WO2009031367A1 - Vertical furnace - Google Patents

Abstract

A vertical furnace having a gas suction port provided in its peripheral wall at furnace top part, designed to conduct operation with raw materials and fuels laid in an intra-furnace area superior to the gas suction port while closing the furnace top part. The vertical furnace is characterized in that (i) the furnace top part at its closure zone is fitted with a steel-made right cylinder for partitioning deposition regions for charged raw materials and fuels and (ii) superiorly to the furnace top, there is provided a raw material and fuel charging unit for dividing raw materials and fuels with different properties and charging them separately into areas inside and outside the right cylinder in cooperation with the right cylinder.

Description

Vertical furnace

Technical field

 The present invention is provided with a charging device for separately charging raw fuels having different properties above the top of the furnace, and clarifying the raw fuel separately charged at the top of the furnace.

The present invention relates to a vertical furnace including a straight cylinder that partitions a deposition region.

Technical background

 Conventionally, pig iron is produced by melting iron sources such as iron scrap, porcelain scrap, pig iron and the like in a vertical furnace (cubora). In this type of vertical furnace, there is no reduction, so there is no need to produce reducing gas at the tuyere, and the coke is burned to secure a heat source necessary for raising or melting the raw fuel.

Usually, in the shaft furnace, the mixture to charging the raw fuel (iron source and co one box), combustion efficiency: T ₀ (= C_〇 _{2 / (CO + C 0 2} ) 4 0~ 5 0% In order to obtain a gas with a 77 _{c Q} of about 40 to 50%, usually use a large diameter coke with a particle diameter of about 100 to 150 mm, Suppresses the solution loss reaction after combustion.

 However, large-diameter coke for porcelain is expensive, and in recent years, attempts have been made to use small-diameter coke such as blast furnace coke in order to reduce fuel costs.

However, when small-diameter coke is used, the endothermic reaction, the loss-of-solution reaction, proceeds and the coke combustion efficiency is reduced by 7? _{E Q.} As a result, the amount of heat required to dissolve the iron source is insufficient, resulting in an Is inevitable. On the other hand, in recent years, in a vertical furnace, self-reducing ore and iron scraps are used as the main raw materials, and the operation of melting iron scraps while reducing the self-reducing ores has been started.

For example, “Goksel et al., Transact ions of the American Foundry Society's Society Vol 85 AFSDes Plaines. III. (1977). P.327-332” describes that in a vertical furnace that also requires a reduction function, the blast temperature 6 It has been reported that operation was conducted at 0 to 0 ° C or less at the tuyere without forming a raceway. Further, Kohyo 0 1 -? 5 0 1 4 0 1 discloses a small diameter coke, and uses a large amount of self-reducible ore lump, dissolving the scrap under the high combustion efficiency 7 _co, complex A melting furnace with a simple furnace structure has been proposed.

However, in vertical furnaces, self-reducing ores and iron scraps are the main raw materials, and a large amount of small-diameter solid fuel (small-diameter coke, blast furnace coke) is used to reduce the self-reducing ores and iron scraps. If the operation to dissolve the solid fuel combustion efficiency 77 _CQ does not decrease, and avoiding hanging from the shelf, it is technically difficult to operate stably for a long time, technically difficult, Was recognized as a technical issue.

Therefore, Japanese Patent Laid-Open No. 10-0 3 6 9 0 6 discloses that an iron source that needs to be reduced, an iron source that only needs to be melted, and a solid fuel are charged into a vertical furnace and provided on the furnace wall. In an operation method in which the following oxygen-enriched air is blown from the tuyere at room temperature or 600 ° C. to reduce and dissolve, is it optimal for reduction and dissolution based on the average metallization rate of the iron source? ? An operation method has been proposed in which the _CQ (gas utilization factor) is obtained and the? 7 _CQ of the exhaust gas is adjusted to the optimum range by adjusting the furnace height of the charge.

However, in the above operation method, it is necessary to find the optimal TUo (gas utilization rate) each time the mixing ratio of the iron source that needs to be reduced and the iron source that only needs to be dissolved changes. Is constrained. In the above operation method, from the top of the furnace, an iron source with a high metalization rate is mixed with solid fuel and charged into the center of the furnace, and an iron source with a low metalization rate is mixed with the solid fuel to surround the furnace. However, it is necessary to adjust the height of the coke bed at the bottom of the furnace.

 In addition, when mixing the solid fuel and the iron source into the furnace center, the weight ratio of C in the solid fuel to Fe in the iron source must be between 0.01 and 0.05. In addition, it is necessary to change the charging level (stock level) of the furnace periphery with respect to the furnace center according to the average metallization rate of the iron source.

 As described above, the operation method proposed in Japanese Patent Application Laid-Open No. 10-0 3 6 90 6 is an operation method that has many control factors and is difficult to employ in actual operation.

In addition, Japanese Patent Laid-Open Nos. 0-9-2 0 3 5 8 4 and 3 5 8 6 3 5 5 disclose that the solid fuel combustion efficiency 7? _{E ()} is not lowered and shelves are avoided. Thus, a raw fuel charging method and a raw fuel charging device have been proposed for the purpose of performing operations efficiently and stably for a long period of time.

 The raw fuel charging method proposed in Japanese Patent Laid-Open No. 0-9-2 0 3 5 8 4 uses self-reducing ores, dust agglomerates, iron sources such as iron scrap, and raw fuels such as small solid fuel. When charging into a vertical furnace, the weight ratio of the iron source Z solid fuel is changed for each charging charge, and the charging is performed separately for the furnace periphery and the furnace center. However, in order to change the weight ratio of the iron source / solid fuel, etc. for each charging charge when charging the raw fuel, it is necessary to take a complicated procedure, which is not necessarily suitable for actual operation. Absent.

Japanese Laid-Open Patent Publication No. 09-203-584 describes a charging mode in which raw fuel is charged by using a charging guide and dividing it into a furnace peripheral part and a furnace central part. (See Fig. 3), however, when the charged raw fuel is deposited on the existing raw fuel, it flows to the periphery of the furnace or the center of the furnace, and does not necessarily deposit in a predetermined area. The desired effect may not be obtained. In addition, the raw fuel charging device proposed in Japanese Patent No. 3 5 8 6 3 5 5 is divided into a conical bell and a plurality of portions in the radial direction, and the lower portion is tapered to have a discharge port at the bottom. Equipped with a horizontally movable raw fuel guide member that selectively feeds raw fuel into the furnace center and around the furnace, but the raw fuel that has passed through the guide device When depositing on the raw fuel, it flows to the periphery of the furnace or the center of the furnace, and does not necessarily deposit in the specified area, and the desired effect may not be obtained.

After all, in the conventional raw fuel charging method and the raw fuel charging device, the divided raw fuel is simply charged, so the divided raw fuel does not accumulate in a predetermined region. As a result, in the operation of a vertical furnace that performs reduction and melting, the combustion efficiency of solid fuel 7? _{E Q} does not decrease, and the operation is carried out efficiently and stably for a long period of time, avoiding shelf suspension. It becomes difficult. Disclosure of the invention

 In view of the fact that the charging mode of the raw fuel affects the operation of the vertical furnace that performs reduction and melting, the present invention separately charges the raw fuel according to the properties from the top of the furnace. The task is to deposit the raw fuel that has been introduced in a predetermined area as intended.

Then, find the means to solve the above problems, without lowering the combustion efficiency 7? _Cc of the solid fuel, and, to avoid hanging shelves, the furnace operation, a long period of time, can be efficiently stably The purpose is to provide a vertical furnace.

The present inventors have provided a gas suction port in the peripheral wall of the furnace top, and in a vertical furnace that operates with the raw fuel in the furnace area above the gas suction port sealed and operated, When considering the means of charging fuel, as mentioned above, the means that focus only on the raw fuel charging mode solves the problem. In view of the fact that it does not lead to this, we have intensively studied including the structure of the top of the furnace where raw fuel is deposited.

 As a result, (i) a steel straight cylinder is provided in the sealing zone at the top of the furnace to define the raw fuel deposition area, and (ii) above the furnace top, in cooperation with the steel straight cylinder. A raw fuel charging device is provided for dividing and charging raw fuels having different properties into and out of the steel straight cylinder, and the divided raw fuel is appropriately loaded into and out of the steel straight cylinder. If so, is the solid fuel combustion efficiency? It was found that the furnace operation can be carried out efficiently and stably over a long period of time without lowering the CQ and avoiding hanging from the shelf.

 The present invention has been made on the basis of the above findings, and the gist thereof is as follows.

 (1) In a vertical furnace that has a gas suction port in the peripheral wall of the furnace top and operates with the raw fuel inside the furnace above the gas suction port sealed at the top of the furnace.

 (i) The steel top cylinder defining the accumulation region of the charged raw fuel is provided in the sealing zone at the top of the furnace, and

 (ii) A raw fuel charging device is provided above the top of the furnace in cooperation with the above steel straight cylinder and charging raw fuels having different properties into the inside and outside of the steel straight cylinder.

A vertical furnace characterized by that.

 (2) The raw fuel charging device is

 (ii- 1) A conical guide member having a bottom surface that closes the opening of a steel straight cylinder,

 (ii-2) Inverted conical guide member having a bottom opening communicating with the opening of the steel straight cylinder, and

 (ii-3) Provided with an attachment / detachment mechanism for attaching / detaching the conical guide member or the inverted conical guide member directly above the steel straight cylinder.

The vertical furnace according to (1) above, characterized in that: (3) The vertical furnace according to (2), wherein the attaching / detaching mechanism is driven according to a raw fuel charging schedule.

 (4) The attachment / detachment mechanism rotates the conical guide member and the inverted conical guide member to move from the retracted position directly above the steel straight cylinder in a vertical plane around the fulcrum set on both sides of the furnace top. The vertical furnace according to (2) or (3), further comprising a mechanism.

 (5) The rotating mechanism according to (4), characterized in that a weight that balances the weight of the guide member is provided on the opposite side of the conical guide portion and the inverted conical guide member across the fulcrum. Vertical furnace.

 (6) The attaching / detaching mechanism rotates and moves the conical guide member and the inverted conical guide member from the retracted position directly above the steel straight cylinder in a horizontal plane around a fulcrum set on both sides or one side of the furnace top. The vertical furnace according to (2) or (3), further comprising a rotating mechanism to be operated.

 (7) The attachment / detachment mechanism includes a reciprocating mechanism for reciprocating a long structural member mounted on both ends of the conical guide member and the inverted conical guide member in a horizontal plane with the furnace top interposed therebetween. The vertical furnace according to (2) or (3), characterized in that it is characterized.

 (8) The (2) or (2), wherein the attaching / detaching mechanism includes a reciprocating mechanism for reciprocating a carriage on which the conical guide member and the inverted conical guide member are placed with the furnace top interposed therebetween. 3) A vertical furnace as described in 3).

 (9) The vertical furnace according to any one of (1) to (8), wherein a level measuring device for measuring the level of raw fuel inside and outside the steel straight cylinder is provided at the top of the furnace. .

 (10) The saddle type according to any one of (1) to (9), wherein the steel straight cylinder is placed on a support member installed on the inner wall of the furnace top opening. Furnace.

(11) Open area of the steel straight cylinder and the space between the furnace top inner wall and the steel straight cylinder The vertical furnace according to any one of (1) to (10), wherein the area ratio is set in accordance with a charging ratio of raw fuels having different properties.

 (1 2) The vertical furnace according to (1 1), wherein a ratio of an opening area of the steel straight cylinder to an area between the furnace top inner wall and the straight cylinder is approximately 1/2.

 (1 3) The vertical furnace according to any one of (1) to (12), wherein the steel straight cylinder is made of stainless steel.

According to the present invention, there is provided a vertical furnace capable of efficiently and stably performing a furnace operation for a long period of time without lowering the solid fuel combustion efficiency 7 _{e Q} and avoiding shelf hanging. be able to. Brief Description of Drawings

 FIG. 1 is a view showing an embodiment of a vertical furnace (invention furnace) according to the present invention.

 FIG. 2 is a diagram showing a charging mode in which the attachment / detachment mechanism is driven and the inverted conical guide member or the conical guide member is placed above the steel straight cylinder. (A) shows the charging mode with the inverted conical guide member placed above the steel straight cylinder, and (b) shows the charging mode with the conical guide member placed above the steel straight cylinder. .

 Fig. 3 is a diagram schematically showing the state of raw fuel accumulation in the vertical furnace. BEST MODE FOR CARRYING OUT THE INVENTION

 The present invention will be described with reference to the drawings.

Fig. 1 shows an embodiment of the vertical furnace (the present invention furnace) according to the present invention in which the raw fuel is not charged in the furnace. The vertical furnace 1 basically includes a furnace body 2 having an upper tuyere 6 a and a lower tuyere 6 b at the lower part, and an upper part of the furnace body 2. The gas suction part 4 is provided in the gas suction part 4 and the furnace top part 3 is provided so as to penetrate through the gas suction part 4 and seal the upper part of the furnace body 1 with raw fuel (not shown) accommodated therein. .

 The furnace top 3 is made of a steel shell, but the outside of the portion inserted into the gas suction part 4 is covered with a refractory.

 As shown in Fig. 1, the tuyere is basically a force that provides two stages of upper tuyere 6a and lower tuyere 6b in the height direction of the furnace. Provided at a height position directly above the surface of the filled coke bed 20, and the lower tuyere 6 b is provided at a height position within the coke bed 20. The tuyere diameter is set so that the blowing speed is slower than the blast furnace so that the raceway is not created at the tuyere. Note that the present invention is not limited to a two-stage tuyere, and can be performed with a single-stage tuyere depending on the air blowing conditions.

When air is blown from the upper tuyere 6a and lower tuyere 6b, the lower tuyere 6 blows in air at room temperature or 600 ° C or lower, mainly burning the coke. In addition, air at room temperature is blown from the upper tuyere 6 a to burn the CO gas generated by the combustion loss reaction (endothermic) of some combustion gases (co ₂ ) and coke, Compensation for decrease in heat of fusion of iron source due to solution loss reaction (endothermic).

 When the first stage tuyere is blown, the lower tuyere is installed at the same height as the lower tuyere 6 b to promote the combustion of coke and increase the heat of fusion of the iron source. It is necessary to enrich oxygen in the air blown from 6b at room temperature or 600 ° C or lower, and increase the oxygen concentration.

On the other hand, when the air is blown from the two-stage tuyere shown in Fig. 1, the amount of heat can be compensated by the air blown from the upper tuyere 6a. Enrich the air with oxygen, It is not always necessary to promote the combustion of coke and increase the heat of fusion of the iron source.

 The raw fuel to be reduced or dissolved in the vertical furnace 1 is cut out from each raw material hopper (not shown), weighed by a weighing device (not shown), and then put into a baguette 9 as a charging device. It is accommodated and carried above the top 3 of the furnace, and from the top 3 of the vertical furnace 1 via the packet 9, onto the cox bed 8 formed at the bottom of the vertical furnace 1, The solid fuel and the iron source are charged in a layered or mixed state.

 As the fuel, a small-diameter carbonaceous solid fuel is used, but a large amount of small-diameter coke (blast furnace coke) is mainly used. As raw materials, hot briguet reduced iron (MBI), direct reduced iron (DRI), iron scraps, molds and other iron sources that only need to be dissolved, self-reducing ores (including C agglomerates), Use an iron source that requires reduction, such as reduced iron with a low metallization rate.

 In the furnace of the present invention, a steel straight cylinder 7 whose lower end extends to the vicinity of the upper end of the gas suction part 4 is supported by a straight cylindrical support member 8 inside the furnace top part 3. Raw fuel with different properties accumulates inside and outside the cylinder 7.

 In the furnace of the present invention, a steel straight cylinder is attached inside the top of the furnace, which is a structural feature for efficient and stable operation over a long period of time. The straight steel cylinder is preferably made of stainless steel with excellent wear resistance.

 The opening area of the steel straight cylinder is set according to the ratio of the amount of raw fuel charged separately inside and outside the steel straight cylinder 7.

As shown in FIG. 1, the steel straight cylinder is attached to the inside of the furnace top portion 3 with a straight cylinder support member 8, and can be appropriately replaced. In the furnace of the present invention, even if a large amount of small-diameter coke (blast furnace coke) is used, the combustion efficiency of solid fuel 77 _{e Q} is not reduced, and shelf operation is avoided by avoiding shelf hanging. In order to perform efficiently and stably for a long period of time, the raw fuel is divided according to the properties, and charged and deposited inside and outside the steel straight cylinder.

 Specifically, an iron source that requires only melting, or the iron source and solid fuel (hereinafter sometimes referred to as “melting raw fuel”) is charged into a steel straight cylinder 7 and deposited. On the other hand, the iron source that needs to be reduced, or the iron source and solid fuel (hereinafter sometimes referred to as “reducing raw fuel”) are charged between the inner circumference of the furnace top and the steel straight cylinder 7. And deposit.

 FIG. 1 shows an inverted conical induction member 10 for charging raw raw fuel into the steel straight cylinder 7 in cooperation with the steel straight cylinder 7 attached to the inside of the furnace top 3. .

 As shown in the figure, the inverted conical guide member 10 is provided with an opening having a diameter substantially the same as the diameter of the steel straight cylinder 7 at the bottom, so that the raw melt fuel contained in the bucket 9 is Passing through the bottom opening of the inverted conical guide member 10, the steel straight cylinder 7 is charged and deposited.

 Fig. 1 shows the conical guide member used for charging the reducing raw fuel between the inner circumference of the top of the furnace and the steel straight cylinder 7 1 1 The force is retracted to the retracted position. The inverted conical guide member 10 and the conical guide member 11 are placed above the steel straight cylinder 7 from the retracted position by the attachment / detachment mechanism according to the raw fuel charging schedule.

The conical guide member 11 has a bottom portion that is large enough to fit within the furnace top, and a conical bottom portion having a bottom surface substantially the same diameter as the diameter of the steel straight cylinder 7 is formed at the center thereof. An opening through which raw fuel passes is formed in Fig. 2. A charging state in which a material or a conical guide member is placed above a steel straight cylinder is shown. Fig. 2 (a) shows the charging mode with the inverted conical guide member placed above the steel straight cylinder, and Fig. 2 (b) shows the setup with the conical guide member placed above the steel straight cylinder. An entry mode is shown.

 2 (a) and 2 (b), a guide member holding frame 14 for holding the inverted conical guide member 10 and the conical guide member 11 on the base 18 provided on the work floor. Rotating shaft fixing member 1 6 for fixing the rotating shaft 1 5, a hydraulic mechanism 1 2 connected to the vicinity of the rotating shaft 1 5 of the guiding member holding frame 1 4, and an inverted conical guiding member 1 0 or cone When the cylindrical guide member 11 is placed on the upper part of the steel straight cylinder 7, support members 17 that support both ends of the guide member holding frame 14 are arranged.

 A weight 13 for smoothly rotating the guide member holding frame 14 by the hydraulic mechanism 12 is attached to one end portion of the guide member holding frame 14.

 Fig. 2 (a) shows the inverted conical guiding member 10 0 force placed at the top 3 of the furnace above the steel straight cylinder 7, retracted to the conical guiding member 1 1 force retracted position, and the packet (not shown) The bottom part of the steel is opened, and the raw material fuel X is inserted into the steel straight cylinder 7.

 When the required amount of raw melt fuel X has been charged, the hydraulic mechanism 12 is driven, and as shown in Fig. 2 (b), the inverted conical guiding member 10 is retracted to the retracted position, and the conical guiding is performed. The member 11 is placed above the straight cylinder 7 made of steel, the bottom of the packet (not shown) that stores the reducing raw fuel Y is opened, and the charging of the reducing raw fuel Y is started.

Since the hydraulic mechanism 1 2 is configured to be controlled by a hydraulic mechanism control device (not shown), the hydraulic mechanism 1 2 is driven according to the raw fuel charging schedule to start operation and during operation. Raw fuels with different properties (dissolved raw fuel X and reduced raw fuel Y) Insert into the zone (inside and outside of the steel cylinder 7). This is a feature of the furnace of the present invention.

 In addition, in Fig. 2, as the attachment and detachment mechanism, a conical induction member and an inverted conical induction member are used to rotate the steel straight from the retraction position within the vertical plane around the rotation shafts (fulcrum points) set on both sides of the furnace top. The rotating mechanism is shown in which it is moved directly above the cylinder and placed. However, the placement and withdrawal of the conical guiding member and the inverted conical guiding member are not limited to this rotating mechanism.

 The rotation mechanism may be a rotation mechanism that rotates and moves the conical guide member and the inverted conical guide member from the retracted position to the top of the right cylinder around the fulcrum set on both sides or one side of the furnace top. .

 Further, the attachment / detachment mechanism may include a reciprocating mechanism that reciprocates a long structural member placed on both ends of the conical guide member and the inverted conical guide member in a horizontal plane with the furnace top interposed therebetween. Alternatively, it may be provided with a reciprocating mechanism for reciprocating the carriage on which the conical guide member and the inverted conical guide member are placed with the furnace top interposed therebetween.

 Fig. 3 shows the state of deposition of dissolved raw fuel X and reducing raw fuel Y inside the vertical furnace in operation. In the furnace of the present invention, raw fuel is deposited on the top 3 of the furnace located above the gas suction part, and by this deposition, a sealing band is formed on the top of the furnace to seal the top of the furnace. ”) To operate.

 The iron source in the raw fuel charged from above the top of the vertical furnace 1 is dissolved by the combustion heat of coke (C) due to oxygen in the air blown from the tuyere while descending the furnace. Iron oxide partially contained in the iron source is reduced with reducing gas (CO), solid carbon (C) or carbon in hot metal (C), and further drops coke bed 20 Accumulate at the bottom of the furnace.

The level of the top surface of the bottom of the bottom of the furnace bottom is the storage level provided outside the furnace. There is a connecting pipe 2 3 that communicates with the flange 2 2, and the hot metal collected at the bottom of the furnace inside the furnace flows through the connecting pipe 2 3 to the storage section 2 2 outside the furnace, After being separated into hot metal (slag) in the upper layer and hot metal in the lower layer, the hot metal in the lower layer is taken out from the outlet 21.

 The smelting reduction region where the iron source is melted and partially reduced mainly consists of a range in the furnace height direction of about 1 to 2.5 m above the surface of the coke bed 8 (bucket). (Equivalent to approximately 1 to 2.5 charges of raw fuel contained in the fuel 7).

 Even if the raw fuel is classified into the vertical furnace according to the properties and charged into the specified area, it will flow into other areas or fall down inside the furnace due to collision with existing deposited raw fuel. If mixed and lowered during the process, the raw fuel for reduction may not be reduced, or it may be suspended from the shelf and air permeability will deteriorate, resulting in a situation where the raw material for dissolution does not dissolve sufficiently. In the furnace of the present invention, the molten raw fuel X and the reduced raw fuel Y charged separately inside and outside the steel straight cylinder 7 are accumulated without intermixing with each other inside and outside the steel straight cylinder 7. So, during operation, it descends without intermingling with each other. That is, the molten raw fuel X and the reduced raw fuel Y form a downward flow without interfering with each other inside and outside the steel straight cylinder 7.

 Smelting raw fuel X and reducing raw fuel Y come into contact after passing through the steel cylinder 7, and even if some mixing occurs, the respective downflows continue, and the main body of the furnace of the present invention In the interior of 2, a very orderly raw fuel accumulation state is realized, in which the dissolved raw fuel X is deposited in the central portion, and the reduced raw fuel Y is deposited around the central portion. This is the greatest feature of the present furnace.

In the operation of a vertical furnace, normally, air below 60 ° C (which may be enriched with oxygen) is blown from the lower tuyere 6 and C + 0 ₂ → 2 With CO, reducing gas is generated, reducing raw fuel X is reduced, and air at normal temperature is blown from the upper tuyere 6 a, and an exothermic reaction of 2 C 0 + 0 ₂ → 2 C 0 ₂ The melting raw fuel X is melted by securing the amount of heat necessary to dissolve the raw melting fuel X.

 As a matter of course, the stack height (stock level) of the raw fuel inside and outside the steel cylinder decreases as the dissolved raw fuel X and reduced raw fuel Y fall during operation. For this reason, in order to stably melt the raw fuel while sealing the top 3 of the furnace, it is measured with a level meter (not shown) attached to the top 3 of the furnace, and the stack height level (stock level) of the raw fuel is measured. To control the raw fuel charging timing so that the fuel is maintained at a predetermined level.

In the furnace of the present invention, as described above, an extremely orderly raw fuel accumulation state is realized in the furnace, so that even if a large amount of small diameter coke is used, the reduction efficiency by the reducing gas, and The melting efficiency by reaction heat is drastically improved, the combustion efficiency of solid fuel T] _CQ is not lowered, and shelf operation is avoided and the furnace operation is carried out efficiently and stably for a long period of time. Can do. Example

 Next, examples of the present invention will be described. The conditions of the examples are one example of conditions adopted to confirm the feasibility and effects of the present invention, and the present invention is based on this one example of conditions. It is not limited. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.

 (Example 1)

As an example of the invention, when operating using an iron source and solid fuel (coix) under the raw fuel compounding conditions shown in Table 1, The gas at the top of the furnace when the turn is charged from the top of the vertical furnace shown in Fig. 1 in the charging cycle of the raw fuel A 1—A l—A 2 and the operation is continued for 7 days. Utilization rate (7) _co ), furnace top exhaust gas temperature (in), furnace pressure (h P a), blowing pressure (k Pa), number of wind reductions (times), number of pauses (times), production rate (TZH ) Was measured. That is, the iron source is 3 charge 1 cycle of A 1-A 1-A 2 and the average ratio of blending is 70% high metallization rate iron source shown in Table 1, low metallization rate iron source Operation was carried out with a charge of 30%.

 In addition, as a comparative example, using a conventional vertical furnace, the raw material composition pattern of B shown in Table 2 was continuously added, and the vertical furnace shown in Fig. 1 was charged, and the operation was continued for 7 days. Furnace top exhaust gas utilization rate (TUa), furnace top exhaust gas temperature (° C), furnace pressure (h Pa), blowing pressure (k Pa), number of wind reductions (times), number of times of rest (times), The production rate (T / H) was measured in the same manner as the invention example. In other words, the above-mentioned operating factors were measured by repeatedly charging and operating the iron source at a mixing ratio of 70% high metallization rate iron source and 30% low metallization rate iron source without separate charging. .

 The results are shown in Table 3.

Note that the gas utilization rate of the furnace top exhaust gas? _{E Q} (TOP) is

7? _Co (TOP) = C_〇 ₂ content in the flue gas [vol%] / (CO content in the exhaust gas [vol%] + C_〇 ₂ content in the flue gas [vol%])

Defined by

 The average metallization rate M is

 M == Metal iron in iron source (M. F e) (mass%) Total iron in Z iron source <T. F e) (mass%)

Defined by

table 1

* Indicates average metallization rate, and C indicates carbon content.

Table 2

 High metallization rate iron source Low metallization rate iron source Solid fuel Charging 1 Place Raw fuel conditions Scrap Dust pellet Blast furnace coke

 (tXch) (t / ch) (t / ch)

A1 4. 2 0. 5 0. 9 Center

A2 2. 6 0. 8

B 2. 8 1. 2 0. 87 No section charge

Table 3

As shown in Table 3, using the sorting and charging device of the present invention, the composition of the raw fuel charged in the center and the periphery is changed, and in the center there is no need for reduction. In Invention Example 1 in which a dust pellet that is reduced and has a small solid size is charged in the periphery, the iron source is supplied using solid fuel containing 100% by mass of blast furnace coke. When melting, keep the average furnace wind pressure at a stable operating level, minimize the number of wind reductions and pauses due to wind pressure rise, maintain high productivity throughout the period, and produce hot metal I was able to.

 On the other hand, in Comparative Examples 1 and 2 shown in Table 3, scrap and dust pellets per charge are equal to the average value of one cycle of Invention Example 1 without using the sorting and charging equipment of the present invention. This is an example of operation that was charged so that

 In Comparative Example 1 operated under the same air blowing conditions as Invention Example 1, the average furnace wind pressure became high, the operation became unstable due to the increase in wind pressure, and there was a situation where it was forced to reduce or stop wind. It occurred at a high frequency and productivity decreased over the period.

 In Comparative Example 2, which aimed at more stable operation by lowering the average furnace pressure, it was forced to operate with a lower air flow per hour than in Inventive Example 1, so compared with Comparative Example 1. Although the frequency of unavoidable operation due to the increase in wind pressure has decreased, the productivity during the period has become much lower than in Invention Example 1 due to the decrease in dissolution speed. is there.

As described above, when the present invention is applied, operation is performed by using a large amount of inexpensive blast furnace coke as a solid fuel, using raw materials such as dust pellets that require reduction and have a small solid size at a high blending ratio. When doing so, it is possible to stably produce pig iron while maintaining high productivity while maintaining the furnace wind pressure at a stable operating level, avoiding wind reduction and resting as much as possible. 063074

Industrial applicability

As described above, according to the present invention, the furnace operation can be efficiently and stably performed for a long period of time without lowering the solid fuel combustion efficiency 7 _{e D} and avoiding the shelf suspension. A vertical furnace can be provided. Therefore, the present invention has great applicability in the steel manufacturing industry.

Claims

1. In a vertical furnace equipped with a gas suction port in the peripheral wall of the furnace top and operating with the raw fuel in the furnace area above the gas suction port sealed  (i) The steel top cylinder defining the accumulation region of the charged raw fuel is provided in the sealing zone at the top of the furnace, and  Contract  (ii) A raw fuel charging device is provided above the top of the furnace in cooperation with the steel straight cylinder and charging raw fuels having different properties into the inside and outside of the steel straight cylinder. A vertical furnace characterized by that.  2. The raw fuel charging device is  (i i-1) A conical guide member having a bottom surface closing the opening of a steel straight cylinder,  (ii-2) An inverted conical guide member having a bottom opening communicating with the opening of the steel straight cylinder, and  (ii-3) Provided with an attachment / detachment mechanism for attaching / detaching the conical guide member or the inverted conical guide member directly above the steel straight cylinder. The vertical furnace according to claim 1, wherein:  3. The vertical furnace according to claim 2, wherein the attaching / detaching mechanism is driven according to a raw fuel charging schedule.  4. The attachment / detachment mechanism is a rotating mechanism that moves the conical guide member and the inverted conical guide member from the retracted position to the position directly above the steel straight cylinder in the vertical plane around the fulcrum set on both sides of the top of the furnace. The vertical furnace according to claim 2 or 3, characterized by comprising: 5. The rotating mechanism according to claim 4, further comprising: a weight that balances the weight of the guide member on the opposite side of the conical guide portion and the reverse conical guide member across the fulcrum. Vertical furnace. 6. The attaching / detaching mechanism rotates and moves the conical guide member and the inverted conical guide member from the retracted position directly above the steel cylinder in the horizontal plane around the fulcrum set on both sides or one side of the furnace top. The vertical furnace according to claim 2 or 3, further comprising a rotating mechanism.  7. The attachment / detachment mechanism includes a reciprocating mechanism that reciprocates a long structural member having a conical guide member and an inverted conical guide member placed on both ends in a horizontal plane with the top of the furnace sandwiched therebetween. A vertical furnace according to claim 2 or 3.  8. The attachment / detachment mechanism includes a reciprocating mechanism that reciprocates a carriage on which the conical guide member and the inverted conical guide member are mounted with the top of the furnace sandwiched therebetween. The vertical furnace described in 1.  9. The vertical furnace according to any one of claims 1 to 8, wherein a level measuring device for measuring the level of raw fuel inside and outside the steel straight cylinder is provided at the top of the furnace.  10. The vertical furnace according to any one of claims 1 to 9, wherein the steel straight cylinder is placed on a support member installed on an inner wall of a furnace top opening.  1 1. The ratio of the opening area of the steel straight cylinder to the area of the furnace top inner wall and the steel straight cylinder is set in accordance with the charging ratio of raw fuels having different properties. A vertical furnace according to any one of claims 1 to 10.  12. The vertical furnace according to claim 11, wherein the ratio of the opening area of the steel straight cylinder to the area between the top wall of the furnace top and the straight cylinder is approximately 1 Z 2.  13. The vertical furnace according to any one of claims 1 to 12, wherein the steel straight cylinder is made of stainless steel.