JP3933109B2 - Operation method of steelmaking furnace - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a method for operating a steelmaking furnace, and more specifically, it is possible to reduce the brand and amount of scrap by simplifying and facilitating the logistics of scrap used in a steelmaking furnace such as a converter or an electric furnace. The present invention relates to a method of operating a steelmaking furnace that can be optimally blended according to standards.

  For example, steelmaking furnaces such as converters and electric furnaces make molten steel from scrap. After refining this molten steel so as to meet the product standards, in some cases, it is supplied to another refining furnace, and then the molten steel is systematically supplied to a semi-finished product manufacturing process such as a continuous casting machine.

  In that case, the scrap used as a raw material is constituted by scrap generated from a manufacturing facility such as a continuous casting machine or a rolling mill in the same steel mill in addition to a commercially available scrap. These various kinds of scraps are usually handled in groups to some extent according to their shapes and contained components. In the present specification, such grouped scraps are referred to as “brands”. For this reason, the unit price of a brand to which a scrap that has a shape difficult to handle and a high contamination rate of impurities belongs is low.

  The difficulty in handling scraps is that a simple selection is not allowed in which cheap scraps should always be selected and used. That is, the steelmaking furnace can accept scraps of various shapes, but must supply refined steel by refining various components according to the final product. For this reason, the selection of scrap is not limited to its cost, the amount of impurities allowed by the product standards, the amount generated and stored that needs to be balanced with the amount of scrap used, and the scrap transport method, It is necessary to take into account the method of charging the steelmaking furnace.

  Therefore, in general, in the premises of steelworks where steelmaking furnaces are installed, in order to adjust the amount of scrap used, the composition of the molten steel produced in the steelmaking furnace, etc., depending on the scale and location conditions of the steelworks A common storage place for scrap is provided outside or inside the factory where the steelmaking furnace is installed. In general, scraps that are commercially available or generated in the same steelworks are generally unloaded at these common storage locations, and charged into the steelmaking furnace from these common storage locations according to the steelmaking furnace manufacturing plan. It is conveyed to the chute and charged into the steel making furnace as a raw material from this charging chute.

  At this time, considering the operation efficiency of the steelmaking furnace, the transportation of scrap from the place where the scrap is generated to the charging chute to the steelmaking furnace is streamlined and used such as reduction of transshipment work and shortening of the transportation route. Needless to say, it is desirable to make it as simple and easy as possible from the standpoint of optimizing scrap mixing.

  In the past, it has been common practice to reduce the raw material cost by appropriately mixing the scrap to be used.

  For example, Patent Document 1 discloses an invention for systematizing scrap blending instructions to determine the amount of converter scrap blended and to expand the use of inexpensive scrap. In this invention, the scrap blending amount is determined based on the loading allowance determined according to the loading time, price and steel quality for each scrap brand, and then the preparation time is within the constraints of the scrap loading time on the scrap chute. Adjust the amount of converter scrap blending so that it fits.

  Patent Document 2 discloses an invention in which changes in the amount of scrap stock due to the arrival or consumption of scrap are always grasped, and the type of scrap charged into the electric furnace is changed based on the information. According to the present invention, when the trap element (smallly mixed component) is equal to or higher than a predetermined value by quality inspection of the product, the type of scrap supplied to the electric furnace is changed, and the change status is transmitted to the scrap conveying means side.

Furthermore, in Patent Document 3, scrap that has been transported by truck is once received in a scrap yard that is a common storage location adjacent to a steelmaking factory, and the scrap is supplied to an electric furnace via a scrap bucket. In an automatic conveyance system, a system related to a scrap conveyance method and a bucket loading method is disclosed.
JP-A-8-157925 JP 11-255339 A JP-A-6-263252

  However, according to the invention disclosed in either Patent Document 1 or Patent Document 2, nothing is disclosed regarding the transporting of scrap up to the scrap chute, the method of loading the scrap chute, and the bucket. In other words, the invention disclosed in Patent Document 1 or Patent Document 2 merely manages the charging of scraps, and does not consider any rationalization of the transport of scrap from the scrap generation source to the steelmaking furnace.

  Further, Patent Document 3 does not disclose any transport method to the common storage location. Certainly, Patent Document 3 discloses unloading from a truck to a storage location and packing in a bucket, but it is complicated in terms of equipment and requires the use of a special pallet. And it cannot be made easy.

  The present invention has been made in view of the difficulty in handling scrap that the above-described conventional technology has, and in a steelmaking furnace such as a converter or an electric furnace, by simplifying and facilitating the distribution of scrap to be used. An object of the present invention is to provide a method for operating a steelmaking furnace capable of optimally blending the brand and amount of scrap according to product specifications.

The present invention relates to the scrap of raw material in the middle of transport to a common scrap storage site provided in a place different from the steelmaking furnace where the raw material scrap is introduced from a plurality of raw material scrap generation locations in the steelworks . the part of the conveying destination of which, each issue of the material for the scrap in each heat that is planned in advance for each ingot steel species to be refined by the heat of the steelmaking furnaces, on the basis of the planned amount and time, the Changed to transfer directly to the scrap charging chute to the steel making furnace in the same building as the steel making furnace, and unloaded directly to the scrap charging chute and then put into the steel making furnace This is a method for operating a steelmaking furnace.

In the method of operating a steelmaking furnace according to the present invention, a part of the raw material scrap in the middle of the transportation to the scrap common storage is transferred to a scrap charging chute and a temporary storage place for the steelmaking furnace. It is desirable to change it in the middle of conveyance so that it may be conveyed directly.

In these steelmaking furnace operating methods according to the present invention, the scrap for raw material that has been changed in the middle of transportation to be transported directly to the temporary charging place of the steelmaking furnace as well as to the scrap charging chute is mounted on the truck. In addition to being transported, it is desirable that the truck is dropped into the scrap charging chute or temporary storage site.

  According to the present invention, it is possible to minimize scrap logistics waste by sharing steelmaking schedule information from a scrap generation source to a transport truck, which has a great practical advantage.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a method for operating a steelmaking furnace according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an explanatory view schematically showing a flow of scrap at an ironworks in the present embodiment together with a conventional flow. In FIG. 1, the flow of the present embodiment is indicated by a thick arrow, and the conventional flow is indicated by a thin arrow.

  Conventionally, scrap generated from the scrap generation site 1 is transported to a scrap common storage site 2 by truck, and is once classified into brands A to F. Scraps are generally managed by classifying them into brands A to F, for example, according to the difference in the scrap generation place 1, including scrap purchased from the outside as a whole steelworks. Depending on the location conditions of the steelmaking factory 5 where the steelmaking furnace 3 is located, scrap storage / accumulation is performed not only in the scrap common storage area 2 but also in the scrap temporary storage area 4 in the steelmaking factory 5.

  On the other hand, in the steelmaking factory 5 that uses scrap, the brand, amount, and amount of scrap used as a raw material for each heat refined in the steelmaking furnace 3 based on a predetermined steelmaking plan 6 for the molten steel in the steelmaking furnace 3. A plan 7 regarding the charging time is drawn up and scheduled.

  Specifically, in the plan 7, for example, when steel types a to c are respectively melted in this order, the brand and amount of scrap to be used as raw materials in each heat are time-sequentially based on the work schedule of the day. decide. This plan 7 reveals how much scrap of which brand is needed at what time. Making such a plan 7 is referred to as “sheat scheduling” in this specification.

  At that time, it is desirable to make data on the brand and amount of scrap that can be used in advance for each molten steel type, for example, a table. Furthermore, it is also desirable to optimize the composition of the scrap to be used by adding information such as price and availability for each brand to the data.

  Conventionally, according to the plan 7, the scrap is transported again from the scrap common storage site 2 and the scrap temporary storage site 4 in the steelmaking factory 5 to the scrap charging chute 8 by a truck or a lift magnet, and is made into a steelmaking furnace. 3 was thrown.

  For this reason, in the conventional method of operating the steelmaking furnace 3, the route from the scrap generation place 1 to the scrap common storage place 2 or the temporary storage place 4 and then to the scrap charging chute 8 must be passed through. The scrap transshipment occurred many times and the scrap transportation route became long, which inevitably increased the logistics cost.

  On the other hand, in the present embodiment, the scheduled plan 7 is also transmitted to the truck that is transporting the scrap from the scrap generation site 1 to the scrap common storage site 2, and the scrap that matches the plan 7 is mounted. The truck is directly moved to the scrap charging chute 8 of the steel making furnace 3 as it is. As a result, the scrap that matches the plan 7 is directly conveyed from the scrap generation place 1 to the scrap charging chute 8 without passing through the scrap common storage place 2 and the scrap temporary storage place 4.

  According to the present embodiment, when scrap is transported from the scrap generation site 1, priority is given to the scrap that conforms to the brand and amount input in the steelmaking furnace 3, and the material is immediately transported and delivered to the steelmaking furnace 3. For this reason, according to the present embodiment, it is possible to reduce the cost of scrap logistics as much as the ratio of the trucks that go straight to the steelmaking furnace 3 increases.

  As described above, in the present embodiment, at the stage where the plan 7 is scheduled, the information is being transferred from the various scrap generation locations 1 to the scrap common storage 2 in a location different from the steelmaking furnace 3. This is also provided to other trucks, so that the brand and amount of scrap mounted on this truck are confirmed, and it is determined whether or not to go straight to the scrap charging chute 8. However, unlike this embodiment, for example, information on the brand and amount of scrap being conveyed on such a truck is input to a control device (not shown), and this control device uses which truck to insert scraps. You may make it judge and instruct | indicate whether it makes it go to the chute | shoot 8 directly.

When there is a truck carrying a suitable brand and quantity of scrap, the steelmaking furnace 3 located in the same building as the steelmaking furnace 3 from the common scrap storage 2 is used as the transport destination of the truck. Instructed to change to the scrap charging chute 8, the unloading is directly performed on the scrap charging chute 8.

  At this time, not only the scrap charging chute 8 but also the scrap temporary storage place 4 existing in the same building as the steel making furnace 3 or adjacent to the building may be unloaded. The reason for unloading to the temporary scrapping place 4 is that it may be necessary to adjust the weight of the scrap to be added, and it is desirable to secure it as a preliminary / emergency for continuing the operation of the steelmaking furnace 3. is there.

  According to this embodiment, it is possible to change the unloading place of the scrap by the truck without changing the brand of the scrap to be used, so that the effort of transshipment of the scrap and transfer within the steelworks is reduced. As much as possible, the cost of scrap logistics can be reduced. For this reason, the operating cost of the steelmaking furnace 3 can be reduced.

  That is, in the present embodiment, the scrap in the middle of conveyance toward the scrap common storage place 2 provided at a place different from the steel making furnace 3 into which the scrap is input as a raw material from the scrap generation place 1 is converted into the steel making furnace 3. To the steelmaking furnace in the same building as the steelmaking furnace 3 based on the plan of each brand, amount and charging time of each scrap for each heat refined for each molten steel type refined by each heat The scrap charging chute 8 or the scrap charging chute 8 and the temporary placing place 4 of the steel making furnace 3 are directly transferred to the scrap charging chute 8 or the scrap charging chute 8 and the temporary placing place 4 of the steel making furnace 3. The steelmaking furnace 3 is operated by loading it into the steelmaking furnace 3 after unloading.

  Therefore, according to the present embodiment, for example, there are fewer opportunities for transporting scrap to the scrap common storage yard 2, which means that there are fewer opportunities for loading and transporting scrap to the charging chute to the steelmaking furnace 3. Directly connected to Moreover, since there is no change in the brand of scrap used, there is no loss in raw material costs.

  The charging to the steelmaking furnace 3 is not limited to the scrap charging chute 8, but a bucket or the like may be used. Furthermore, if data from the scrap generation site 1 is also taken in and the truck transportation plan is systematized, scrap can be transported more efficiently. In some cases, the need for the common scrap storage site 2 Can be lost.

  Further, in the present embodiment, as described above, since the brand of scrap that is paid out and goes straight to the scrap charging chute 8 of the steelmaking furnace 3 is known, it is mounted on this truck during conveyance by the truck. Measure the total weight of the scrap. And based on this measurement result, scrap is directly delivered from the loading platform of the truck to the scrap making chute 8 to the steel making furnace 3 or to the temporary putting place 4 in the same building as the scrap charging chute 8 and the steel making furnace 3. Adopt a structure that can be dropped.

  FIG. 2 is an explanatory view schematically showing a pit structure that enables direct loading of the scrap charging chute 8 into the steel making furnace 3 by a truck in the present embodiment. FIG. FIG. 2 (b) is a cross-sectional view showing the pit structure. In FIG. 2 (a) and FIG. 2 (b), the place where the scraps of the respective brands A to F are arranged is the scrap temporary storage place 4.

  As shown in FIG. 2 (b), the truck 9 that has transported the scrap from the scrap generation site 1 can pay the scrap directly to the scrap charging chute 8a, 8b or 8c.

  In the example shown in the figure, the upper charging port of the scrap charging chute 8 a, 8 b or 8 c is provided below the running surface 10 of the truck 9. As a result, it is possible to directly perform scrap dispensing from the truck 9 to the scrap charging chute 8a, 8b or 8c without using, for example, a scrap charging crane or the like. When the amount of scrap paid out from the truck 9 is less than the amount of scrap to be used, the scrap of the same brand placed in the temporary storage place 4 is replenished to the scrap charging chute 8a, 8b or 8c. What is necessary is just to supply.

  As a result, it is possible to simplify both the unloading operation of the scrap and the conveying operation in the factory, and the number of scrap reloading operations can be further reduced, so that the scrap logistics can be made more efficient.

  As described above, in this embodiment, in order to reduce the logistics cost of scrap, scraps loaded from the scrap generation place 1 are directly loaded from the loading platform of the truck 9 into the chute 8a, 8b or 8c for scrap charging or scraps. Since it is effective to unload to the temporary storage place 4, the pit structure can be directly discharged from the truck 9 to the scrap charging chutes 8 a, 8 b or 8 c and the scrap temporary storage place 4.

  In other words, in the present embodiment, the schedule 7 of the brand, amount and charging time of the raw material scrap for each heat refined in the steelmaking furnace 3 is scheduled, and the schedule is provided to the truck 9 that is carrying the scrap. Thus, a pit structure is adopted in which the truck 9 is directly sent to the scrap charging chute 8a, 8b or 8c, and the scrap can be paid directly to the scrap charging chute 8a, 8b or 8c to the steelmaking furnace 3. This reduces the cost of scrap logistics.

  However, in order to adjust the weight of the scrap charged into the steelmaking furnace 3, it is effective to temporarily place a certain amount of scrap in the steelmaking factory 5. When replenishing the amount of scrap of each brand supplied to the temporary storage place 4, it is also effective to allow the scrap to be dropped directly from the truck 9 to the storage place of each brand in the temporary storage place 4.

  According to this embodiment, in the steelmaking furnace 3 such as a converter or an electric furnace, it is possible to simplify and facilitate the distribution of scrap to be used, whereby the brand and amount of scrap can be set according to product standards. The steelmaking furnace 3 can be operated while mixing optimally.

  Furthermore, the present invention will be described more specifically with reference to examples.

  In order to eliminate waste of logistics costs associated with the charging of scrap, based on the method of operating a steelmaking furnace according to the present invention described in the above-described embodiment, the planning 7 of scrap brand, amount and charging time, A system for providing this information was constructed, and a pit having a structure capable of dropping scrap directly from the loading platform of the truck 9 was constructed.

  An example of operation within one shift (8 hours) at a steelworks is shown in comparison with the operation in the conventional method. There are three types of scrap to be managed at this time, and the characteristics are shown in Table 1. Further, Table 2 shows the molten steel types. Further, Table 3 shows the melting schedule and used scrap.

  In the example shown in Table 3, there is a restriction on the Cr component of the product of the steel type a to be melted, and the scrap brands A and C generated from the continuous casting machine and the pipe mill are basically not usable. In addition, since the steel type b to be melted has a low charge per charge of 160 tons / charge, the amount of scrap used in terms of heat capacity is limited, and the continuous casting has a relatively large shape. Scrap is difficult to use.

  Table 4 and Table 5 show the number of times the track and lift magnets used in Table 3 are used under such constraints.

  In addition, all the scraps that went straight to the scrap charging chutes 8a to 8c in Table 3 were unloaded at the common scrap storage site 2 and then loaded onto the truck 9 with a lift magnet when necessary. The cargo was unloaded to the temporary storage 4 in the factory 5 and further transported to the scrap charging chutes 8a to 8c with a lift magnet. In the example, the case where the pit structure shown in FIG. 2B was adopted and the case where it was not adopted were investigated.

  According to the present invention, as shown in Table 4, the number of times the track 9 is used can be reduced by 25% compared to the conventional example. This reduction rate is the same for the smelting schedule for other steel types. Thus, reducing the number of times the truck 9 is used is synonymous with reducing the number of necessary trucks 9, and the effect of reducing logistics costs is significant.

  In addition, reducing the number of times the truck 9 is used means reducing the number of times the scrap is loaded, and the number of times the lift magnet is used is simply reduced as much as the number of times of passing through the scrap common storage area 2 is reduced. In addition, if the scrap can be dropped directly from the truck 9 into the scrap charging chute 8a to 8c in the steel factory 5, the use of lift magnets in the steel factory 5 is basically charged. This can be reduced only when the scrap temporary storage 4 is used in accordance with the adjustment of the scrap amount.

  As shown in Table 5, the use of lift magnets in the scrap common storage site 2 can be reduced by the systematization of scrap logistics alone. The reduction effect is significantly increased. When both are combined, as shown in Table 5, the number of times the lift magnet was used could be reduced by about 60% compared to the conventional example.

It is explanatory drawing which shows typically the flow of the scrap in the ironworks in embodiment with the conventional flow. FIG. 2 is an explanatory view schematically showing a pit structure that enables direct loading of a scrap charging chute into a steelmaking furnace by a truck in an embodiment, and FIG. 2 (a) is a plan view showing the pit structure; 2 (b) is a sectional view showing this pit structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Scrap generation place 2 Scrap common storage place 3 Steelmaking furnace 4 Scrap temporary storage place 5 Steelmaking factory 6 Production plan 7 Plan 8 Scrap charging chute 9 Truck

Claims (3)

Part of raw material scrap that is being transported to a common scrap storage site that is located in a different place from the steelmaking furnace where raw material scrap is introduced from multiple raw material scrap generation sites in the steelworks The steelmaking furnace, based on each brand, amount and time plan of the raw material scrap for each heat that was planned in advance for each molten steel type refined by each heat of the steelmaking furnace Changing directly to the chute for scrap charging to the steel making furnace in the same building, and changing the middle of the transfer, unloading directly to the scrap charging chute and then throwing it into the steel making furnace A method of operating a steelmaking furnace. The part of the conveying destination of the feed for the scrap in the middle of conveyance towards the scrap common storage field, together with the said scrap instrumentation necessity chute, in particular transport for transporting directly also to the temporary storage of the steelmaking furnace The method for operating a steelmaking furnace according to claim 1, wherein the method is changed in the middle of the process. The raw material scrap changed in the middle of conveyance to the scrap charging chute as well as to the temporary storage place of the steelmaking furnace is mounted on a truck and conveyed, and from the loading platform of the truck The method for operating a steelmaking furnace according to claim 1 or 2, wherein the steelmaking furnace is dropped into a scrap charging chute or the temporary storage site.

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