JP6747232B2 - Blast furnace raw material mixing ratio estimation method - Google Patents

Description

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

Generally, in a blast furnace in the production of pig iron, ore, coke, etc. are sequentially charged and deposited as a charge from the furnace top, 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 of the ore is directly reduced by the coke to form the softening cohesive zone. , Droplets, that is, hot metal.

Here, ore is a general term for iron raw materials. In the Japanese blast furnace operation, for example, it is composed of 85% sinter, 10% lump ore, and 5% pellets. Furthermore, various brands are mixed with 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 has different density and particle size from the sintered ore, which is the main component of the ore. Therefore, segregation occurs without being uniformly dispersed in the ore layer. For example, the density of small coke to promote the reduction of sinter is about 1/3 of that of ore. Therefore, when the ore and the small coke are transferred to the blast furnace, they are segregated at the time of charging and discharging at the hopper in the middle of the transfer. As a result, when charging the blast furnace, the charging amount becomes uneven 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, The weight of each of the sinter and coke is measured to estimate the mixing degree of the raw materials.

Japanese Patent No. 2808343 JP, 2007-204791, A

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

The present invention has been made in view of the above points, and an object thereof is to provide a method for easily estimating a mixing ratio of mixed raw materials when a plurality of types of raw materials are mixed and charged into a blast furnace. ..

In order to achieve the above-mentioned object, the present inventor investigated the discharge behavior of various mixed granules from the hopper, and found that the raw materials adopted in the blast furnace method (raw material charging method) and the mixing ratio of the raw materials (blending ratio) In the range of (rate), it was found that the volumetric flow rate of the mixed raw material discharged from the hopper can be considered to be almost constant regardless of the type of the mixture mixed with the ore and the mixing ratio thereof.

The present invention has been made on the basis of such findings, and is a method of estimating a mixing ratio of a mixed raw material when mixing and charging a plurality of raw materials into a blast furnace, wherein the mixed raw material is a mother material. The first step of determining the volumetric flow rate of the mixed raw material discharged from the hopper, which comprises a phase raw material and a kind of additive raw material, and the weight of the hopper when continuously discharging the mixed raw material from the hopper. Determined in the second step of measuring, the third step of obtaining the mass flow rate of the mixed raw material at a predetermined time based on the weight of the hopper measured in the second step, and the first step the volumetric flow rate of the mixed raw material is constant with, based on the mass flow rate of the mixed raw material obtained in the third step, prior to chromatic Ki添 a fourth step of estimating the mixing ratio of the pressurized material, the Then, in the fourth step, the mass flow rates W _A,t and W _B,t of the mother phase raw material and the additive raw material at a predetermined time t are calculated by the following formulas (1) and (2), respectively, It is characterized in that it is a step of estimating the mixing ratio M _t of the added raw material by the following formula (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 mother phase raw material at the predetermined time t, WB _{,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, ρ _A : bulk density of mother phase raw material, ρ _B : bulk density of additive raw material, V: volumetric flow rate of mixed raw material, M _t : mixing ratio
The present invention according to another aspect is a method of estimating a mixing ratio of a mixed raw material when a plurality of raw materials are mixed and charged into a blast furnace, and the mixed raw material is a mother phase raw material and a plurality of types of additions. A first step of determining a volumetric flow rate of the mixed raw material made of raw materials and discharged from the hopper, and a second step of measuring the weight of the hopper when continuously discharging the mixed raw material from the hopper. And a third step of obtaining the mass flow rate of the mixed raw material at a predetermined time based on the weight of the hopper measured in the second step, and the volume of the mixed raw material determined in the first step. A fourth step of estimating the mixing ratio of the additive raw material based on the mass flow rate of the mixed raw material obtained in the third step with the flow rate kept constant; Among the plurality of types of additive raw materials, the mass flow rate W _B,t of one additive raw material having a bulk density farthest from the bulk density of the mother phase raw material is calculated by the following formula (2), and _A fifth step of calculating a mass flow rate W _A,t of a raw material in a state in which a phase raw material and an additive raw material other than the one additive raw material among the plurality of types of additive raw materials are mixed by the following formula (1): And the sixth step of estimating the mixing ratio M _t of the one additive raw material 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 raw material in a state in which the mother phase raw material and the other additive raw material are mixed at a predetermined time t , WB _{,t is} the mass flow rate of one additive raw material at the predetermined time t, W _t : mass flow rate of the mixed raw material at a predetermined time t, ρ _A : bulk density of the raw material in a state where the mother phase raw material and another additive raw material are mixed, ρ _B : bulk density of one additive raw material, V: mixed raw material Volumetric flow rate, M _t : mixing ratio
In the present invention according to the another aspect, in the fourth step, among the other additive raw materials, the mass flow rate of the other additive raw materials is set in order of having a bulk density separated from the bulk density of the mother phase raw material. You may further have the 7th process of calculating and may estimate the mixing ratio of the said other additive raw material in the said 6th process.

The mother phase raw material may be sinter or ore.

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

According to the present invention, by performing the first step to the fourth step, it is possible to appropriately estimate the mixing ratio of the mixed raw material (mixing ratio of the added raw material). Moreover, in estimating the mixing ratio, the only thing that actually needs to be measured is the weight of the hopper, and the two weight measuring means, particularly the coil sensor, are not required as in the conventional case. Therefore, the mixture ratio can be easily estimated.

It is explanatory drawing which shows typically the outline of a structure of the raw material charging apparatus 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 volumetric flow rate of the mixed raw material, (b) shows the change over time of the mass flow rate of the sinter, (c). Shows the change over time in the mass flow rate of small coke. It is a flowchart which shows the example of a 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 a 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 change over time of the actual value and estimated value of the mixing ratio of small coke is shown. In Example 2, the time-dependent change of the actual value and estimated value of the silica mixing ratio is shown.

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

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

The raw material charging device 10 is a parallel hopper type raw material charging device and charges the raw material into the blast furnace 20. The raw material charging device 10 has a plurality of, for example, two furnace top hoppers 11a and 11b, a collecting chute 12, a vertical chute 13, and a swirling 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 11a and 11b are arranged in parallel and opposite to each other, and the discharge ports of the furnace top hoppers 11a and 11b 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 respective furnace top hoppers 11a and 11b. Load cells 16a, 16b for measuring the weight of the furnace top hopper 11 are provided in the furnace top hoppers 11a, 11b. The load measuring device that measures the weight of the furnace top hopper 11 is not limited to the load cell 16, and any other load measuring device can be used. Raw material R for one charging is temporarily stored in each of the furnace top hoppers 11a and 11b. While the raw material R in one furnace top hopper 11a is charged into the furnace, the raw material R is received in the other furnace top hopper 11b. By repeating this alternately, the time required for receiving and charging the raw material R is shortened.

The raw material R of the furnace top hopper 11a is, for example, a mixed material for forming an ore layer in the blast furnace 20. In this embodiment, an example will be described in which a material obtained by mixing an ore, which is a matrix material, and a small coke, which is an additive material added to the matrix material, is used as the mixed material. The raw material R of the furnace top hopper 11b is, for example, coke for forming a coke layer in the blast furnace 20.

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 collecting chute 12, and causes the raw material R discharged from the collecting chute 12 to flow to the swirling chute 14.

The swirling chute 14 receives the raw material R discharged from the vertical chute 13 and loads 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 about the vertical chute 13 by a drive mechanism (not shown). Further, the turning chute 14 is configured to be tiltable (rotatable) in the vertical direction about the vertical chute 13, and the turning radius of the turning chute 14 can be arbitrarily changed.

Then, in the raw material charging device 10, the raw material R in the furnace top hoppers 11a and 11b is subjected to flow rate adjustment by the flow rate adjusting gates 15a and 15b, and is discharged to the collecting chute 12. The raw material R falls on the swirling chute 14 through the collecting chute 12 and the vertical chute 13, and is charged into the blast furnace 20 from the tip of the swirling chute 14.

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

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

The simulation was carried out by using the discrete element method (DEM) under the condition that two kinds of raw materials having different densities, that is, sinter and small coke were mixed in the hopper, and the mixed raw material was discharged from the hopper. It was done using. As the calculation conditions of this simulation, the average particle diameter of the sinter ore was 25 mm, the weight of the sinter was 28 ton, the average particle diameter of the small lump coke was 35 mm, and the weight of the small lump coke was 1.8 ton.

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

With reference to FIG. 2, it was confirmed that the volumetric flow rate of the mixed raw material was substantially constant over time, and new knowledge was obtained.

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

Here, the volumetric flow rate V of the mixed raw material is represented by the following equation (5). Then, the above-mentioned new finding that the volumetric flow velocity V of the mixed raw material is constant can be said in other words that the bulk density ρ of the mixed raw material is constant. That is, even if a plurality of types of raw materials flow in the hopper, the bulk density ρ of the mixed raw material when discharged from the hopper can be regarded as constant.
V=W/ρ (5)
However, V: volumetric flow rate of the mixed raw material, W: mass flow rate of the mixed raw material, ρ: bulk density of the mixed raw material

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

Looking back, the above formula (4) is a formula assuming a single raw material, and a mixed raw material in which a plurality of types of raw materials are mixed was not assumed. From this point of view, it can be said that the finding that the volumetric flow rate V of the mixed raw material is constant is new.

<3. Method for Estimating Raw Material Mixing Ratio of Blast Furnace According to First Embodiment>
Next, a method for estimating the raw material mixture ratio of 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 method for estimating the raw material mixture ratio of the blast furnace.

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

When the theoretical formula is used, the volume flow rate V of the mixed raw material is determined using, for example, the following formula (6). This expression (6) is derived by dividing the expression (4) by the bulk density ρ, because the bulk density ρ of the mixed raw material can be regarded as constant in the expression (4) as described above. The particle diameter D _p of the mixed raw material can be determined by sampling the mixed raw material of the batch before introducing it into the hopper and measuring the particle size with 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 discharge port of hopper

When the discharge time of the mixed raw material is used, the volume flow rate V of the mixed raw material is determined by using, for example, formula (7). 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). Note that the discharge time θ may be the discharge time of the mixed raw material in the previous batch, instead of the discharge time of the batch, as long as the gate opening degree is the same.
V=Q/ρθ (7)

(Step S2)
Next, the load cell provided in the hopper continuously measures the weight Q _h of the hopper containing the mixed raw material as the content.

(Step S3)
Then, based on the weight _{Q h} hopper measured in step S2, obtaining a change amount _dQ h / dt of the weight _{Q h} hopper at a given time t. This dQ _h /dt is the mass flow rate W _t of the mixed raw material at the 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 ore which is a raw material for the mother phase, and B indicates small coke which is a raw material for addition.
_Wt =WA _,t +WB _,t ...(8)
V=W _A,t /ρ _A +W _B,t /ρ _B ... (9)
However, W _t : mass flow rate of the mixed raw material at a predetermined time t, W _A,t : mass flow rate of ore at a predetermined time t, WB _,t : mass flow rate of small coke at a predetermined time t, V: Volumetric flow rate of mixed raw material, ρ _A : bulk density of ore, ρ _B : bulk density of small coke

The following equations (1) and (2) are obtained by solving the above equations (8) and (9). Then, the volumetric flow rate V of the mixed raw material determined in step S1 is made constant, and the mass flow rate W _{A,t of the} ore and the mass of the small coke are calculated based on the mass flow rate W _t of the mixed raw material calculated in step S3. The flow rate W _B,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 equation (3) is used to calculate the mixed raw material 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, by performing steps S1 to S5, it is possible to appropriately estimate the mixing ratio of the small coke in the mixed raw material. Moreover, 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 the two weight measuring means, particularly the coil sensor, are not required as in the conventional case. Therefore, the mixture ratio can be easily estimated.

Then, the mixing ratio thus properly estimated can be utilized as follows in the raw material charging process 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.

In addition, for example, when the mixed raw material is charged into the blast furnace, the angle of the swirling chute is appropriately controlled based on the mixing ratio estimated by the method of the present invention. Then, in the blast furnace, a mixed raw material having a high mixing ratio of small coke can be charged at a position where the small coke is consumed in the radial direction of the furnace.

In the above embodiment, the case where the mother phase raw material is ore and the additive raw material is small coke has been described, but the mother phase raw material and the additive raw material are not limited thereto. The present embodiment can be applied to a mixture of sinter, lump ore, and pellets having various ratios as a mother phase raw material. Further, in the present embodiment, as additive raw materials, ferrocoke, coal-bearing agglomerated ore, reduced iron powder, scrap ore and other blast furnace materials, and auxiliary materials such as limestone, serpentine, apatite, and silica are used. It can also be applied in cases. That is, if the particles of the additive raw material have a density difference from the particles of the mother phase raw material, the present embodiment can be applied to estimate the mixing ratio of the additive raw material.

<4. Raw Material Mixing Ratio Estimation Method According to Second Embodiment>
Next, a method of estimating a raw material mixture ratio 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 method for estimating the raw material mixture ratio of the blast furnace. In the present embodiment, the mother phase raw material A (ore), additive raw material B (small lump coke), and additive raw material C (silica) are used, and the bulk density of each raw material A, B, C is ρ _A >ρ _C >ρ _B And The additive raw material C does not have to be silica.

(Steps S1 to S3)
Steps S1 to S3 in the second embodiment are the same as steps S1 to S3 in the above-described first embodiment, respectively, and therefore description thereof will be omitted.

(Step S4')
A state in which the mother phase 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 represented by 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 silica are mixed at a predetermined time t, ρ _AC : bulk density in a state where ore and silica are mixed

By solving the above equations (8′) and (9′), the following equations (1′) and (2′) are obtained. Then, the volumetric flow rate V of the mixed raw material determined in step S1 is set constant, and the mass flow rate W _{AC,t of the} ore and silica and the small coke based on the mass flow rate W _t of the mixed raw material calculated in step S3. The mass flow rate W _{B,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 velocity W _B,t of the small coke calculated in step S4′, the volume flow velocity V _AC,t of the ore and silica at a predetermined time t is calculated using the following formula (10). To do.
V _AC,t =V−W _B,t /ρ _B (10)

(Step S6')
Next, the mass flow velocities of the mother phase raw material A and the additive raw material C are separated from W _AC,t to obtain them. 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'')
However, W _C,t : Mass flow rate of silica at a predetermined time t

By solving the above equations (8″) and (9″), the following equations (1″) and (2″) are obtained, and from these equations, the mass flow rate W _{A,t of the} ore and the silica stone are obtained. The mass flow rate W _{C,t of} is calculated.
W _A,t =(ρ _A ρ _C VAC _,t −ρ _A W _AC,t )/(ρ _C −ρ _A )... (1″)
W _C,t =W _AC,t −WA _,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} silica calculated in step S6′. _{, t} , the mixing ratios M _B,t and M _C,t of the additive raw materials B and C in the mixed raw material are estimated using the following equations (3′) and (3″).
M _B,t =W _B,t /W _t ... (3')
M _C,t =W _C,t /W _t ... (3'')

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

In the above embodiment, the case where the mother phase raw material A is ore, the additional raw material B is small coke, and the additional raw material C is silica is explained, but the mother phase raw material and the additional raw material are not limited to this. .. The present embodiment can be applied to a mixture of sinter, lump ore, and pellets having various ratios as a mother phase raw material. Further, in the present embodiment, as the additive raw material, when ferrocoke, coal-bearing agglomerated ore, reduced iron powder, blast furnace raw material such as scrap ore, and auxiliary raw materials such as limestone, serpentine, and granite are used. Can also be applied. That is, if the particles of the additive raw material have a density difference from the particles of the mother phase raw material, the mixing ratio of the additive raw material can be estimated by applying the present embodiment. Then, the mass flow rate may be obtained in order from the one having the largest density difference from the mother phase raw material.

For example, in the case where there are three types of additive raw materials 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 a state in which the additive raw materials C and D having close bulk densities are mixed as one mixed particle, steps S4′ to S6′ are performed, and the mass flow rate of the additive raw material B and the additive raw materials C and D are mixed. Calculate the mass flow rate. After that, of the additive raw materials C and D, the state in which the mother phase raw material A and the additive raw material D having a close bulk density are mixed is considered as one mixed particle, and steps S4′ to S6′ are further performed to determine the mass of the additive raw material C. The flow rate and the mass flow rate of the added raw material D are calculated. Then, in step S7′, the mixing ratio of the additive raw materials B, C and D in the mixed raw material is estimated.

The preferred embodiment of the present invention has been described above with reference to the accompanying drawings, but the present invention is not limited to such an example. It is obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the idea described in the claims, and naturally, they also belong to the technical scope of the present invention. Understood.

In the above embodiments, the case where the present invention is applied to the furnace top hopper has been described, but the present invention can be applied to all other hoppers (for example, surge hopper).

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

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

Further, in the examples, the volumetric flow rate V of the mixed raw material discharged from the furnace top hopper was obtained by using the above-mentioned formula (6). In the formula (6), the particle diameter D _p of the mixed raw material is 18 mm, the friction coefficient f is 0.4, the opening angle φ of the furnace top hopper is 45 degrees, and the diameter D ₀ of the discharge port of the hopper is 655 mm. .. Then, the volumetric flow rate V of the mixed raw material was found to be 0.71 m ³ /s.

Then, based on the mass flow rate W _t of the mixed raw material and the volume flow rate V of the mixed raw material, the mass flow rate W _B,t of the small coke was calculated using the above equation (2). 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 W _{B,t of} the small coke was obtained as shown in FIG.

On the other hand, in the comparative example, an experiment was carried out using a 1/5 scale test apparatus that is similar to an actual 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 obtained as shown in FIG.

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

The effects of the present invention (second embodiment) will be described below. Specifically, mass flow rates W _B,t and W _C, when a plurality of types of additive raw material B (small lump coke) and additive raw material C (silica) are mixed with the mother phase raw material A (ore) Verification of _t (mixing ratios M _B,t and M _C,t ) was performed using the discrete element method (DEM). In this verification, the average particle size of the sinter ore was 25 mm, the weight of the sinter was 28 ton, the average particle size of the small lump coke was 35 mm, the weight of the small lump coke was 1.8 ton, and the average particle size of silica stone was 30 mm, and the weight of silica stone was 3.0 ton. All the mixed particles were loaded into a hopper, then discharged from the hopper, and the brand and weight of the discharged particles were investigated.

8 and 9 show the results (actual values) of the DEM simulation of changes over time in the mixing ratio of small coke and silica stones, and the estimated values obtained from 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 ρ _AC when the sinter ore and silica were mixed was set to 1.7 ton/m ³ .

As can be seen from FIGS. 8 and 9, the tendency of the temporal change of the mixing ratio of the small coke and the silica is very large in the actual value simulated by the DEM and the estimated value by the equations (3′) and (3″). Have a good correspondence. Therefore, it was found that the accuracy of the mass flow rate of the additive raw material is extremely high even when a plurality of brands calculated in the present invention are used as the additive raw material.

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

10 Raw material charging device 11a, 11b Top hopper 12 Collecting chute 13 Vertical chute 14 Swiveling chute 15a, 15b Flow rate adjusting gate 16a, 16b Load cell 20 Blast furnace

Claims (5)

A method of estimating a mixing ratio of mixed raw materials when charging a plurality of kinds of raw materials into a blast furnace,
The mixed raw material consists of a mother phase raw material and a kind of additive raw material,
A first step of determining a volumetric 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 obtaining 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,
The volume flow rate of the raw material mixture is determined in the first step is constant, based on the mass flow rate of the mixed raw material obtained in the third step, for estimating the mixing ratio before Ki添 pressurized material and the fourth step, the possess,
In the fourth step, the mass flow rates W _A,t and W _B,t of the mother phase raw material and the additive raw material at a predetermined time t are calculated by the following formulas (1) and (2), respectively, and the additive raw material is calculated. A method for estimating a raw material mixture ratio of a blast furnace, which is a step of estimating the mixture ratio M _t of the above 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 mother phase raw material at the predetermined time t, WB _{,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, ρ _A : bulk density of mother phase raw material, ρ _B : bulk density of additive raw material, V: volumetric flow rate of mixed raw material, M _t : mixing ratio A method of estimating a mixing ratio of mixed raw materials when charging a plurality of kinds of raw materials into a blast furnace,
The mixed raw material is composed of a mother phase raw material and a plurality of types of additive raw materials,
A first step of determining a volumetric 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 obtaining 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,
A volumetric flow rate of the mixed raw material determined in the first step is constant, and a mixing ratio of the additive raw material is estimated based on the mass flow rate of the mixed raw material obtained in the third step. And a process,
The fourth step is
Of the plurality of types of additive raw materials, the mass flow rate W of one additive raw material having a bulk density farthest from the bulk density of the mother phase raw material. _B,t Is calculated by the following formula (2), and the mass flow rate W of the raw material in a state where the mother phase raw material and the additive raw material other than the one additive raw material among the plurality of types of additive raw materials are mixed. _{A, t} And a fifth step of calculating by the following equation (1),
Mixing ratio M of the one additive material _t A method for estimating a raw material mixture ratio of a blast furnace, comprising a sixth step of estimating by the following formula (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)
However, W _{A, t} : Mass flow rate of the raw material in a state in which the mother phase raw material and the other additive raw material are mixed at a predetermined time t, W _B,t : Mass flow rate of one additive raw material at a predetermined time t, W _t : Mass flow rate of the mixed raw material at a predetermined time t, ρ _A : Bulk density of the raw material in a state where the parent phase raw material and other additive raw materials are mixed, ρ _B : Bulk density of one additive raw material, V: Volume flow rate of mixed raw material, M _t : Mixing ratio The fourth step further includes a seventh step of calculating a mass flow rate of the other additive raw material in the order of having a bulk density separated from the bulk density of the mother phase raw material among the other additive raw materials. Then
The method for estimating a raw material mixture ratio of a blast furnace according to claim 2, wherein the mixture ratio of the additional raw material is estimated in the sixth step. The blast furnace raw material mixing ratio estimation method according to claim 1, wherein the mother phase raw material is sinter or ore. The measurement of the weight of the hopper in the second step is performed using a load cell provided in the hopper, and the raw material mixing ratio of the blast furnace according to any one of claims 1 to 4. Estimation method.