JP2018062681A - Method of estimating mixture ratio of raw material in blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of simply estimating a mixture ratio of raw materials when the mixed raw materials are blended in a blast furnace.SOLUTION: A volume flow rate of a mixed raw material discharged from a hopper is determined (step S1). When continuously discharging the mixed raw material from the hopper, the weight of the hopper is measured (step S2). Based on the weight of the hopper measured in step S2, the mass flow rate of the mixed raw material at the predetermined time is obtained (step S3). Making the volume flow rate of the mixed raw material determined in step S1 constant, a mixture ratio of a raw material to be added to the matrix material in the mixed material is estimated based on the mass flow rate of the mixed raw material obtained in step S3 (steps S4 and S5).SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for estimating a mixing ratio of mixed raw materials when a plurality of types of raw materials are mixed and charged in a blast furnace.

  Generally, in a blast furnace in the production of pig iron, ore and coke are sequentially charged and deposited as charges from the top of the furnace, and an ore layer and a coke layer are formed in the furnace. After the ore is heated and reduced by the CO gas generated by the reaction between the hot air blown from the tuyere below the blast furnace and the coke, a part is directly reduced by the coke to form a softened cohesive zone. It becomes a droplet, that is, molten iron.

  Here, ore is a general term for iron raw materials. In blast furnace operation in Japan, for example, it is composed of 85% sintered ore, 10% lump ore, and 5% pellets. Further, various kinds of brands are mixed into this ore for various purposes. Here, this is called a mixed raw material. The mixed raw material is charged into the furnace to form an ore layer (Patent Document 1).

  The raw material added to the ore is different in density and particle size from the sintered ore which is the main component of the ore. For this reason, segregation occurs without being uniformly dispersed in the ore layer. For example, the density of the small coke to promote the reduction of the sintered ore is about 1/3 that of the ore. Therefore, when the ore and the small coke are transported to the blast furnace, they are segregated at the time of charging and discharging into the hopper in the middle of the transport. As a result, when charging the blast furnace, the charging amount is biased in a specific time zone.

  Patent Document 2 discloses a method of measuring the weight mixing degree (mixing ratio of ore and small coke) of each raw material in the mixed raw material discharged from the hopper. That is, in this method, the total weight of the mixed raw material is measured based on the output value of the load cell provided in the furnace top hopper, and further, based on the output value of the coil sensor attached to the discharge port of the furnace top hopper, By measuring the weight value of each of the sintered ore and coke, the mixing degree of the raw materials is estimated.

Japanese Patent No. 2808343 JP 2007-204791 A

  However, when the method disclosed in Patent Document 2 is used, two measuring units, a load cell and a coil sensor, are required to estimate the mixing degree of the raw materials. For this reason, equipment cost and maintenance cost are required, and estimation of the degree of mixing becomes complicated.

  The present invention has been made in view of such points, and an object of the present invention is to provide a method for easily estimating a mixing ratio of mixed raw materials when charging a blast furnace with a mixture of plural types of raw materials. .

  In order to achieve the above object, the present inventor investigated the discharge behavior of various mixed granules from the hopper, and found that the raw materials used in the blast furnace method (raw material charging method), the mixing ratio of the raw materials (compounding) In the range of the ratio, the volume flow rate of the mixed raw material discharged from the hopper was found to be almost constant regardless of the type and mixing ratio of the mixture mixed in the ore.

  The present invention has been made on the basis of such knowledge, and is a method for estimating the mixing ratio of mixed raw materials when mixing and charging a plurality of types of raw materials into a blast furnace, which is discharged from a hopper. The first step of determining the volume flow rate of the mixed raw material, the second step of measuring the weight of the hopper when the mixed raw material is continuously discharged from the hopper, and the second step. Further, based on the weight of the hopper, a third step of obtaining a mass flow rate of the mixed raw material at a predetermined time, and a volume flow rate of the mixed raw material determined in the first step are constant, and the third step And a fourth step of estimating a mixing ratio of the additive raw material added to the parent phase raw material among the mixed raw materials based on the mass flow rate of the mixed raw material obtained in the step.

  The matrix phase raw material may be sintered ore or ore.

  Moreover, the weight of the hopper in the second step may be measured using a load cell provided in the hopper.

Further, in the fourth step, the mass flow rate of the additive material and the matrix material in a predetermined time _{t W A, t, W B} , t and the following formulas (1), calculated by (2), wherein the mixing ratio M _t of added material may be estimated by the following equation (3).
_{W A, t = (ρ A} ρ B V-ρ A W t) / (ρ B -ρ A) ···· (1)
W _{B, t} = W _t −W _{A, t} (2)
M _t = W _{B, t} / W _t (3)
Where W _{A, t is} the mass flow rate of the parent phase raw material at a predetermined time t, W _{B, t is} the mass flow rate of the added raw material at the predetermined time t, W _{t is} the mass flow rate of the mixed raw material at the predetermined time t, and ρ. _A : Bulk density of parent phase raw material, ρ _B : Bulk density of additive raw material, V: Volume flow rate of mixed raw material, M _t : Mixing ratio

  In addition, when there are a plurality of additive raw materials, the fourth step includes a mass flow rate of one additive raw material having a bulk density farthest from the bulk density of the matrix raw material among the plurality of additive raw materials. A fifth step of calculating a mass flow rate of the raw material in a state where the matrix raw material and the additional raw material other than the one additional raw material among the plurality of additional raw materials are mixed, The sixth step of calculating the mass flow rate of the matrix raw material and the mass flow rate of the other additive raw materials, the fifth step and the sixth step are each performed one or more times in this order, And a seventh step of calculating a mass flow rate of the additive raw material and estimating a mixing ratio of the respective additive raw materials.

  According to the present invention, the mixing ratio of the mixed raw materials (mixing ratio of the additive raw materials) can be appropriately estimated by performing the first to fourth steps. In addition, in estimating the mixing ratio, only the weight of the hopper actually needs to be measured, and two weight measuring means, particularly a coil sensor, is not required as in the prior art. Therefore, it is possible to easily estimate the mixing ratio.

It is explanatory drawing which shows typically the outline of a structure of the raw material charging device used by this Embodiment. The simulation result of the behavior of the raw material discharged from the hopper is shown, (a) shows the change over time of the volume flow rate of the mixed raw material, (b) shows the change over time of the mass flow rate of the sintered ore, (c) Indicates the time course of the mass flow rate of the small coke. It is a flowchart which shows the example of the process of the raw material mixing ratio estimation method of the blast furnace concerning 1st Embodiment. It is a flowchart which shows the example of the process of the raw material mixing ratio estimation method of the blast furnace concerning 2nd Embodiment. About Example 1, the time-dependent change of the mass flow rate of the mixed raw material in an Example is shown. About Example 1, the time-dependent change of the mass flow rate of the small coke in an Example is shown. About Example 1, the time-dependent change of the mass flow rate of the small coke in a comparative example is shown. In Example 2, the time-dependent change of the actual value and estimated value of the mixing ratio of the small coke is shown. In Example 2, the time-dependent change of the actual value and estimated value of the mixing ratio of the meteorite is shown.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present specification and drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

<1. Raw material charging device>
First, the raw material charging apparatus used in the present embodiment will be described. FIG. 1 is an explanatory view schematically showing the outline of the configuration of a bell-less type raw material charging apparatus. The parallel hopper type raw material charging apparatus will be described below, but the present invention can be applied to other raw material charging apparatuses such as a vertical type.

  The raw material charging device 10 is a parallel hopper type raw material charging device, and charges the blast furnace 20 with the raw material. The raw material charging apparatus 10 includes a plurality of, for example, two furnace top hoppers 11 a and 11 b, a collecting chute 12, a vertical chute 13, and a turning chute 14. The furnace top hoppers 11a and 11b, the collecting chute 12, the vertical chute 13, and the turning chute 14 are arranged in this order from the upper side to the lower side.

  The furnace top hoppers 11 a and 11 b are arranged to face each other in parallel, and the discharge ports of the furnace top hoppers 11 a and 11 b are arranged eccentrically from the central axis of the vertical chute 13. Flow rate adjusting gates 15a and 15b for adjusting the flow rate of the raw material are provided at the discharge ports of the furnace top hoppers 11a and 11b. Load cells 16a and 16b for measuring the weight of the furnace top hopper 11 are provided in the furnace top hoppers 11a and 11b. In addition, the load measuring device which measures the weight of the furnace top hopper 11 is not limited to the load cell 16, Other load measuring devices can be used arbitrarily. In each furnace top hopper 11a, 11b, the raw material R for one charge is temporarily stored. While the raw material R in one furnace top hopper 11a is charged into the furnace, the raw material R is received by the other furnace top hopper 11b. By repeating this alternately, the time required for receiving and charging the raw material R is shortened.

  In addition, the raw material R of the furnace top hopper 11a is a mixed material for forming an ore layer in the blast furnace 20, for example. In this embodiment, an example in which a material in which ore that is a matrix material and a small coke that is an additive material added to the matrix material are mixed is described as the mixed material. Moreover, the raw material R of the furnace top hopper 11b is coke for forming a coke layer in the blast furnace 20, for example.

  The collecting chute 12 collects the raw material R discharged from the furnace top hoppers 11 a and 11 b and flows it to the vertical chute 13.

  The vertical chute 13 has a substantially cylindrical shape, is connected to the lower surface of the collective chute 12, and flows the raw material R discharged from the collective chute 12 to the turning chute 14.

  The turning chute 14 receives the raw material R discharged from the vertical chute 13 and charges the raw material R into the blast furnace 20 from its tip. The turning chute 14 is configured to be rotatable in the circumferential direction of the blast furnace 20 around the vertical chute 13 by a drive mechanism (not shown). Further, the turning chute 14 is configured to be tiltable (turnable) in the vertical direction around the vertical chute 13, and the rotation radius of the turning chute 14 can be arbitrarily changed.

  In the raw material charging apparatus 10, the raw material R in the furnace top hoppers 11 a and 11 b is adjusted in flow rate by the flow rate adjusting gates 15 a and 15 b and discharged to the collecting chute 12. The raw material R falls on the turning chute 14 via the collecting chute 12 and the vertical chute 13 and is charged into the blast furnace 20 from the tip of the turning chute 14.

  In the following description, the above-described furnace top hopper 11 may be simply referred to as a hopper.

<2. Behavior of mixed raw material from hopper>
The blast furnace raw material mixing ratio estimation method according to the present invention is based on the new knowledge that the volume flow rate of the mixed raw material discharged from the hopper can be considered constant. In obtaining such knowledge, the present inventor conducted the following simulation to investigate the behavior of the raw material from the hopper.

  In the simulation, a discrete element method (DEM: Discrete Element Method) is used under the condition that two kinds of raw materials having different densities, that is, sintered ore and small coke are mixed in a hopper and the mixed raw material is discharged from the hopper. Used. The calculation conditions for this simulation were as follows: the average particle diameter of the sintered ore was 25 mm, the weight of the sintered ore was 28 ton, the average particle diameter of the small coke was 35 mm, and the weight of the small coke was 1.8 ton.

  The simulation result is shown in FIG. FIG. 2 (a) shows the change over time of the volume flow rate of the mixed raw material discharged from the hopper, and FIG. 2 (b) shows the change over time of the mass flow rate of the sintered ore discharged from the hopper. 2 (c) shows the change with time of the mass flow rate of the small coke discharged from the hopper. 2A to 2C, the horizontal axis indicates the elapsed time, and the material discharge start time from the hopper is set to “0”, and the material discharge completion time is set to “1”.

  Referring to FIG. 2, it was confirmed that the volume flow rate of the mixed raw material was almost constant over time, and new knowledge was obtained.

  In addition, P. of Shigeo Miwa "Powder Fluid Engineering (1972)". In 212-213, it is described that the mass flow rate W of the powder defined by the following formula (4) (hereinafter, described by replacing with a mixed raw material) is constant.

However, W: Mass flow rate of mixed raw material, ρ: Bulk density of mixed raw material, D _p : Particle diameter of mixed raw material, f: Friction coefficient, φ: Opening angle of hopper, D ₀ : Diameter of outlet of hopper

Here, the volume flow rate V of the mixed raw material is represented by the following formula (5). Then, it can be said that the new knowledge that the volume flow rate V of the mixed raw material described above is constant, in other words, the bulk density ρ of the mixed raw material is constant. That is, even if a plurality of types of raw materials are flowing in the hopper, the bulk density ρ of the mixed raw materials when discharged from the hopper can be considered to be constant.
V = W / ρ (5)
However, V: Volume flow rate of mixed raw material, W: Mass flow rate of mixed raw material, ρ: Bulk density of mixed raw material

  On the other hand, conventionally, the mass flow rate W of the raw material was considered to be constant, but when mixing plural types of raw materials as in the present invention, for example, the bulk density ρ of the mixed raw material can be treated as constant. It was not supposed. Therefore, it is a very new finding that the volume flow rate V of the mixed raw material is constant.

  Even if it turns, the said Formula (4) will be the type | formula which assumed the single raw material, and the mixed raw material with which multiple types of raw material was mixed was not assumed. From this viewpoint, it can be said that the knowledge that the volume flow rate V of the mixed raw material is constant is new.

<3. Blast Furnace Raw Material Mixing Ratio Estimating Method According to First Embodiment>
Next, the raw material mixing ratio estimation method for the blast furnace according to the first embodiment, which is made based on the above-described knowledge, will be described. FIG. 3 is a flowchart showing an example of the steps of the blast furnace raw material mixing ratio estimation method.

(Step S1)
First, the volume flow rate of the mixed raw material discharged from the hopper is determined. The volume flow rate of this mixed raw material can be determined by various methods, for example, it may be determined using actual measurement values, may be determined using a theoretical formula, or may be estimated using the discharge time of the mixed raw material. May be.

When the theoretical formula is used, for example, the volume flow rate V of the mixed raw material is determined using the following formula (6). This formula (6) is derived by dividing the formula (4) by the bulk density ρ because the bulk density ρ of the mixed raw material can be regarded as constant in the formula (4) as described above. The particle diameter D _p of the mixed material is sampled before turning the mixed raw material of the batch hopper, the particle size can be determined by measuring a sieve. The friction coefficient f can be estimated by measuring the angle of repose of the mixed raw material.

However, W: Mass flow rate of mixed raw material, ρ: Bulk density of mixed raw material, D _p : Particle diameter of mixed raw material, f: Friction coefficient, φ: Opening angle of hopper, D ₀ : Diameter of outlet of hopper

Moreover, when using the discharge time of a mixed raw material, the volumetric flow rate V of a mixed raw material is determined using Formula (7), for example. Specifically, the weight Q of the mixed raw material charged into the hopper and the time θ required for discharging the total amount are obtained, and the volume flow rate V of the mixed raw material is determined from the equation (7). As long as the gate opening degree is the same, the discharge time θ may be the mixed material discharge time in the previous batch instead of the batch discharge time.
V = Q / ρθ (7)

(Step S2)
Next, the weight Q _h of the hopper containing the mixed raw material as the contents is continuously measured by a load cell provided in the hopper.

(Step S3)
Next, the change amount dQ _h / dt of the hopper weight Q _{h at} a predetermined time t is obtained based on the hopper weight Q _h measured in step S2. This dQ _h / dt is defined as a mass flow rate W _t of the mixed raw material at a predetermined time t.

(Step S4)
At this time, the following relational expressions (8) and (9) are established. The subscripts A and B in the formula are particle brands, A indicates an ore that is a parent phase raw material, and B indicates a small coke that is an additive raw material.
W _t = W _{A, t} + W _{B, t} (8)
V = W _{A, t} / ρ _A + W _{B, t} / ρ _B (9)
Where W _t : mass flow rate of the mixed raw material at a predetermined time t, W _{A, t} : mass flow rate of the ore at a predetermined time t, W _{B, t} : mass flow rate of the small coke at the predetermined time t, V: Volume flow rate of mixed raw material, ρ _A : Bulk density of ore, ρ _B : Bulk density of small coke

The following formulas (1) and (2) are obtained by solving the above formulas (8) and (9). The volume flow rate V of the mixed raw material determined in step S1 is constant, and the mass flow rate W _{A, t of the} ore and the mass of the small coke are based on the mass flow rate W _t of the mixed raw material calculated in step S3. The flow rate WB _{, t} is calculated.
_{W A, t = (ρ A} ρ B V-ρ A W t) / (ρ B -ρ A) ···· (1)
W _{B, t} = W _t −W _{A, t} (2)

(Step S5)
Next, based on the mass flow rate W _t of the mixed raw material calculated in step S3 and the mass flow rate W _{B, t of} the small coke calculated in step S4, the following formula (3) is used. The mixing ratio M _t of the added raw material is estimated.
M _t = W _{B, t} / W _t (3)

  According to the above embodiment, the mixture ratio of the small coke in a mixing raw material can be estimated appropriately by performing step S1-S5. In addition, in estimating the mixing ratio, the only thing that actually needs to be measured is the weight of the hopper by the load cell, and two weight measuring means, particularly a coil sensor, is not required as in the prior art. Therefore, it is possible to easily estimate the mixing ratio.

  And the mixing ratio estimated appropriately in this way can be utilized as follows in the raw material charging step of the blast furnace.

  For example, the raw material charging device is provided with a segregation adjusting device that adjusts the segregation of the mixed raw material when the mixed raw material is charged into the furnace top hopper. Therefore, the segregation adjusting device can be controlled so that the change with time of the mixing ratio estimated by the method of the present invention becomes uniform.

  Further, for example, when the mixed raw material is charged into the blast furnace based on the mixing ratio estimated by the method of the present invention, the angle of the turning chute is appropriately controlled. If it does so, the mixing raw material with a high mixing ratio of a small coke can be charged in the position where the consumption of the small coke is large in the furnace radial direction.

  In addition, although the above embodiment demonstrated the case where a parent phase raw material was an ore and an additional raw material was a small lump coke, a parent phase raw material and an additional raw material are not limited to this. This embodiment can be applied to a mixture of sintered ore, massive ore, and pellets composed of various ratios as a matrix raw material. In addition, this embodiment uses blast furnace raw materials such as ferro-coke, carbon-containing agglomerated minerals, reduced iron powder, scrap ore, and auxiliary raw materials such as limestone, serpentinite, peridotite, and meteorite as additive raw materials. It can also be applied to cases. That is, if the additive raw material particles have a density difference from the parent phase raw material particles, the mixing ratio of the additive raw materials can be estimated by applying this embodiment.

<4. Raw Material Mixing Ratio Estimating Method According to Second Embodiment>
Next, the raw material mixture ratio estimation method when there are two or more types of additive raw materials according to the second embodiment will be described. FIG. 4 is a flowchart showing an example of the steps of the blast furnace raw material mixture ratio estimation method. In this embodiment, matrix raw material A (ore), additive raw material B (small coke), and additive raw material C (meteorite) are used, and the bulk density of each of raw materials A, B, and C is ρ _A > ρ _C > ρ _B And Note that the additive material C does not have to be meteorite.

(Steps S1 to S3)
Since Steps S1 to S3 in the second embodiment are the same as Steps S1 to S3 in the first embodiment described above, description thereof will be omitted.

(Step S4 ′)
The state in which the matrix raw material A and the additive raw material C having a close bulk density are mixed is considered as one mixed particle, and the above formulas (8) and (9) are defined as the following formulas (8 ′) and (9 ′).
W _t = W _{AC, t} + W _{B, t} (8 ′)
V = W _{AC, t} / ρ _AC + W _{B, t} / ρ _B (9 ′)
Where, W _{AC, t} : mass flow rate in a state where ore and meteorite are mixed at a predetermined time t, ρ _AC : bulk density in a state where ore and meteorite are mixed

The following formulas (1 ′) and (2 ′) are obtained by solving the above formulas (8 ′) and (9 ′). Then, the volume flow rate V of the mixed raw material determined in step S1 is made constant, and the mass flow rate W _{AC, t of the} ore and meteorite and the small block coke based on the mass flow rate W _t of the mixed raw material calculated in step S3. The mass flow rate WB _{, t of} is calculated.
W _{AC, t} = (ρ _AC ρ _B V−ρ _AC W _t ) / (ρ _B −ρ _AC ) (1 ′)
W _{B, t} = W _t −W _{AC, t} ... (2 ′)

(Step S5 ′)
Next, using the mass flow rate W _{B, t} of the small coke calculated in step S4 ′, the volume flow rate V _{AC, t} of ore and meteorite at a predetermined time t is calculated using the following equation (10). To do.
V _{AC, t} = V−W _{B, t} / ρ _B (10)

(Step S6 ′)
Next, the mass flow rates of the matrix raw material A and the additive raw material C are separated from _{WAC, t} , respectively, and obtained. Expressions (8 ′) and (9 ′) are changed to Expressions (8 ″) and (9 ″).
W _{AC, t} = W _{A, t} + W _{C, t} (8 ″)
V _{AC, t} = W _{A, t} / ρ _A + W _{C, t} / ρ _C (9 ″)
Where W _{C, t} : Mass flow rate of meteorite at a predetermined time t

By solving the above formulas (8 ″) and (9 ″), the following formulas (1 ″) and (2 ″) are obtained. From these formulas, the mass flow rate WA _{, t of the} ore and the meteorite The mass flow rate W _{C, t of} is determined.
_{W A, t = (ρ A} ρ C V AC, t -ρ A W AC, t) / (ρ C -ρ A) ···· (1 '')
W _{C, t} = W _{AC, t} −W _{A, t} (2 ″)

(Step S7 ')
Next, the mass flow rate W _t of the mixed raw material calculated in step S3, the mass flow rate W _{B, t of} the small coke calculated in step S4 ′, and the mass flow rate W _{C of} meteorite calculated in step S6 ′. _{, t} , the following formulas (3 ′) and (3 ″) are used to estimate the mixing ratios M _{B, t} and M _{C, t} of the added raw materials B and C in the mixed raw materials.
M _{B, t} = W _{B, t} / W _t (3 ′)
M _{C, t} = W _{C, t} / W _t (3 ″)

  According to the above embodiment, by performing Steps S1 to S7 ', it is possible to appropriately estimate the mixing ratio of the additive raw material in the mixed raw materials of a plurality of brands.

  In the above embodiment, the case where the matrix raw material A is an ore, the additive raw material B is a small coke, and the additive raw material C is a meteorite has been described, but the matrix raw material and the additive raw material are not limited thereto. . This embodiment can be applied to a mixture of sintered ore, massive ore, and pellets composed of various ratios as a matrix raw material. In addition, this embodiment is used in the case of using blast furnace raw materials such as ferro-coke, coal-containing agglomerated mineral, reduced iron powder, scrap ore, and auxiliary raw materials such as limestone, serpentinite and peridotite as additive raw materials. Can also be applied. That is, if the additive raw material particles have a density difference from the parent phase raw material particles, the mixing ratio of the additive raw materials can be estimated by applying this embodiment. What is necessary is just to obtain | require mass flow rate in an order from a thing with a large density difference with a parent phase raw material.

For example, when the additive raw materials are three types of B, C, and D and the bulk density is ρ _A > ρ _D > ρ _C > ρ _B , among the additive raw materials B, C, and D, the parent phase raw material A and Considering the state in which the additive materials C and D having a close bulk density are mixed as one mixed particle, steps S4 ′ to S6 ′ are performed, and the mass flow rate of the additive material B and the additive materials C and D are mixed. Calculate mass flow rate. Thereafter, among the added raw materials C and D, the mixed raw material A and the added raw material D having a bulk density close to each other are considered as one mixed particle, and steps S4 ′ to S6 ′ are further performed. The flow rate and the mass flow rate of the additive raw material D are calculated. In step S7 ′, the mixing ratio of the additive raw materials B, C and D in the mixed raw material is estimated.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the idea described in the claims, and these naturally belong to the technical scope of the present invention. It is understood.

  Although the case where the present invention is applied to a furnace top hopper has been described in the above embodiment, the present invention can be applied to all other hoppers (for example, a surge hopper).

Hereinafter, effects of the present invention (first embodiment) will be described based on examples and comparative examples. Specifically, the mass flow rate WB _{, t} of the small coke calculated by the equation (2), which is the basis of the mixing ratio M _t of the added raw material estimated by the equation (3) described above, is verified. .

In the embodiment, actual furnace at (blast furnace), and transporting the ore 80ton and small lump coke 1.9Ton, the weight Q _h of furnace top hopper during mixing raw materials discharged was continuously measured by the load cell. Then, the weight change amount dQ _h / dt of the furnace top hopper at a predetermined time, that is, the mass flow rate W _t of the mixed raw material at the predetermined time was obtained. The mass flow rate W _t of the raw material mixture obtained in this way is shown in FIG.

Moreover, in the Example, the volume flow rate V of the mixed raw material discharged | emitted from a furnace top hopper was calculated | required using Formula (6) mentioned above. In equation (6), the particle diameter _{D p} of the mixed raw material and 18 mm, the friction coefficient f is 0.4, and 45 degrees opening angle φ of the furnace top hopper, the diameter _{D 0} of the outlet of the hopper was 655mm . Then, the volume flow rate V of the mixed raw material was found to be 0.71 m ³ / s.

Then, based on the volume flow rate V of the mass flow rate W _t and mixed raw material mixture of these raw materials, the mass flow rate W _B of the small lump coke using equation (2) _above, was calculated _t. In this case, the bulk density [rho _A ore and 1.8ton / ^{m 3,} the bulk density [rho _B small lump coke was 0.5 ton / ^{m 3.} As a result, the mass flow rate WB _{, t of} the small coke was determined as shown in FIG.

  On the other hand, in the comparative example, it experimented using the test apparatus of 1/5 scale which becomes a similar shape of a real furnace (blast furnace). The mixed raw material discharged from the furnace top hopper was collected by a predetermined sampling device, and the weight of the small coke in each time zone was measured. As a result, the mass flow rate of the small coke was determined as shown in FIG.

  Comparing FIG. 6 of the example and FIG. 7 of the comparative example, the tendency of the mass flow rate of the small coke to change with time is in a very good correspondence. Therefore, it was found that the mass flow rate of the small coke calculated in the present invention is extremely high in accuracy. And it turned out that the accuracy of the mixing ratio of the additive raw material estimated based on the mass flow rate of the small coke is also extremely high.

The effects of the present invention (second embodiment) will be described below. Specifically, mass flow rates WB _{, t} and WC _, when a plurality of types of additive raw material B (small coke) and additive raw material C (meteorite) are mixed with matrix raw material A (ore) _. The verification of _t (mixing ratio M _{B, t} and M _{C, t} ) was performed using the discrete element method (DEM). In this verification, the average particle diameter of sintered ore is 25 mm, the weight of sintered ore is 28 ton, the average particle diameter of small coke is 35 mm, the weight of small coke is 1.8 ton, and the average particle diameter of meteorite is The weight of 30 mm and the meteorite was 3.0 ton. All the mixed particles were charged into the hopper, then discharged from the hopper, and the brand and weight of the discharged particles were investigated.

FIGS. 8 and 9 show the results (actual values) obtained by simulating the change over time in the mixing ratio of the small coke and the meteorite by DEM and the estimated values based on the equations (3 ′) and (3 ″). In this case, the bulk density [rho _A sinter and 1.8ton / ^{m 3,} the bulk density [rho _B of 0.5 ton / ^{m 3} of a small lump coke, and 1.15ton / ^{m 3} the bulk density [rho _C of Keiseki did. Further, the bulk density [rho _AC when sintered ore and Keiseki is in admixture was 1.7ton / ^{m 3.}

  8 and 9 confirm that the tendency of the change in the mixing ratio of the small coke and the meteorite with the actual values simulated by the DEM and the estimated values based on the equations (3 ′) and (3 ″) are very high. Good correspondence. Therefore, even when a plurality of brands calculated in the present invention are used as additive raw materials, it has been found that the accuracy of the mass flow rate of the additive raw materials is extremely high.

  The present invention is useful for estimating the mixing ratio of mixed raw materials when a plurality of types of raw materials are mixed and charged into a blast furnace.

DESCRIPTION OF SYMBOLS 10 Raw material charging device 11a, 11b Top hopper 12 Collecting chute 13 Vertical chute 14 Turning chute 15a, 15b Flow control gate 16a, 16b Load cell 20 Blast furnace

Claims (5)

When mixing and charging a plurality of types of raw materials into a blast furnace, a method for estimating the mixing ratio of the mixed raw materials,
A first step of determining a volume flow rate of the mixed raw material discharged from the hopper;
A second step of measuring the weight of the hopper when continuously discharging the mixed raw material from the hopper;
A third step of determining a mass flow rate of the mixed raw material at a predetermined time based on the weight of the hopper measured in the second step;
Based on the mass flow rate of the mixed raw material obtained in the third step, the volume flow rate of the mixed raw material determined in the first step is constant, and is added to the parent phase raw material among the mixed raw materials. And a fourth step of estimating a mixing ratio of the added raw material. A method for estimating a raw material mixing ratio of a blast furnace. The blast furnace raw material mixing ratio estimation method according to claim 1, wherein the parent phase raw material is sintered ore or ore. The method for estimating a raw material mixture ratio of a blast furnace according to claim 1 or 2, wherein the weight of the hopper in the second step is measured using a load cell provided in the hopper. In the fourth step, the matrix material and the mass flow rate W _A of the additive material at a predetermined time _{t, t,} W _{B, t} and the following formulas (1), calculated by (2), the added material The raw material mixing ratio estimation method for a blast furnace according to any one of claims 1 to 3, wherein the mixing ratio _Mt is estimated by the following equation (3).
_{W A, t = (ρ A} ρ B V-ρ A W t) / (ρ B -ρ A) ···· (1)
W _{B, t} = W _t −W _{A, t} (2)
M _t = W _{B, t} / W _t (3)
Where W _{A, t is} the mass flow rate of the parent phase raw material at a predetermined time t, W _{B, t is} the mass flow rate of the added raw material at the predetermined time t, W _{t is} the mass flow rate of the mixed raw material at the predetermined time t, and ρ. _A : Bulk density of parent phase raw material, ρ _B : Bulk density of additive raw material, V: Volume flow rate of mixed raw material, M _t : Mixing ratio When there are a plurality of the additive raw materials,
The fourth step includes
While calculating the mass flow rate of one additional raw material having the bulk density farthest from the bulk density of the matrix phase raw material among the multiple types of additive raw materials, the matrix phase raw material and the multiple types of additive raw materials A fifth step of calculating the mass flow rate of the raw material in a mixed state with the other additive raw material other than the one additive raw material,
A sixth step of calculating a mass flow rate of the matrix phase raw material and a mass flow rate of the other additive raw materials;
Performing the fifth step and the sixth step one or more times in this order, calculating a mass flow rate of each of the additive materials, and estimating a mixing ratio of each of the additive materials; The blast furnace raw material mixing ratio estimation method according to claim 4, wherein: