TR201613510T1 - Method of loading raw material into blast furnace. - Google Patents

Abstract

In a method for loading blast furnace raw material containing ore material and coke into a blast furnace 22 using a rotary groove 26, the blast furnace raw material is provided as a coke layer 4 and an ore layer 5 without mixing the ore material with the coke. or a coke layer (4) and a mixture of coke and ore material formed by mixing a portion of coke with the ore material. When the coke layer 4 loaded into the blast furnace 22 per charge reaches the furnace core 22b, the ratio of the minimum thickness of the coke layer 4 in the furnace core 22b to the arithmetic mean particle size of the coke is suitably limited and the coke layer 22b in the furnace core 22b is suitably limited. 4) the average thickness is limited to 190 mm or less. This results in a stable blast furnace 22 operation as well as increased reduction efficiency with a thinner ore layer 5.

Description

DESCRIPTION METHOD OF LOADING RAW MATERIAL TO THE BLAST FURNACE TECHNICAL FIELD The invention relates to a blast furnace raw material loading method.

INFORMATION ABOUT THE INVENTION In recent years, COZ emissions have been reduced to prevent global warming. reduction requests were made. In the iron and steel industry, especially blast furnaces account for approximately 70% of COZ emissions responsible for reducing COZ emissions in blast furnaces. requests have been made.

Typically, sintered ore, pellet, lump ore, etc. ore like material and coke in layers over the top of a blast furnace. it is loaded alternately and an air conditioner is used to obtain pig iron. Combustion gas is injected through the hole. high furnace loaded high The coke and ore material, which constitute the raw material of the kiln, from above it descends to the core of the kiln and the ore is subjected to tempering and the temperature of the raw material increases. ore due to temperature increase material layer gradually deforms and the furnace while filling the voids in the bulk ore material that the permeability resistance inside the core is very high and immediately forms a sticky layer where there is no gas flow.

Reducing agent used in blast furnace (e.g. coke, pulverized COz in the blast furnace by reducing the amount of gas (coal or natural gas) emissions can be reduced. However, in such a case, the ore It is important to increase the reduction efficiency of the layer.

A known method to increase the reduction efficiency of the ore layer method e.g. “Zairyo to purosesu” (Current advances in materials and processes), as described in volume 63, page of the ore layer to reduce the amount of unreduced ore. It is a method of reducing the thickness.

If the thickness of the ore layer is reduced, the coke The thickness of the layer is also reduced. However, the thickness of the coke layer decreases, the permeability of the sticky region where the ore softens and melts resistance increases. The permeability resistance of the adhesive layer, all high significantly affects the permeability of the oven and Operation of stable blast furnace with increase in permeability resistance has been experimentally known to inhibit

In the blast furnace, especially in the sticky zone, the permeability resistance To prevent the increase in temperature and to ensure a stable blast furnace operation, Various studies on the thickness of the lower limit layer of the root layer has been executed. For example, “Tetsu to hagane (Iron and steel), vol. 87, no. 5, pages 342- According to ”, the bottom of the coke layer in the furnace core the limit layer thickness is approximately 190 mm° on average and a small layer thickness is less than the permeability resistance of the adhesive zone. increases and prevents a stable blast furnace operation.

JP H7-1, regional thinning of coke layers middle layer per coke layer in the furnace throat to prevent coke with a thickness of 60 cm (600 mm) or more distribution control for the loaded material to adjust the amount of describes a blast furnace with the method

between the kiln throat where the raw material is loaded and the adhesive zone Since the inner diameters of the kiln core in which it is formed are different, the kiln the thickness of the coke layer in the throat typically It is approximately 2.2 times the thickness of the coke layer.

JP H6-1, permeation resistance in the adhesive region the thickness of the coke layer in the oven core in order to prevent it from increasing Operating a blast furnace to set to 250 mm or more explains the method.

Oven for stable blast furnace operation as described above Predetermined average root layer thickness in the core or more thick and real blast furnace operation, average coke layer thickness in the furnace core at least approximately 190 ni and depending on the conditions at least 250 mm It was carried out by loading coke in this way.

Mixing coke into the ore material layer It is also known to be effective in increasing the permeability resistance and Various studies have been reported to determine the appropriate mixing state. has been made. For example, JP H is a coreless blast furnace ore. coke feeding to the ore hopper on the exit side from the hoppers, a Coke is stacked on the ore on the conveyor and a rotary a furnace of these for loading ore and coke into the blast furnace from the chute explains its loading into the upper silo.

JP separates ore and coke into kiln top silos. and three batches at the same time: regularly one batch for loaded coke, one batch for centrally loaded coke and coke and ore to form a batch for mixed cargo explains how to load them at the same time as mixing.

JP FAQ-, an unstable form of sticky region and lower near the central zone during the operation of the blast furnace to achieve a gas utilization rate and operational safety and thermal efficiency before all your ore and tobacco coke is loaded into the blast furnace to increase raw material loading into a blast furnace where the tainain is mixed first explains the method.

JP Improving reactivity with mixed coke highly reactive odor according to J IS M 8713 as a means of achieving the effect measured low order reduction, ie low JIS mixing with ore with reducibility and thus low reactive high, which allows the ore to react with high data describes a technique that increases reactivity in the oven.

Many technical reports for mixing coke in the ore layer has been made. However, even in the case of coking into the ore layer the root layer required to ensure the permeability of the adhesive zone thickness has not yet been precisely defined.

REFERANCE LIST Patent Literatures PTL 1: JP H7-18310 A PTL 2: JP H6-1364l4 A PTL 3: JP H3-211210 A PTL 5: JP FAQ-079810 A PTL 8: JP H8-189926 A Non-Patent Literatures NPL 1: “Zairyo to purosesu” (Current advances in materials and processes), volume 63, page 894 (2000) NPL 2: “Tetsu to hagane” (Iroii and steel), vol. 87, no. 5, pages 342- 349 (2001) NPL 3: “Tetsu to hagane” (Iron and steel), vol. 79, no. 8, pages 927- 933 (1993) (Technical problem) The above mentioned sticky area in the oven core in real operation It is extremely difficult to measure the permeability resistance. Permeability To evaluate the resistance of the gas flow in the blast furnace, accurately on a device that simulates the adhesive zone. should be created.

The blast oven adhesive zone consists of two layers: softening which shrinks and therefore has a very high permeation resistance a layer of ore sticky and non-softening and non-shrinking therefore a coke with a low permeation resistance layer. Therefore, since the gas flow in the sticky region], the coke passes through the layer. Therefore, the blast furnace is sticky. to simulate the gas flow in the must be created.

To achieve this, previously published Japanese Patent Application No. 2013- ” by us ” a blast furnace sticky zone simulating iron ore and/or sintered ore and coke a sample containing a sample filled container that can be filled A furnace in which a heating oven and a gas heating oven are placed in parallel. sample of gas, which has a structure and is heated in a gas heating oven. The sample in the filled container in the lateral direction through the filled layer horizontally circulated reactor” is described.

This reactor, simulating the sticky zone of the blast furnace, flowing horizontally through the filled layer and at the same time to the ore It has a structure in which a vertical load is applied. Such a build lateral gas flow in the blast furnace sticky zone, i.e. high with conventional appliances simulating the oven sticky zone correct gas flow near the sticky area that cannot be formed. (for example, JP H and “Tetsu to 3)). Blast furnace sticky zone matching that of real equipment The permeability resistance can be measured in this way.

With the use of the reactor mentioned above, the furnace core traditionally for the gas permeability of the adhesive zone by determining the control factor(s) that cannot be determined and By designing the optimum layer structure, with a thinner ore layer achieve both stable blast furnace operation and increased reduction efficiency. provide a method of loading raw materials into a blast furnace to may be useful.

(Problem Solution) Simulating the blast furnace sticky zone described in PTL 7 With the use of the reactor, the blast furnace raw material is transferred to the blast furnace. loading without mixing coke and ore material and at the same time Changing the film thickness of the coke layer and the ore layer gas flow near the sticky region and intensive work by us on permeability resistance has been executed.

The ore of the blast furnace raw material with coke for a person in the blast furnace mixing and loading the coke layer at the same time and coke and ore material mixed layer (in this document hereinafter referred to as the "mixed layer") gas flow near the adhesive area and On the permeability resistance of the adhesive zone, it is also heavily influenced by us. the study was carried out.

As a result, the average root layer thickness traditionally possible even in a case where it is less than the accepted lower bound in the adhesive zone to ensure the minimum layer thickness gas permeability is ensured and with minimum coke layer thickness. setting the arithmetic mean coke particle size ratio in case of stable blast furnace operation is possible by us. has been discovered. At the same time, the coke layer thickness is thus thinner layer of ore layer or mixed layer can be done, thus contributing to the increase of reduction efficiency. found to be available.

In addition, a portion of coke as a mixed layer with ore material mixed gas permeability of the adhesive zone in case of According to the root mixture ratio in the layer and root layer thickness changes, these relationships are controlled appropriately and become more stable. both blast furnace operation and a reduction in coke It has been discovered by us that it can be obtained.

The invention is based on the above-mentioned discoveries and further work.

For this reason, we provide the following: 1. To load raw material into a blast furnace, with ore material blast furnace feedstock containing coke using a rotary chute blast furnace loading and blast furnace raw material a coke made from mixing high-fired coke with ore material layer and an ore layer or as a coke layer and a coke formed by mixing part coke and ore material and The ore material is loaded as a mixed layer, the blast furnace raw from mixing high-fired coke and ore material coke layer loaded in the blast furnace per charge when it reaches the core of the blast furnace, the coke layer in the kiln core arithmetic mean particle of coke with minimum thickness the ratio of its magnitude with the interval defined by Formula 1 below limited or the blast furnace raw material is high loading the furnace by mixing a portion of coke with ore material limited to the range defined by Formula 2 below. is the average layer thickness of the coke layer in the furnace core. limited to 190 mm or less, Lcmini/Dc 22 (l) Lom/Dc 2-0.0063 Ckar. + 2 (2) Ckarfin in these formulas, coke mix in kg/t in mixed layer rate, Lcm, high per charge in mm in the oven core The minimum coke layer loaded in the furnace and the Dc”, coke mm A method in which the arithmetic mean particle size is in . 2. A blast furnace raw material described in point 1 above to load, the blast furnace raw material is blast furnace coke layer and a part of coke and ore material is mixed. The coke and ore material formed as a mixed layer blast furnace per charge in the oven core. average layer thickness of the loaded coke layer, mixed Depending on the coke mix ratio in the layer, the following Formula 3° is limited to a defined range, in this formula, the coke mix ratio in Ckarhn kg/t and LCm_” in the furnace mm of the coke layer loaded in the blast furnace per charge in the core A method in which the average layer thickness in terms of 3. A blast furnace raw material described in point 2 above For loading, the coke mix ratio (Ckar.) is 80 kg/t or more. the method it is.

(Advantageous Effect) In the invention, each of the increased reduction efficiency with stable blast furnace operation both can be obtained. In fact, the blast furnace raw material has high loading the furnace by mixing a portion of coke with ore material COZ emissions can be reduced by reducing the amount of coke. BRIEF DESCRIPTION OF THE DRAWINGS In the attached drawings: Figure 1 shows a reactor simulating a blast furnace sticky zone. It is a seinatic diagram showing

Figure 2 shows the blast furnace raw material blast furnace coke and ore a coke layer and an ore layer without mixing the material with the coke layer thickness (Lc) arithmetic mean coke particle size (Dc) ratio (Le/Dc) It is a graph of the permeability resistance at 1400°C according to

Figure 3A shows the sticky region in the case of a thick coke layer. A schematic showing the way smelted ore enters the coke layer is the diagram.

Figure 38 shows that in the sticky region if the coke layer is thin. A schematic showing the way smelted ore enters the coke layer is the diagram.

Figure 4, the arithmetic mean coke particle thickness (LC) of the coke layer According to the size (Dc) ratio (LC/Dc), each coke mix It is a graph of the permeation resistance at 1400°C.

Figure 5 shows that when a reference permeation resistance value is reached, the coke arithmetic with root layer thickness (Lc) according to mixing ratio (Cm) the ratio (LC/Dc) of the average coke particle size (Dc) is the graph.

Figure 6 shows the minimum coke in the furnace core in a real blast furnace. layer thickness (Lcmin) and arithmetic mean coke particle size The ratio between (Dc) (Lcmins/Dc) and the average coke in the furnace core is a diagram showing the relationship between the layer thickness (Lcm).

Figure 7 is a diagram showing the raw material loading situation in a blast furnace. sematic diagram.

DETAILED RECIPE Below, one of the structures described in the invention is described in detail. is being done.

First, the ore with blast furnace coke of the blast furnace raw material a coke layer and an ore layer without mixing the material minimum coke in the oven core arithmetic mean coke particle size with layer thickness a problem that leads to the discovery of the need to adjust the ratio appropriately. experiment (Experiment 1) is described.

Figure 1 is a seinatic showing a device used in this experiment. is the diagram. In Figure 13, a sample heating oven (1) the filled container (2) and a heater (3). sample filled container (2) an ore with a coke layer (4) in laminated form A sample consisting of layer (5) is filled with the filled layer (6).

The temperature of the sample filled layer (6) can be controlled by the heater (3).

A gas heating oven (7) also includes a heater (8). Device, In addition, a gas mixer (9), a gas recirculation pipe (10), a pressure indicator (1 1), a heat pair (12), a pressure plate (13), a base (14), a tie rod (15) made of graphite or metal and a load includes means (16). Here, a weight is used as the load means (16).

The weight (16) is applied to the sample filled layer (6), simulating that in the blast furnace. applies a load.

The main feature of this Meter is the sample as shown in the drawing. the heating oven (1) and the gas heating oven (7) in parallel. is the placement. With parallel arrangement, heated in gas heating oven (7) the gas enters the sample heating furnace (l) laterally and the sample filled horizontally through the sample-filled layer (6) in the container (2). mite. Thus, since the sticky zone of the blast furnace] gas flow can be created.

In fact, on the measuring device, the weight (16), tie rod (15) and pressure to the sample-filled layer through the plate (13), depending on the operating conditions. base (14) so that a predetermined load can be applied according to is placed on top of it. With the above-mentioned horizontal gas flow This reflects the layer structure in the sticky zone of the blast furnace. allows the evaluation of permeability resistance.

In the experiment, the layer thicknesses of the coke layer and the ore layer permeability resistance of the adhesive zone when changing this device measured using. Table 1 shows the experimental conditions.

If the thickness of the coke layer is changed, the unit volume gas flow rate to keep the initial gas circulation rate constant per head it also changes. In fact, the thickness of each layer is independent of location. adjusted to be almost uniform.

Gas flow rate Coke layer Ore layer Coke layer thickness (N L/min) thickness (mm) thickness (mm) arithmetic mean coke particle size ratio 100 40 60 4 50 20 30 2 10 15 1 Figure 2, arithmetic mean coke particle thickness with coke layer thickness permeability resistance at 1400°C, according to the ratio of its size A graph showing the result of the measurement. coke of Lc (mm) layer thickness and arithmetic mean coke particle of Dc (mm) Let's assume it's big. 1400°C, high during operation Note that the sticky zone in the oven has a typical temperature. should be done.

Figure 2, arithmetic mean coke particle thickness with coke layer thickness permeability when ratio of magnitude (LC/Dc) is less than 2” indicates a sharp increase in resistance.

Arithmetic mean coke particle thickness with coke layer thickness permeability when the ratio of magnitude (LC/Dc) is less than 2° The reason for the sharp increase in resistance is as follows: It is considered by us to be.

In the sticky region, as shown in Figures 3A and 3B, the coke thinner coke layer (4) compared to the case where the coke layer (4) is thick. smelted ore layer (2la) per unit thickness, where The number of interfaces with which the coke layer (4) comes into contact with each other increases.

Since the smelted ore enters the coke layer at each interface, the coke to the coke layer of the smelted ore when the layer is thin. the relative inlet thickness increases. This means that the gas flows easily through the coke layer. This leads to an increase in the permeability resistance by reducing the fraction. In Figure 3, the reference mark “Zlb” is a smelted ore entering the coke layer. layer.

In particular, the arithmetic mean coke particle thickness with the coke layer thickness where the ratio of the size of the coke is less than 2° its thickness is less than the thickness of two coke particles and only one coke particle can be found in a part of it. Such a coke particle is covered with molten ore from above and below, and its As a result, the gas flow to this side is blocked.

This is the arithmetic mean of the coke layer thickness and the coke particle size. When the size ratio is less than 29, the permeability will increase sharply. It is thought to be the reason for the increase.

On the basis of the above-mentioned experimental result, the invention is ore material with high furnace coke as raw material as a coke layer and an ore layer without mixing coke loaded in the blast furnace per charge When the layer reaches the oven core, the minimum coke in the oven core The ratio of layer thickness to arithmetic mean coke particle size load in a way that satisfies the relation in Formula 1 below. performs: Lcmjn/ DC 22 (1) Here, Lcm. coke loaded in the blast furnace per charge in the furnace core The minimum layer thickness of the layer (mm) and the coke arithmetic is the average coke particle size (mm).

Arithmetic with minimum coke layer thickness in the furnace core upper limit of average coke particle size ratio 'Especially Although not limited, it measures the average root layer thickness. the upper limit is preferably 4° to minimize

Arithmetic with minimum coke layer thickness in the furnace core average coke particle size ratio in Formula 1 above intermittently, the blast furnace raw material with coke and ore conventionally, if the material is loaded without mixing it is possible to lower it further below the accepted lower limit. Detail Typically, the average root layer thickness may be 190 mm or less.

Here, with the minimum coke layer thickness in the furnace core 2 or more of the arithmetic mean coke particle size ratio The average coke layer in the oven core should be A realistic lower limit for thickness is approximately 180 mm.

Arithmetic mean coke particle size 'Specially limited Although not the arithmetic mean coke particle size preferably in the range of 20 mm to 60 mm.

The arithmetic mean coke particle size mentioned here is predetermined amount of randomly extracted coke decreasing passed through sieve meshes of order of size, in each sieve. by finding the residual coke mass product and the sieve mesh size and the calculated total product to the total coke mass subjected to sieving calculated by dividing.

In detail, the arithmetic mean coke particle size D (mm), total mass of coke subjected to sieving M (kg), i. sieve eye of the sieve size (1, (m), mass of coke remaining in the 1st sieve (kg) and number of sieves n The arithmetic mean coke particle size (D) is denoted by can be expressed by the following formula: Below is a portion of the blast furnace raw material with coke in the blast furnace. furnace in case of ore material mixed loading arithmetic mean with minimum root layer thickness in the core proper adjustment of the coke particle size ratio An experiment (Experiment 2) that leads to the discovery of the need is described.

The coke mix ratio in the mixed layer and the thickness of the coke layer the relationship between the coke mix ratio in the mixed layer and the furnace of the coke layer loaded in the blast furnace per charge in the core gas of the adhesive region of the relationship between the average thickness Description of how we discovered that you control the permeability is being done.

The coke mix ratio of cm (kg/t) and charge Lcm (mm) in the oven core average thickness of the coke layer loaded in the blast furnace per head Let's take it as. The coke mix ratio mentioned here (Ckar.) (kg/t) is the amount of coke in the mixed layer when 1 t of hot metal is produced (kg). The same device as in Figure 1 was used in this experiment.

In the experiment, the coke layer and the ore material are mixed with the coke. The mixed layer was created and the above-mentioned device was The permeability resistance of the adhesive region was measured using Root mix rate 0 kg/t (no ore material and root mix), 80 kg/t, Adjusted to 160 kg/t and 230 kg/t° and with coke layer thickness arithmetic mean coke particle size ratio per coke mix rate has been changed. Lc (mm) is the root layer thickness and Dc (mm) is accepted as the arithmetic mean coke particle size. let's. The thickness of each layer, regardless of location set almost as a uniform.

In the experiment, the amount of coke required to produce 1 t of hot metal, oil coke oraiii it is set to a fixed value (320 kg/t). In any case, arithmetic Coke with an average coke particle size of 10 mm was used. Root If the thickness of the layer is changed, per unit volume To keep the initial gas circulation rate constant, the gas flow rate is also has been changed.

Figure 4, the arithmetic mean coke particle thickness (LC) of the coke layer according to the ratio of size (Dc) (LC/Dc), each coke mix showing the result of permeability measurement at 1400°C is a graph.

Figure 4 shows the root layer thickness (Lc) at each coke mix ratio. arithmetic mean coke particle size (Dc) ratio (LC/Dc) decreases, it indicates that the permeability resistance increases.

Especially in the case where the ore material is not mixed with the coke. (mixing ratio 0 kg/t), Root layer thickness as in Experiment 1 The ratio of (LC) to the arithmetic mean coke particle size (Dc) (LC/Dc) When already less, the permeability resistance increases sharply.

Therefore, in the case where the ore material and coke are not mixed, the coke layer thickness (LC) and arithmetic mean coke particle When the size (Dc) ratio (LC/Dc) is 2, each coke mix While reaching this permeability resistance (approximately 22 kPa/m) Lc/Dc value has been determined. Figure 5, by coke mix ratio (Cm.) is a graph of the assigned Lc/Dc°.

Figure 5, when the reference permeation resistance value is reached, the coke Arithinetic with root layer thickness (LC) according to mixing ratio (Ckar.) linearly to the mean coke particle size (DC) ratio (LC/Dc) indicates that it can be approached. From this point of view, the following Formula The coke layer according to the coke mix ratio (Cm.) as indicated by “2a” arithmetic mean root particle size (Dc) ratio with thickness (LC) It can be understood that the desired permeability is achieved by limiting (LC/Dc): Lc/Dc 2-0.0063 Ckar,+ 2 (2a) However, in the real blast furnace, the coke layer is heated with the same charge. Even when created, the layer thickness varies depending on the column.

Accordingly, to ensure sufficient permeability in a real blast furnace, above the minimum thickness of the coke layer in the furnace core. It is important that it satisfies the relation in formula 2a. Oven Lomin_ (mm) Let's consider it as the thickness of the ininiinum root layer in the core. This In this case, the following formula 2 can be expressed: The ore of the blast furnace raw material with coke for a person in the blast furnace If the material is loaded with mixing, the thickness of the coke layer when the arithmetic mean coke particle size ratio is less than 2° permeability as long as Formula 2 above is met. The reason is considered by us as follows. Your mixed scent its hardening effect prevents the softened ore layer from shrinking and this reduces the penetration of molten slag into the ore layer and thus increasing the permeability.

With the minimum coke layer thickness (Lcmm) in the furnace core The relationship between the arithmetic mean root particle size (Dc) average coke in the actual blast furnace core in terms of When adjusting the layer thickness (Lcorts), Lcort. There is a correlation between Lcmin/Dc and This link is below The formula can be expressed by 3a°: From Formulas 2 and 3a above, high per charge per charge in the oven core The coke mix ratio (Ckar.) of the coke layer loaded in the kiln and the average The following relation formula (Formula) for the root layer thickness (Leon.) 3) get: Based on the above-mentioned experimental result, the blast furnace raw ore material with a high furnace part coke minimum coke in the oven core if loaded with stirring The ratio of layer thickness to arithmetic mean coke particle size The average in the furnace core with the appropriate ratio and coke mix ratio for the appropriate relation between the thickness of the coke layer is determined by us. has been discovered.

In this case too, in order to reduce the amount of coke, the upper limit of the average root layer thickness (Lcm) is 190 mm.

The coke mix ratio for mixing with the ore material is preferably 80 kg/t or more. Coke for mixing with ore inalzeine the upper limit of the mixing ratio is approximately 230 kg/t°.

Below is the raw material loading method described according to Figure 7 An example of the application of a real rotary flute blast furnace is described.

In Figure 7, the reference mark (22) is a blast furnace, (22a) a furnace neck, (22b) a kiln core, (23a) to (23c) kiln top bins, (23d) a central root layer, (23e) a peripheral root layer, (23f) a nerve area, (24) a collection hopper, (25) a hubless loading device, (26) is a rotary chute and (27) is a high-pressure tube vent.

In this example, only coke is stored in the kiln top bin 23a and in silo 230 only ore material is stored.

Rotary groove in the case where coke and ore material are not mixed high furnace raw material loading, coke returns with ore material It is carried out by loading the trough (26) alternately. In the oven, coke layer (4) and ore layer (5) alternating in laminated form is created as

As a specific example of the coke layer loading procedure, the sequential The following method using the eine technique can be used. First As a result, the rotary chute (26) has a high raw material loading destination. the oven wall (22) is adjusted to the inner circumferential region, the oven interior to form the peripheral root layer 23e in the peripheral region of the wall. coke is loaded only from the furnace top silo (23a), which stores coke. More Then, the rotary chute (26) has a high raw material loading destination. in the center zone of the oven, adjusted to the central zone of the oven. from the furnace top silo (23a) to form the central coke layer (23d). coke is loaded.

Thus, the central coke layer 23d and the peripheral layer of the coke layer (4) If formed from the coke layer 23e, typically coke layer (4) with the central root layer (23d) as shown in Figure 7° minimum in the border region (23f) between the peripheral root layer (23e) It has layer thickness (tmm.).

Oven throat (22a), through which raw material is loaded, and inside The inner diameters of the oven core (22b) where the adhesive zone is formed are different. The thickness of the coke layer in the kiln throat (22a) is typical. As a result, the thickness of the coke layer in the furnace core (22b) is approximately 2.2 times.

Accordingly, the target average coke layer in the furnace core kaliiiligiiiidaii amount of coke loaded in the blast furnace per charge determined and the central coke layer and the peripheral coke layer the thickness of the root layer in the border region between layer thickness, the target coke layer thickness in the furnace core By adjusting the amount of load to be approximately 2.2 times, the oven The target root layer thickness in the core can be realized.

Mixed layer of some coke and ore material blast furnace raw material with rotary flute when mixed loading, for example only from the oven top silo (23a) alternately by loading coke and simultaneously removing the coke and oven top bin from the oven top silo (23a). This is accomplished by loading ore from the silo (23c). Bake, coke layer (4) by mixing the coke and ore material. The composite layer (5) formed is alternately in laminated form. is created.

As a specific example of the coke layer loading procedure, the sequential The following method using the bending technique can be used. First As a result, the rotary chute (26) has a high raw material loading destination. the oven wall (22) is adjusted to the inner circumferential region, the oven interior to form the peripheral root layer 23e in the peripheral region of the wall. coke is loaded only from the furnace top silo (23a), which stores coke. More Then, the rotary chute (26) has a high raw material loading destination. in the center zone of the oven, adjusted to the central zone of the oven. from the furnace top silo (23a) to form the central coke layer (23d). coke is loaded.

If the coke layer is loaded in this way, the coke layer (4) As shown in Figure 7, the central root layer (23d) and the peripheral The minimum layer in the nerve region (23f) between the root layer (23e) It has thickness (tmm.).

Oven throat (22a), through which raw material is loaded, and inside The inner diameters of the oven core (22b) where the adhesive zone is formed are different. thickness of the coke layer in the kiln throat (22a). It is approximately 2.2 times the thickness of the root layer in the core (22b).

Accordingly, the coke mix for mixing with the ore material the target average coke layer thickness in the furnace core by adjusting and the thickness of the coke layer in the oven throat, the oven approximately 2.2 of the average root layer thickness set in the core By adjusting the coke loading amount to be solid, the raw material described material loading method is applicable to real blast furnace. EXAMPLES First Example This example is based on blast furnace feedstock with blast furnace coke and ore. a coke layer and an ore layer without mixing the material It is related to the loading status.

As shown in Figure 7, in a real rotary flute blast furnace, the same minimum coke layer in the furnace core at the pig iron draw ratio arithmetic mean root particle size ratio with thickness changed and the results of the processes in the relevant cases are compared.

Table 2 shows the results.

Here, the pig iron draw rate is the blast furnace draw rate per day. (t/day) divided by the kiln volume (m3). reducing agent ratio, coke ratio and pulverized coal ratio, when producing 1 t hot metal amount of reducing agent used, amount of coke and pulverized is the amount of coal (kg/t).

Traditional Comparative Example 1 Average coke in the oven core 233 117 171 layer thickness (Lcm) (mm) Ortalaina in the oven core 430 210 321 Minimum coke in the oven core 3.0 1.5 2.2 arithmetic with layer thickness average coke particle ratio of magnitude (Lcmm/Dc) Average coke in the furnace throat 513 257 376 layer thickness (mm) Average 946 461 707 in the oven throat Pig iron shrinkage 2.0 2.0 2.0 Reducing agent rate (kg/t) 510 508 505 Coke rate (kg/t) 362 372 355 Pulverized coal rate (kg/t) 148 136 150 Gas usage rate (%) 48,] 48.5 48.6 Filled sheet pressure drop 21.8 28.5 21.9 (kPa/(Nm3/min)) As shown in the table, in Example ls, the pressure drop is conventional is almost equal to that in the example, and therefore in the permeation resistance did not increase. Moreover, in Example 1, the average root layer thickness and at the same time, the ore layer thickness is compared to the traditional 'sample'. significantly reduced and with a lower reducing agent ratio increased reduction efficiency was obtained.

On the other hand, in Comparative Example 1, arithmetic mean coke particle with minimum coke layer thickness the ratio of its magnitude is less than 2°. Accordingly, the pressure drop higher than that of the conventional sample and therefore the permeability increased in resistance.

Second Example This example is a blast furnace coke layer of the blast furnace feedstock. and a portion of coke formed by mixing the ore material. loading of coke and ore material into mixed layer relates to the situation.

As shown in Figure 73, in a real rotary flute blast furnace, the same coke for mixing with ore material at pig iron draw ratio Average coke layer thickness in the furnace core by mixing ratio changed and the results of the processes in the relevant cases are compared.

Table 3 shows the results.

Here, the pig iron draw rate is the blast furnace draw rate per day. (t/day) divided by the kiln volume (m3). Reducing agent ratio, coke ratio and pulverized coal ratio, when producing 1 t hot metal amount of reducing agent, amount of coke and pulverized is the amount of coal (kg/t). Example 2 Example 3 Comparative Minimum coke in oven core 55 1 10 47 layer thickness (Lcmin.) Arithmetic mean coke particle 50 50 50 size (Dc) (mm) Minimum coke in the oven core 1.1 2.2 0.9 arithmetic with layer thickness average coke particle Average coke in the furnace throat 297 418 279 layer thickness (mm) Average coke in the oven core 135 190 127 layer thickness (Leon.) (mm) Pig iron drawing rate (t/m3/day) 2.0 2.0 2.0 Reducing agent rate (kg/t) 505 506 514 Coke rate (kg/t) 357 358 366 Coke mix ratio (Ckar) (kg/t) 160 160 160 Pulverized coal rate (kg/t) 148 148 148 Gas usage rate (%) 48.6 48.3 47.5 Filled sheet pressure drop 21.7 21.2 23.8 (kPa/(Nm3/min)) As shown in the table, in Examples 2 and 3, the pressure drop is low and sufficient permeability is achieved. In addition, the coke ratio has been reduced and this contributes to the use of a lower reducing agent has been found.

On the other hand, in Comparative Example 2, the average in the oven core The root layer thickness is below the lower limit defined in Formula 1 above. is below. Accordingly, the pressure drop is higher and the permeability has decreased. Besides, in Comparative Example 2, the permeability coke ratio increased due to the decrease. Third Example The coke mix ratio was changed according to the conditions in Table 4 and the relevant The results of the operation in the cases were compared. Table 4 results shows. Conditions other than those shown in Table 4 Example It is the same as the conditions at 2°.

Coke mix ratio (Cm.) (kg/t) 60 80 100 Average coke in the oven core 180 180 180 layer thickness (Leon.) (mm) Formula Pin right side 161 155 149 Reducing agent rate (kg/t) 510 508 507 Coke rate (kg/t) 362 360 359 Pulverized coal rate (kg/t) 148 148 148 Gas usage rate (%) 48.1 48.2 48.3 Filled sheet pressure drop 21.8 21.7 21.6 (kPa/(Nin3/min)) As shown in the table, a coke mix ratio of 80 kg/t° is used. Pressure drop in Example 5 and 6 A coke mix ratio of 60 kg/t it was lower than in Example 4 used and a better permeability is achieved. In addition, the proportion of coke has been reduced, which contributed to the use of a lower reducing agent.

Claims (1)

REQUESTS 1. A blast furnace (22) is loaded with ore material and coke-containing blast furnace feedstock (22) using a rotary chute (22) and blast furnace feedstock (22) is loaded with coke and ore material The blast furnace raw material is loaded as a coke layer (4) and an ore layer (5) without mixing, or as a coke layer (4) and a person as a mixed layer of coke and ore material formed by mixing coke with ore material, the blast furnace raw material (22) coke When the coke layer (4) loaded in the blast furnace (22) per charge reaches the core (22b) of the blast furnace, the ratio of the minimum thickness of the coke layer (4) in the furnace core (22b) and the arithmetic mean particle size of coke is calculated by the following Formula where the range is limited to ° or if the blast furnace raw material is loaded into the blast furnace (22) by mixing a portion of coke and ore material. Lciiiiii./DC 22 (l) Lcmin/Dc 2-0.0063 Ckar_ + 2 (2) in these formulas, Ckar_”, the coke mix ratio in kg/t in the mixed layer, Lle-n, the minimum coke layer (4) loaded in the blast furnace (22) per charge per charge in the furnace core (22b) and Dc in mm, the coke A method where the arithmetic mean particle size is in mm. . In order to load raw material into a blast furnace (22) as defined in claim 1, if the blast furnace material is loaded as a coke layer (4) of the blast furnace (22) and a mixed layer of coke and ore material formed by mixing a part of coke with ore material, In the furnace core (22b) the average layer thickness of the coke layer (4) loaded in the blast furnace (22) per charge is limited to a range defined by the following Formula 3 depending on the coke mixture ratio in the mixed layer, in this formula C is the coke mixture ratio in kg/t and Lcort_7niii, a method where the coke layer (4) loaded in the blast furnace 22 per charge in the furnace core (22b) is the average layer thickness in mm. . The method for loading raw materials into a blast furnace (22) as defined in claim 2, where the coke mix ratio (Ckar.) is 80 kg/t or more.