operation schedule in the converter equipment of FIG. 11, and FIG. 12 (a) shows converter operation periods (that is, converter life) for three converters A, B, and C. And the schedule of furnace repairs are shown. According to this schedule, the two converters within the converter life were refined with hot metal, and the remaining one converter was repaired and closed. Assuming that converter A and converter B are in operation as indicated by P in the figure, it is assumed that it is time to replace the refractory bricks attached to the inner wall of converter A. In such a case, the converter A enters the furnace repair work, and instead, the converter C that has been closed until now is put into operation. Then, even if the furnace repair of the converter A was completed, the converter A was considered as a backup, and was not in operation, but was in a closed state. In other words, if one of the two converters B, C used is out of order or needs to be repaired, the converters B, C are stopped and are currently closed. The converter A was restarted.

  FIG. 12 (b) shows the charge status at each converter B, C when two converters B, C are operating. Converter charge refers to a series of processes in which molten iron is charged into the converter, blown into the molten iron, and the produced molten steel is discharged. The time from the end to the end is called steelmaking time. Usually, about 5000 charges are performed within one converter life. As shown in the figure, if necessary, there is a converter downtime between each charge, and this time is a simple repair that greatly improves the furnace life by spraying fireproof repair material on the inner wall of the converter. It is time to perform “repair”.

If the converter life is converted to days, it is roughly around 150 days, and the furnace repair is around 20 days. On the other hand, one charge in the converter is about 35 minutes, and repair of the converter has 10 minutes to several hours. In view of this, FIG. 12 is summarized as follows. FIG. 12 (a) shows the converter process divided into a furnace repair period and an operation period as seen macroscopically on a daily basis. Yes, FIG. 12 (b) shows the converter process divided into charge and repair period when viewed in a microscopic (microscopic) manner in time units.
As can be seen from the above, in conventional conventional converter facilities, only two converters are always in operation from the macro and micro perspectives, and the remaining one is closed as a backup. It is normal to be.

In such a converter facility, the techniques of Patent Document 1 and Patent Document 2 have already been disclosed for efficiently operating two converters.
In the technique of Patent Document 1, the molten metal dephosphorized and refined in one converter is received in a receiving hot pot, and the hot pot is transported to the other one through the work floor opening, where decarburization refining is performed. In addition to reducing the slag removal time in dephosphorization refining and reducing the dephosphorization refining time and decarburization refining time to the same extent, the play time of the decarburization refining furnace is eliminated as a whole. It improves the steelmaking efficiency. In other words, it is a technique for increasing the steelmaking efficiency by making the charge time in one converter the same as the charge time in another converter.

In the technology of Patent Document 2, the operation of opening the flue damper of the converter that starts blowing and the operation of closing the damper of the flue of the converter that has finished blowing are performed in one stage in two converters. The damper operation is performed simultaneously and in parallel to shorten the wind stop time at the time of switching, and relates to a method for operating the damper of the flue at the time of charge switching of the converter.
Japanese Patent No. 3486886 JP-A-6-65653

  In the converter equipment mentioned above, when thinking about increasing the production capacity of molten steel, not only two converters will be operated, but also another converter that is in a closed state will be operated. It is recommended that the converter be in operation at the same time (3/3 unit operation). However, when all three converters are put into operation, the converter loses the opportunity for repairing the furnace, resulting in inconvenience that the operation cannot be continued for a long time. Therefore, in order to carry out the furnace repair, it becomes necessary to set a 2/3 unit operation in which one converter is stopped and only the other two units are operated, for some percent of the total operation time. In other words, it is a very important matter to set an appropriate ratio between the period of 3/3 operation and the period of 2/3 operation.

However, in the operation of the converter, a technique for obtaining an optimum ratio between the period of 3/3 operation of the converter and the period of 2/3 operation has not been established yet. Even if attention is paid to Patent Document 1 and Patent Document 2 described above, these technologies are intended to improve efficiency in the operation of two converters while taking a microscopic view of the converter process. It is difficult to do.
Therefore, in view of the above problems, the present invention is a converter facility having a converter peripheral facility that has only the ability to blow down two converters, and the operation schedule of the simultaneous operation status of the three converters is used. The object is to provide a converter operating method that can be incorporated.

In order to achieve the above object, the present invention takes the following technical means.
That is, the technical means for solving the problems in the present invention is a converter facility equipped with three converters (A, B, C) that performs hot metal blowing, for converters that have exceeded the lifetime of the furnace body. The repair is “ furnace repair” and the repair of the inner wall of the converter is “repair”, and all three converters are in operation for 3/3 during the repair period or not in operation. The period during which at least one of the converters is operating is defined as the total operating period, and the ratio of the 3/3 operating period to the total operating period is defined as the 3/3 unit ratio. The three converters (A, B, C) are operated so that the ratio of the three units is 0.5 to 0.95, and the operation order of the converters that has been followed by “A → B → C” is “ In the reverse order of “C → B → A”, the converter A has a time for repairing and repairs .

Inventor of the present application, in the operation of the converter, the ratio of the 3/3 unit operation period and the total operation period (2/3 unit operation period + 3/3 unit operation period) of the converter will be the molten steel productivity. Is clarified logically based on the simulation described below.

[Conditions for simulation]
In the simulation, the following conditions were assumed.

-The repair probability A, which is the number of repairs per charge, was used as a simulation parameter, and the amount of repair per repair was fixed.

  -As shown in FIG. 2, the repair effect C is large when the repair probability A is small, but becomes smaller as the repair probability A increases. In other words, it is said that at the beginning, it is effective to extend the converter process for 4 charges by one repair, but after that, the effect is increased every time the repair frequency B (reciprocal of repair probability A) increases by 0.1. Decrease by 10%. This means that if there are many locally damaged parts (locally damaged parts) of the refractory in the furnace, the repair effect will be great even with a low repair frequency, but if repairs are carried out frequently and the locally damaged parts are reduced, repairs will be made. This reflects a decrease in effect.

・ The life D of the converter when no repairs were made was 2500 charges.
・ The molten steel productivity (number of charges) at the time of 3/3 base operation is 80, and at the time of 3/3 base operation, the productivity decreases by 0.07 for every repair.
-The molten steel productivity (number of charges) at the time of 2/3 base operation was set to 68, and repair was not performed at the time of 2/3 base operation.
・ The number of days for furnace repair was fixed at 14 days.

[Simulation formula]
The variables and relational expressions used in the simulation are as follows.

A: Repair probability → Number of repairs per charge (times / ch).
-B: Repair frequency → Value indicating how many charges are repaired. It is the reciprocal of A.
-C: Repair effect → This means how much charge is required to extend the life of the converter in one repair. The relationship is shown in FIG.

・ D: Converter life (ch)
D (n + 1) = D (n)
+ D (n) × (A (n + 1) −A (n)) × C (2)

When a repair is performed on a converter that has a certain repair probability, the converter effect is as follows: converter life x increase in repair probability x repair effect = D (n) x (A (n + 1) -A ( n)) × C, and this is added to the current converter life D (n) to obtain the converter life D (n + 1) after repair. Here, when repair probability = 0, n = 1, n = 2 when repair probability = 0.1, and n = 3 when repair probability = 0.2. The repair probability was calculated between 0 and 1.0 as 0.1.

・ E: Converter operation days
E = D × (F × 3 + (1−F) × 2) / I (3)
The converter operating days E are calculated by dividing the converter life D by the average daily charge I / (F × 3 + (1−F) × 2) per converter. F is a 3/3 group ratio described below.

-F: 3/3 group ratio In this invention, the 3/3 group ratio of a converter is calculated | required by following Formula.

3/3 group ratio F = 1-CH × R / L (1)

CH: Total number of charges per day in converter facilities (ch / day)
R: Number of days (days) that the converter is under repair or outage
L: Furnace life of the converter (ch)

The derivation process of Equation (1) is as follows. That is, the converter is operated continuously throughout the year 365 days, and the operation day (period) of such 365 days is basically 3/3 operation. However, since one converter is shut down during the period during which the furnace is being repaired, the operation is 2/3. Than those things
3/3 unit ratio = (3/3 unit operation period) / total operation period
= (Total operating period-2/3 base operating period) / Total operating period
= (365 days-the number of days during which the furnace is repaired) / 365 days. By transforming this formula sequentially,
3/3 base ratio = 1-Furnace repair times x R / 365
Here, R is the number of days required for one furnace repair (including converter shutdown).

Since the number of times of furnace repair R = number of charges per day CH (ch / day) × 365 days / converter life L (ch),
3/3 group ratio = 1-CH × R / L (1)
It becomes.

・ G: Number of production charges at 3/3 base
G = 80−A × μ × 80 / F (4)
Here, μ is a production influence coefficient, adopting 0.07 or 0.15, and means the number of charges reduced by performing repair once. Therefore, A × μ × 80 / F means productivity (the number of charges) that is actually reduced by repair.

・ H: Number of production charges at 2/3 base → Fixed value at 68ch / day.

・ I: Total number of charges per day (total number of production charges)
I = G × F + H × (1−F) (5)

・ J: Total number of charges per day when repairs are not taken into account J = 80 × F + H × (1-F) (6)
This equation can be derived by setting G = 80 in equation (5).

・ K: Reduced productivity due to repair K = JI (7)
By subtracting I from the above-mentioned J, K can be obtained.

[simulation result]
The results of simulation of molten steel productivity using the above relational expressions (2) to (7) with the repair probability A as a parameter are shown in FIGS. FIG. 3 shows the calculation results in the form of a table, and FIGS. 4 to 7 are graphs based on the calculation results.
FIG. 4 shows the repair probability A on the horizontal axis and the converter life D on the vertical axis. From this figure, when the repair probability A is 0, that is, when no repair is performed, the life of the converter is 2500 charges of the initial value, and as the repair probability A increases, the converter life D increases to about 20000 ch. I understand that. It has been clarified that many repairs can increase the life of the converter.
FIG. 5 shows the relationship between the 3/3 base ratio F and the total production charge number J without considering repairs. As can be seen from this figure, the total production charge number J increases linearly as the 3/3 base ratio F increases, and when the 3/3 base ratio F is 0%, J = 68. When F = about 100%, J = 80, which is a significant increase.

On the other hand, FIG. 6 shows the relationship between the 3/3 base ratio F and the productivity reduction K due to repair. From this figure, it can be determined that when the 3/3 group ratio F is up to 55%, the decrease K in productivity due to repair is 0, but when it exceeds this, the decrease K is remarkably increased.
To summarize the above results:
(i) By increasing the 3/3 unit ratio F, the three converters will be close to continuous operation, and the productivity of molten steel will increase (Fig. 5).
(ii) By increasing the 3/3 unit ratio F, the three converters will be in full operation, and the opportunity to repair the converter will be reduced. Of course, in order to cover it and extend the life of the furnace, many repairs of the converter are performed (FIG. 4).

(iii) However, although repair is an operation to stop the converter although it takes 30 minutes to several hours, the productivity will be reduced under the situation of (ii), that is, the situation where the number of repairs is large (one time Repair 0.07ch). Therefore, by increasing the 3/3 base ratio F, the molten steel productivity decreases with the repair amount (FIG. 6).
FIG. 7 is a trend of (i) and (iii), in other words, adding FIG. 5 and FIG. 6 respectively, and the horizontal axis indicates the 3/3 base ratio F and the vertical axis indicates the total production charge number I. It is shown. The graph in the figure is convex upward as the 3/3 group ratio F increases, and when the 3/3 group ratio F is about 80%, the total production charge number I is about 76, which is the highest value. It has become.

Considering this result, in the present invention, the maximum value of the total production charge number I is reduced by about 2-3%, that is, I = 74 is considered as an allowable value, and the 3/3 base ratio F is 50% to 95%. Three converters will be operated so that
The technical means for solving the problems in the present invention includes two converters when repairing the converter peripheral equipment provided in the converter equipment and having a function necessary for operating the converter. 2/3 units are defined as the situation in which is operating and the other unit is in furnace repair or outage. If the repair time for the converter peripheral equipment is 3 hours or more, 2/3 units are in operation. In the case of 3 hours or less, 3/3 units are operated in which all three converters are operated.

In converter operation, failure of peripheral equipment such as the lance cannot be inserted from the loading port may occur. In such a case, the repair may take a short time (about 30 minutes) or may take a relatively long time (for example, 5 hours or more).
The inventor of the present application has examined a number of failure examples of the converter peripheral equipment, and if the repair time of the converter peripheral equipment is short, the charge order is changed to 3/3 operation. It has been found that it is very advantageous from the viewpoint of molten steel productivity if the downtime of the converter is secured by devising it and this downtime is used as repair time for the equipment around the converter.

On the other hand, if repair time for converter peripheral equipment takes more than 5 hours, stop the converter corresponding to the repair and put the two converters in operation (2/3 units) in the same way as when repairing the furnace. It is also clear that it is advantageous from the viewpoint of molten steel productivity.
By operating the three converters in this manner, the converter can be operated without reducing the molten steel productivity as much as possible.
As technical means for solving the problems in the present invention, when performing “repair” which is simple repair to the inner wall of the converter, the time required for repair is within a range of T / 4 to 3T (T Is steelmaking time). The reason will be described below.

FIG. 10 shows the result of simulating the degree of extension of the converter life (repair effect) and the time required for collecting the metal when the repair time changes from about 5 to 600 minutes. In all calculations, the steelmaking time is 35 minutes and the hot metal supply time at the crane is 15 minutes.
The horizontal axis in the figure is the repair time converted in terms of the steelmaking time T, and the vertical axis shows the repair effect and the bullion collecting time.
Graph I in the figure shows the change in the repair effect. By making the repair time longer, the repair work can be performed reliably, and the number of charges extending in one repair increases. Has been. Increasing the repair time to about 0.25 T (T / 4) extends the converter life by about 3 charges. On the other hand, if the repair time is about 0.4 T or more, the repair effect = 5.0 charge will not increase any more.

Graph II shows the change in the time required for collecting bullion. When the repair time is 3T or less, the bullion collecting time is zero, and when the repair time is 3T or more, the bullion collecting time is generated. This reflects that the longer the repair time, the lower the temperature of the converter itself, and the greater the possibility that metal will adhere to the converter inlet. Therefore, it is not a good idea to make the repair time extremely long. As can be seen from the graph II, if the repair time is set to 3T or less, the work time for the bullion collecting operation can be reduced.
In view of these matters, by setting the repair time within the range of T / 4 to 3T, it is possible to prevent an increase in the time for the bullion collecting operation while making the repair effect appropriate.

  According to the present invention, in operation in a converter facility having three converters, the molten steel production capacity can be reduced by appropriately allocating the period for operating the three converters and the operation period for the two converters. Can be greatly improved.

Hereinafter, an embodiment of a hot metal supply method to a converter according to the present invention will be described with reference to the drawings.
The converter equipment 1 of this embodiment is substantially the same as the conventional example shown in FIG. 11, and includes three converters 2, a ladle 3 that supplies hot metal to these converters 2, and this ladle 3. It has two cranes 4 to convey. Further, each of the three converters 2 is provided with an exhaust gas treatment facility 5 that collects exhaust gas generated by blowing and removes harmful substances or collects carbon monoxide. An oxygen supply facility 6 for supplying oxygen to the converter 2 is provided. The oxygen supply equipment 6 can supply twice the amount of oxygen used by one converter for blowing, and the exhaust gas treatment equipment 5 can supply CO gas discharged from the two converters 1. Has the ability to collect. That is, the converter peripheral equipment 7 composed of the exhaust gas treatment equipment 5 and the oxygen supply equipment 6 has the ability to simultaneously perform blowing in the two converters 2, and the three converters 2 Simultaneous blowing in is impossible.

As shown in FIGS. 1 to 7, the present invention is a converter facility 1 having three converters 2 that perform hot metal blowing, and is a repair to the converter 2 that has passed the furnace body life. ”Is defined and a period in which the number of converters 2 that are in operation is three is defined as a 3/3 unit operation period, and at least one of the converters 2 is in operation. The ratio of the 3/3 unit operation period is determined as a 3/3 unit ratio, and the three converters 2 are operated so that the 3/3 unit ratio is 50% to 95%.
Explaining each process in the converter equipment 1 in detail, first, the hot metal in the ladle 3 is conveyed by the crane 4 and charged into the converter 2. Specifically, the converter 2 is tilted, and scraps and the like are charged into the furnace, and then molten iron is poured.

Thereafter, in order to remove mainly phosphorus P in the hot metal and make carbon C suitable, a lance (not shown) is inserted from the furnace port of the converter 2 and is brought close to the upper surface of the hot metal, and oxygen gas is blown. At the same time, refining (blowing) is started while the hot metal is stirred from the furnace bottom. At the same time, the coolant such as the slag forming and iron oxide Fe _x O _y, such as lime CaO, i.e. by turning on the auxiliary materials, phosphorus P is shifted to the slag phase to react with the entered oxygen, above the hot metal Laminate in a floating state.
Thus, the molten iron is charged into the converter 2 and the molten steel is blown and the molten steel is adjusted in composition, and a series of processes in which the molten steel is discharged from the converter 2 is referred to as “charging”. One charge takes about 35 minutes.

  On the other hand, the inner wall of the converter 2 is always exposed to a high temperature by the hot metal, and the refractory bricks constituting the inner wall are gradually melted down. Therefore, the converter 2 has a “lifetime” in which the refractory bricks melt and lose the function of the converter itself. Since it is impossible to operate the converter 2 over a long period beyond this lifetime, the converter 2 is operated for a certain period of time as shown in FIG. Large-scale repairs, such as replacing refractory bricks, "furnace repairs" are being carried out. When the life of the converter 2 is converted to days, it is roughly 150 days, but the furnace repair is about 20 days. Moreover, it is normal that about 5000 charge is performed within one converter lifetime.

In addition, in normal converter operation, repair work such as metal removal, hole winding, and refractory repair for the converter 2 is performed as needed. These operations are essential for stable operation of the converter 2. It is.
The bullion removing operation referred to here is an operation of removing the bullion because the molten iron is fixed to the vicinity of the molten metal inlet of the converter 2 by slapping or the like. This is performed about once every 10 charges and has a time of about 30 minutes.
The hole winding operation is an operation of replacing the refractory bricks at predetermined intervals because the refractory bricks at the outlet of the converter 2 are gradually deteriorated by the molten steel. The hole winding operation is performed once for about 100 charges, and requires an operation time of about 60 minutes.

Repair of refractory bricks (refractories) is a simple repair that greatly improves the life of the furnace by spraying fireproof repair material on the inner wall of the converter 2, and is performed once every 10 charges. Repair takes about 30 minutes.
FIG. 1 (a) describes the operating status of the three converters 2 from a macro viewpoint where, for example, one day is the minimum unit, and FIG. It is described in terms of
First, as indicated by P in FIG. 1A, it is assumed that the converter A and the converter B are in operation, and the converter C is undergoing furnace repair and subsequent suspension. . Thereafter, the converter C is also in an operating state so that the hot metal is blown. In this state, the three converters 2 are operating at the same time, and the operation period is 3/3.

After that, the furnace life of the converter A comes, and it becomes necessary to repair the converter A. Furnace repair is to lower the temperature of the converter 2 to room temperature, remove the refractory refractory bricks, and paste new refractory bricks loaded from the inlet of the converter 2 inside the furnace. The period of furnace repair takes from several days to 20 days. While the furnace is being repaired, two furnaces B and B are blown, and this situation is defined as the 2/3 operation period.
During the 3/3 unit operation period, as shown in FIG. 1B, the three converters 2 are sequentially operated, and the charges are not completely overlapped in parallel. Although details will be described later, the converter peripheral equipment 7 does not have the capacity to operate the three converters 2 at the same time. By operating the converter 2 sequentially, three converters 2 are operating in a macro manner, but two converters 2 are operating microscopically and charging is performed sequentially. Productivity can be greatly improved.

However, when all the three converters 2 are put into operation in order to increase the molten steel production capacity, the converter 2 loses the opportunity for repairing the furnace, resulting in a disadvantage that the operation cannot be continued for a long time. Come. Therefore, in order to carry out the furnace repair, it becomes necessary to set 2/3 units operation in which only one converter 2 is stopped and only the other two units are operated, with a certain percentage of the total operation time. . In other words, it is a very important matter to set an appropriate ratio between the period of 3/3 operation and the period of 2/3 operation.
In this embodiment, the 3/3 base ratio, which is the ratio of the 3/3 base operating period to the period in which at least one of the converters 2 is operating, is obtained using the formula (1) The 3/3 group ratio is set to 50% to 95%.

As can be seen from FIG. 7, by setting the 3/3 base ratio to 50% to 95%, the total production charge number I can be suppressed to about 2-3% reduction of the maximum value, and the total production charge number I can be reduced. Always above 74. By doing so, it is possible to maintain a high molten steel productivity and to ensure that the converter is repaired and to have a long life.
Next, the charging order of each converter 2 during the 3/3 base operation period of the converter 2 will be described.
FIG. 8 shows the order of charging in the three converters 2 in this embodiment. This figure is a detailed view of FIG. 1 (b), which shows a microscopic view of the operation status of the converter 2, and shows the order of charge in the three converters 2 in this embodiment. .

First, before the end of blowing in the first converter 2 (converter A), the second converter 2 (converter B) is set to start blowing, and the third converter Blowing start of the furnace 2 (converter C) is performed before the end of blowing in the second converter 2 and between the end of the previous blowing in the first converter 2 and the start of the next blowing. It is set.
Specifically, in the converter A, the hot metal charging is started before the time 0 min, and the blowing is started around the time 0 min. Blowing ends after 20 minutes, and then the molten steel is dispensed, and the steel output is completed after 30 minutes.

In the converter B, the hot metal charging is started before the time 10 minutes, and the blowing is started around the time 10 minutes. Blowing ends after 30 minutes, and then the molten steel is dispensed, and the steel output is completed after 40 minutes. As can be seen from the figure, the start of the blowing in the converter B is in the middle of the blowing of the converter A, and during the time of 10 min to 20 min, the blowing is performed in both the converters A and B. ing.
In the converter C, the hot metal charging is started before 20 minutes, and blowing is started around 25 minutes. Blowing ends after 45 minutes, and then the molten steel is dispensed, and the steel output is completed after 55 minutes. The start of blowing in the converter C is during the blowing of the converter B and after the end of the blowing in the converter A. That is, the order in which blowing is performed is A0->B0-> C0, and is lined up on the diagonally downward arrow in the figure.

Further, before the blowing in the converter C is completed, the hot metal charging into the converter A is started again, and the blowing is performed subsequently. Similarly, in the middle of blowing in the converter A, the blowing in the converter B is started. In the middle of the blowing of the converter B and after the completion of the blowing of the converter A, the blowing in the converter C is performed. Alchemy is to be started. That is, the order in which blowing is performed is A1 → B1 → C1, and is arranged on an arrow that is slanted to the right in the figure.
By doing in this way, in any phase (time), there are two converters 2 during blowing, which does not exceed the capacity of the converter peripheral equipment 7. However, when viewed macroscopically, as shown in FIG. 1A, it is a 3/3 unit operation period in which three units are operating at the same time, and the hot metal production capacity can be significantly improved. In FIG. 8, since the start of 3 times of blowing is included in about 35 minutes, the converter equipment 1 in the operational state has a production capacity of 3 charges in 35 minutes, that is, 5 charges in 1 hour. Will have.

If attention is paid to the charge including the blowing A0 in FIG. 8, the start of the blowing of the converter B and the converter C between the start of the blowing A0 and the start of the blowing A1 in the next charge. It can be seen that there is one start of blowing each. A charge under such circumstances is defined as a charge in a “sequentially operating converter”. In addition, the number of charges of the converters 2 that are operating sequentially with respect to the total number of charges of the three converters 2 is defined as a “sequential operation ratio”.
As this sequential operation ratio increases, the three converters 2 are operating without waiting time, and theoretically the molten steel production capacity is improved.

However, in reality, the time (period) for the above-mentioned “repair of the converter” is necessarily required, and when the sequential operation ratio of the converter 2 is large, it becomes difficult to secure these repair times, Molten steel productivity falls.
In the case of the present embodiment, the sequential operation ratio of the three converters 2 is between 40% and 95%. More preferably, it is in the range of 50% to 90%, and the maximum value of productivity can be obtained by sequentially setting the operation ratio to 75%.
Moreover, in this embodiment, in order to obtain such repair time reliably, as shown in FIG. 9, by changing the operation order of the converter 2 that has continued from A → B → C from C → B → A, The converter A has time for repairs. That is, after operating the converter C, the converter B is operated, and then the converter A is operated, so that a time close to one charge in the converter A can be set in a non-operating state, and the period is set as a repair time. I am doing so.

In addition, as shown in FIG. 10, the repair time described above is within a range of T / 4 to 3T, so that it is possible to prevent an increase in the time for the metal collecting operation while making the repair effect appropriate. It becomes like this. More preferably, the repair time is set to T / 4 to 1.5T.
Further, in the operation of the converter 2, there may be a failure of the converter peripheral equipment 7 such that the lance cannot be inserted from the loading port. In such a case, the repair may take a short time (about 30 minutes) or may take a relatively long time (for example, 5 hours or more).
Therefore, when the repair time of the converter peripheral equipment 7 is short, the repair time is reduced by, for example, reversing the charge order as described in the present embodiment after the 3/3 operation. If it is ensured and this repair time is used as the repair time of the converter peripheral equipment 7, it is very advantageous from the viewpoint of molten steel productivity.

On the other hand, when the repair time of the converter peripheral equipment 7 takes 5 hours or more, rather than securing the repair time in the reverse order or the like, the converter 2 corresponding to the repair is suspended and the same as in the repair of the furnace. It is advantageous from the viewpoint of molten steel productivity when the two converters 2 are in an operating state (2/3 operation). In order to secure the repair time for the converter peripheral equipment 7, the boundary of whether the converter 2 is operated by 3/3 or 2/3 is necessary for the temperature rise when the converter 2 is restarted. Preferably, about 3 hours are adopted, and “repair time = 3 hours” is set as the boundary value.
In addition, the hot metal supply method to the converter 2 of this invention is not limited to the said embodiment. Further, the converter 2 may be any one of a top blowing converter, a bottom blowing converter, and an upper bottom blowing converter.

The order of the converter operation concerning this invention is shown, (a) was seen macroscopically, (b) was seen microscopically. It is the figure which showed the relationship between repair probability and repair effect. This is a simulation result of molten steel productivity with repair probability as a parameter. It is the figure which showed the relationship between repair probability and converter life. It is the figure which showed the relationship between 3/3 group ratio and molten steel productivity. It is the figure which showed the relationship between 3/3 group ratio and the reduction | decrease amount of the molten steel productivity by repair. It is the figure which showed the relationship between 3/3 group ratio and total molten steel productivity. It is the figure which showed the order of the charge of a converter. It is the figure which showed the order of the charge of a converter (in the case of reverse order). It is the figure which showed the relationship between repair time, repair effect, and bullion taking time. It is the front schematic of the converter equipment concerning the past and this invention. The order of the conventional converter operation is shown, (a) is a macro view, and (b) is a micro view.

Explanation of symbols

1 Converter 2 Converter 7 Converter peripheral equipment

Claims (4)

In the converter equipment equipped with three converters (A, B, C) that perform hot metal blowing, repair of the converter that has exceeded the lifetime of the furnace body is referred to as “furnace repair” and the inner wall of the converter “Repair” is the repair period, and the period in which all three converters are operating rather than being repaired or not operating is defined as the 3/3 operation period, and at least one of the converters is operating The period is defined as the total operating period, and the ratio of the 3/3 operating period to the total operating period is defined as the 3/3 base ratio.
Operate the three converters (A, B, C) so that the ratio of 3/3 units is 0.5 to 0.95, and operate the converter that has been followed by “A → B → C”. A method for operating a converter, characterized in that the order of repair is made in the reverse order of “C → B → A”, and repair is performed by making time for repairing the converter A. The method for operating a converter according to claim 1, wherein the 3/3 group ratio is obtained by the following equation.

3/3 group ratio = 1-CH x R / L (1)

CH: Total number of charges per day in converter facilities (ch / day)
R: Number of days (days) that the converter is under repair or outage
L: Furnace life of the converter (ch) When carrying out repair of converter peripheral equipment that is provided in the converter equipment and has a function necessary for operating the converter,
When two converters are in operation and the other one is in furnace repair or outage, and defined as 2/3 unit operation, and the repair time of the converter peripheral equipment is 3 hours or more The operation method of a converter according to claim 1 or 2, wherein 2/3 units are operated and 3/3 units are operated in which all three converters are operated within 3 hours . The converter operation method according to any one of claims 1 to 3, wherein the time required for the repair is set within a range of T / 4 to 3T (T is a time for steelmaking).

Images