JPS6238404B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is characterized in that raw materials are charged from a belt conveyor through a rotating chute equipped with a discharge gate valve to a bell hopper, and then charged into a furnace. This invention relates to a method for charging raw materials to a relay hopper in a bell-type raw material charging device for a vertical furnace.

(Prior art) Raw materials such as ore, limestone, and coke that are charged into a blast furnace are generally stored by brand in a surge hopper installed outside the furnace. Each brand is cut out onto a conveying device such as a belt conveyor or a skip, and transported to the top of the blast furnace by this conveying device, and then passed through a rotating chute or a rotating hopper (hereinafter referred to as a rotating chute) installed at the top of the blast furnace. The materials are then charged into a fixed hopper, a bell hopper, etc. (hereinafter referred to as a relay hopper).

After being charged into the relay hopper, the raw material deposited on the bell is discharged at the appropriate time by opening the bell and charged into the furnace via a raw material repellent such as a movable armor. In order to stabilize blast furnace operation and stabilize the quality of hot metal, it is strongly required to uniformize the distribution of raw materials charged into the furnace.

The above-mentioned rotating chute and raw material repulsion device are installed for this purpose.
No. 148709 is a system in which an on-off valve is provided at the discharge port of a rotating chute, a predetermined amount of raw material is received into the rotating chute with the on-off valve closed, and then the on-off valve is opened and the chute is rotated to distribute the raw material. According to this method, the directionality of the material flow from the belt conveyor is eliminated and the material charging distribution in the circumferential direction in the relay hopper is improved to some extent. It is difficult to uniformly distribute the raw material in the circumferential direction. In addition, it is difficult to adopt this method if there is no margin in the charging schedule.

Fig. 1 shows the relay hopper and the material storage in the furnace when the belt conveyor 1 and the rotating chute 2 are used as the device for conveying the raw material M to the top of the furnace, and there is unevenness in the amount of raw material discharged from the rotating chute 2. This is an example of the bias in the input distribution.

As shown in this figure, if the amount of raw material discharged from the rotating chute 2 to the fixed hopper 3 having a plurality of discharge ports in the circumferential direction is different between the right side (V ₁ ) and the left side (V ₂ ), This appears as a bias in the charging distribution in the fixed hopper 3, and this bias in the charging distribution also appears as a similar bias in the small bell hopper 4 and large bell hopper 5, and is also resolved through the raw material repulsion device. It is normal for this to occur as a bias in the charging distribution (ΔH) even in the furnace interior 6.

Therefore, in order to alleviate this bias in the raw material charging distribution, first, the directionality of the raw material flow from the belt conveyor 1 to the rotating chute is eliminated, and at the same time, the raw material discharge distribution in the fixed hopper circumferential direction is changed in this rotating chute. A controllable discharge operation is required to make the discharge uniform.

(Problems to be Solved by the Invention) The present invention has been made in response to the above-mentioned demands, and is a vertical furnace in which raw materials from a belt conveyor are charged into a relay hopper via a rotating chute. In the type material charging method, the controllability of the material charging distribution in the furnace is improved by eliminating the directionality of the material from the belt conveyor and uniformly distributing the material from the rotating chute to the relay hopper circumferential direction. The purpose of this project is to contribute to stabilizing the operation of vertical furnaces and stabilizing the quality of hot metal.

(Means for Solving the Problems) The present invention involves charging raw materials from a belt conveyor into a relay hopper via a rotating chute equipped with a discharge gate valve, and then loading the material into a furnace by opening the bell. In the method of charging raw materials to a relay hopper in a bell-type raw material charging device of a vertical furnace, the raw material brand (raw material characteristics) and the amount of raw material supplied are , the supply time and the capacity value of the rotating chute are grasped in advance, and the raw material discharge rate from the rotating chute to the relay hopper is kept constant within the range in which the supplied raw material is stored in the rotating chute and the raw material does not overflow. A bell-type raw material for a vertical furnace, which is characterized in that the number of turns of the rotating chute, the rotation speed, and the opening degree of the rotating discharge gate valve of the rotating chute are calculated and controlled, and the distribution of the raw material in the circumferential direction of the relay hopper is controlled. This is a method of charging raw materials to a relay hopper in a charging device.

In the method for charging raw materials to a relay hopper in a bell-type raw material charging device for a vertical furnace according to the present invention, the second
As shown in the figure, a discharge gate valve 7 for adjusting the opening degree is provided at the discharge port of the swing chute 2, and this discharge gate valve allows the material M to be discharged from the belt conveyor 1 within a range that does not overflow from the swing chute 2. The rotating chute is designed to provide resistance to the flow, eliminate the directionality of the raw material flow, and to make the amount of raw material discharged from the discharge gate valve 7 of the rotating chute 2 uniform in the circumferential direction of the relay hopper (V ₁ = V ₂ ). Calculate and control the opening degree, number of times, and rotation speed of the discharge gate valve.

As a result, the relay hopper, that is, the fixed hopper 3, which has discharge ports at approximately equal intervals in the circumferential direction, the small bell hopper 4, and the large bell hopper 5, can make the charging distribution of raw materials in the circumferential direction uniform, and 6. The raw material charging distribution in the circumferential direction can also be made uniform (ΔH=0).

During the discharge of raw materials from the above-mentioned rotating chute 2, the opening degree of the discharge gate valve is fixed, so in order to equalize the amount of raw material discharged in the circumferential direction of the relay hopper, the rotation speed is fixed and the number of turns is fixed. The turning operation will be computationally controlled so that it becomes an integer.

Furthermore, since the optimum range for the amount and charging time of each raw material to be charged into the furnace is determined, the discharge time from the rotating chute is also limited so as to satisfy these conditions.

Therefore, it is necessary to know the amount and supply time (velocity) of the raw material supplied from the belt conveyor 1 to the rotating chute 2, and also to understand the capacity value of the rotating chute 2 in order to obtain conditions in which the raw material does not overflow in the rotating chute 2. I need. Furthermore, in order to determine the opening degree of the discharge gate valve of the rotating chute 2 and the optimum conditions for swirling, the raw material brand, that is, the raw material characteristics such as the particle size, density, and friction coefficient of the raw material are also important factors.

The present applicant has previously proposed a rotating chute in which a discharge gate valve is provided at the discharge port as an invention in Japanese Patent Application No. 56-153740, and this is used, for example, in the method of the present invention.

Various forms of calculation control such as the opening degree of the discharge gate valve 7 of the swing chute 2, the number of swings, the swing speed, the discharge time to the relay hopper (discharge speed), etc. in carrying out the method of the present invention are possible, but the following methods are possible. It can be said that the calculation control form is universal.

Calculation control example 1 The opening degree of the discharge gate valve of the swing chute is initially set, and the discharge time from the swing chute to the relay hopper is calculated according to the amount of raw material supplied from the belt conveyor 1 and the supply speed (time), and the swing is performed. The rotation speed is calculated and controlled so that the number becomes an integer.

Calculation control example 2 The opening degree of the discharge gate valve 2 of the swing chute is calculated and controlled based on the raw material supply amount and supply speed (time) in the belt conveyor 1, and the capacity of the swing chute, and the material discharge time from the swing chute 2 to the relay hopper is controlled. (discharge speed) and control the turning speed so that the number of turns becomes an integer.

Arithmetic control example 3 The integer number of turns and rotation speed of the rotating chute are initially set for each material brand, and the opening degree of the discharge gate valve 7 of the rotating chute 2 is adjusted according to the amount of raw material supplied from the belt conveyor 1 and the supply speed (time). is calculated and controlled to calculate and control the time for discharging the raw material from the rotating chute 2 to the relay hopper.

There are various possible receiving sequences from the belt conveyor 1 to the rotating chute 2 at the top of the furnace corresponding to the above calculation control example of the present invention, but three typical examples are as shown in FIG. can give.

In the present invention, this raw material receiving sequence can be selected arbitrarily.

Raw material reception sequence example A (Figure 3 A) Before starting to receive raw materials from the belt conveyor 1 to the swing chute 2, the opening degree of the discharge gate valve 7 of the swing chute is calculated or set in advance in the calculation control examples 1 to 3 above. The raw material is received from the belt conveyor 1 into the rotating chute 2 after the opening is fixed at the specified opening.

In this case, the discharge time of the raw material from the discharge gate valve of the swing chute 2 is delayed by the length of the opening of the discharge gate valve of the swing chute 2 which is narrowed.

Here, t _B is the discharge time of the material from belt conveyor 1 to the rotating chute, te is the receiving time to the rotating chute, SO is the set opening of the discharge gate valve, ti is the discharge time from the discharge gate valve, O is the opening of the discharge gate valve. represents degree.

Raw material reception sequence example B (Figure 3 B) After the discharge gate valve of the swing chute is fully closed and the entire amount of raw material has been received from the belt conveyor 1 to the swing chute 2, the opening degree of the discharge gate valve of the swing chute is changed. is set to the opening degree calculated and set in the calculation control examples 1 and 3 above, and the raw material is discharged from the rotating chute.

In this sequence example, the raw material is stored once in the rotating chute 2 and then discharged by opening the discharge valve, so it is particularly effective when charging a small amount of raw material, but it is difficult when there is no margin in the charging schedule. There is.

Raw material reception sequence example C (Figure 3 C) Fully close the discharge gate valve of the rotating chute, start receiving raw materials from the belt conveyor, keep it closed for a period of time to prevent overflow from the rotating chute, and then close the discharge gate valve of the rotating chute. is opened to the opening degree calculated in the calculation control example 3, and the raw material is discharged from the rotating chute.

Here, c represents the discharge gate valve being fully closed.

This sequence example C is similar to sequence example B,
Since the raw material is once stored in the rotating chute and then discharged by opening the discharge gate valve, it can be said to be effective when charging a small amount of raw material.

A more specific explanation will be given using mathematical formulas based on the calculation control examples 1 to 3 described above.

(1) In the case of calculation control example 1 If the opening degree Do ₁ of the discharge gate valve of the swing chute is initially set, the material discharge speed from this discharge gate valve will be
Q ₁ is expressed as follows.

Q ₁ = Ki〓Do ^m ₁ ... Here, Ki is the characteristic value of the raw material such as density, particle size, internal friction coefficient, etc., and is determined for each brand. m is an index expressing the relationship between the hydraulic diameter of the gate of the discharge gate valve and the discharge speed, and is usually on the order of 2.5.

By using the formula and determining Ki and m through experiments or actual furnace tests, the discharge speed Q ₁ from the discharge gate valve of the rotating chute can be determined from the characteristic values of the discharged raw material.

On the other hand, the conveyance amount of raw materials from the belt conveyor W ₁
is input at the time of discharge from the surge hopper, and the discharge time _t1 from the discharge gate valve is expressed by the formula.

t ₁ = W ₁ / Q ₁ 〓3600... Here, the opening degree of the relay hopper and the discharge gate valve of the swing chute is calculated using the number of turns of the swing chute as an integer.
D ₃ is the charging amount of raw material discharged from the surge hopper W ₃
and the brand, and calculate the amount of discharge (t/) to the relay hopper.
hr) Calculate from Q ₃ .

Q ₃ = W ₃ t ₃ ... D ₃ = (Q ₃ / K ₃ ) = ... However, as in the case of ( ₂ ), considering the overflow condition of the rotating chute, Emissions (t/hr) Q _B and Q ₃
From the relationship, it is necessary to satisfy (Q _B −Q ₃ )/(T〓ρ)<V...

Here, T is the time for discharging the raw material from the belt conveyor.

In order to maintain charging balance in the circumferential direction, the number of turns n ₁ is calculated from the maximum possible turning speed Rmax (rpm) of the turning chute.

t ₁ (Rmax/60)=n _i ... However, in this case, n ₁ may be a non-integer, and in order to satisfy the above-mentioned integer turning condition, ni is rounded off to calculate the integer number of turns n' ₁ .

Next, based on this n ₁ ′, the turning speed R ₁ is calculated within a range not exceeding Rmax.

R ₁ = 60〓n ₁ /t ₁ ... The formula is to ensure the maximum number of rotations, but this is just an example, and if there is an optimal range depending on the brand (raw material characteristics) and amount of raw materials, By inputting a value in the optimum range to Rmax, the above integer turning condition is always satisfied.

(2) Case of calculation control example 2 This example is for calculating and controlling the initial setting value of the opening degree of the discharge gate valve of the swing chute in the example (1), and it calculates the supply amount from the belt conveyor and the swing chute. This aims to improve the charging balance in the circumferential direction of the relay hopper by reducing the opening degree of the discharge gate valve as much as possible to prevent overflow and depositing the raw material in consideration of the capacity value of the relay hopper.

Raw material supply amount from belt conveyor (t ₁ /hr)
Let Q _B be the discharge amount (t/hr) from the discharge gate valve of the rotating chute, and Q ₂ be the discharge amount (t/hr) from the discharge gate valve of the rotating chute, then the material deposition rate in the rotating chute will be Q _B −Q ₂ .

Here, if the capacity of the rotating chute is V and the discharge time of the belt conveyor is T, then the condition for no overflow is established.

(Q _B −Q ₂ )T/ρ<V where ρ is the density of the raw material.

Calculating Q ₂ in the formula yields the formula.

Q ₂ = ρV/TQ _B ... ρ, Q _B and T are input when the material is discharged from the surge hopper, and Q ₂ is calculated.

and the opening degree D ₂ of the discharge gate valve of the swing chute
is calculated by the formula.

Q ₂ = Ki.D ₂ m D ₂ = n (Q ₂ Ki) = ... When discharging raw materials while depositing them based on the opening degree D ₂ of this discharge gate valve, ( 1) Control the turning speed of the turning chute as in the example.

In this example, if the capacity V of the rotating chute is set to be smaller than the actual capacity, it is possible to be on the safe side against overflow and to select the accumulation level.

FIG. 4 shows a simple concrete example of control in the above calculation control examples 1 and 2.

(3) Case of calculation control example 3 When the number of turns R ₃ and its integer number of turns n ₃ are set, the discharge time t ₃ is calculated.

(60/R ₃ )〓n ₃ = t ₃ ... (Example) Grasping of various information for calculation control of the rotation of the swing chute and the opening degree of the discharge gate valve of the swing chute in the present invention, and an example of calculation control , will be explained based on FIG.

In order to obtain a predetermined amount of the required brand of raw material based on a preset raw material charging schedule, each brand of raw material is weighed from each ore storage tank B ₀ , B ₁ and the hopper S ₀ ,
They are each weighed in _S1 , cut into a predetermined amount onto belt conveyor BC, and charged into surge hopper 8.

In this process, the total weighed value of the cut-out amount for each brand is inputted to the blast furnace general control unit 13 as, for example, the raw material supply amount for one batch.

The raw material characteristics determined by the raw material brand are determined experimentally, and design values are input into the blast furnace general control section 13 as the capacity values of the rotating chute 2, respectively.

After the raw material M charged into the surge hopper 8 is temporarily stored, it is cut into the charging belt conveyor 1 at a preset timing and speed, and charged into the rotating chute 2.

A cutting start signal and a cutting completion signal from the surge hopper 8 to the charging conveyor 1 are input from the drive control section 15 of the discharge valve 14 to the blast furnace integrated control section 13, where the raw material supply time is calculated.

During the process in which the raw material M is conveyed onto the rotating chute 2 by the charging belt conveyor 1, the raw material position is detected by the raw material detection device 10, and is input to the blast furnace integrated control unit 13 to control the rotation of the rotating chute 2. The start (end) timing is calculated, and based on these calculations and various calculations described later, the swing chute 2, drive control unit 11, and discharge gate valve 7
The swinging of the swing chute 2 or the discharge gate valve 7 is controlled via the drive control section 12 of the swing chute 2 .

Next, the blast furnace general control section (sequencer) 13
An example of arithmetic control will be briefly described below.

This calculation control example is for the case of the calculation control example 1 described above, and the opening degree of the swing chute 2 is initially set so that the opening degree of the swing chute 2 is set within a range where the raw material does not overflow from the swing chute 2 according to the raw material supply amount and the raw material supply time. ,
The number of turns of the turning chute 2 (integer number of turns of grill J degrees), and turning speed are controlled.

About calculation control example 1 Initial setting of swing chute discharge gate valve opening (opening 60% → discharge 2000t/H) Conveyance amount and speed (time) from belt conveyor
The rotation speed is controlled so that the number of rotations is an integer number of "Grill J degrees".

Figure 4 START → Ejection time selection calculation? YES →Gate PRESET selection? YES →Gate PRESET (Do) →Determine Do so that Do > Dmin is usually YES.

Shelf hanging limit...Judgment of blockage limit at Gate (determined experimentally), i.e. trouble prevention → Calculation of qi qi=Ki・Do ^m (m is approximately 2.5): Material discharge speed Ki and index m at the discharge gate valve are It varies depending on the brand, etc., and is determined through experiments or actual reactors.

Calculation of ti = W/qi〓3600 ^(sec) Material conveyed amount W (Ton) ← Weighed value Flow control gate discharge speed qi (T/H) ← From ↓ Is t _B > ti? (sec) t _B : Material discharge time from the belt conveyor to the rotating chute (surge hopper discharge time record) This is normally set to NO for control purposes.
Set it.

↓ Check the overflow conditions The raw material conveyance speed q _B (T/H) is q _B = W/t
_B 〓3600 Rotating discharge speed q _i (T/H) is more than q _i =
W/ti〓3600 Therefore, the raw material deposition rate is (T/H) q _B - q _i = W (1/t _B -1/ti) ^* 3600 Here, if the capacity of the rotating chute is V (design value m ³ ), then , the condition for not overflowing is as ρ density (t/m ³ ) (q _B −q _i )t _B /3600 1/ρ<V From the above equation, ∴W/ρ(1−t _B /ti)<V .

This is also normally set to YES for control purposes.

↓ Calculation of integer turning conditions R (rotation speed) RESET? → Normally NO ↓ From the descriptions of specifications P12 to 13, ni=ti〓Rmax/60 Round off ni to ni′ (integer number of rotations) Determine Ri=60〓ni′/ti<Rmax.

<Calculation example> Ore 2000T/H at 60% gate opening ↓ ti = 26/2000 x 3600 = 46.8 (sec) ↓ Calculating with charging BC capacity of 3000T/H, t _B = 26/3000 x 3600 = 31.2 ( sec) ∴t _B <ti.

↓ W/ρ(1- _tB /ti)<V is 26/1.8(1-31.2/46.8)= ^4.8m3 <1
^0m3 .

Also, Rmax = 9 rpm.

ni=46.8×9/60=7.02 Therefore, it is sufficient to set ni′=7.

The turning speed at this time is Ri=60×7/46.8=8.97<9=Rmax is sufficient.

In this way, the swing conditions of the swing chute 2 are calculated in the blast furnace integrated control section, and the swing conditions of the swing chute 2 are calculated via the drive control section 12 of the drive control section 11 (or the discharge gate valve 7). 7) is controlled.

According to the present invention, in which the number of turns, the turning speed, or the opening degree of the discharge gate valve 7 of the turning chute 2 is controlled in this way, the relay hopper 3, the small bell hopper 4,
The fluctuation width of the raw material accumulation level in the circumferential direction within the large bell hopper 5 is much smaller than that of the conventional example shown in Fig. 6, and as a result, the accuracy of controlling the raw material charging distribution in the blast furnace is greatly improved. , it is easy to approach the optimum conditions for blast furnace operation.

(Effects of the Invention) In the method of the present invention, when raw materials are charged from a belt conveyor into a relay hopper via a rotating chute, the function of the rotating chute is fully demonstrated. It is possible to eliminate unevenness in the directionality and discharge flow rate of the raw material discharged to the bell, and to make the charging distribution of the raw material uniform in the circumferential direction from the rotating chute to the relay hopper. The deposition distribution can be made uniform, and the controllability of the raw material charging distribution in the furnace by the raw material repeller can be improved. It also makes it easier to improve the accuracy of the time schedule for charging raw materials, which brings about excellent effects such as suppressing fluctuations in the amount of Si in the hot metal, stabilizing furnace operation by stabilizing the fingers, and contributing to stabilizing the quality of the hot metal. It is something.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the material charging distribution situation in each part in the furnace top charging by the conventional rotating chute, and Fig. 2 is an explanatory diagram showing the material charging distribution situation in each part in the furnace top material charging by the method of the present invention. An explanatory diagram representing
Figure 3 A, B, and C are explanatory diagrams showing an example of the raw material receiving sequence of the rotating chute in the present invention;
The figure shows the raw material receiving area of the rotating chute in the present invention.
FIG. 5 is a schematic explanatory diagram of an example of an apparatus for implementing the present invention; FIG. 6 is a schematic explanatory diagram showing fluctuations in the accumulation level of the raw material in the large bell hopper in the circumferential direction according to the present invention. It is. 1...Belt conveyor, 2...Swivel chute, 3...Fixed hopper, 4...Small belt hopper, 5...Large bell hopper, 6...Furnace interior, 7...
Discharge gate valve, 8... Surge hopper, 9... Raw material repelling plate, M... Raw material, 10... Raw material detection device,
11...Swivel chute drive control unit, 12...Discharge gate valve drive control unit, 13...Blast furnace integrated control unit,
14...Discharge valve, 15...Discharge valve drive control section.

Claims (1)

[Claims] 1 A bell-type material loading system for a vertical furnace in which raw materials from a belt conveyor are charged into a relay hopper via a rotating chute equipped with a discharge gate valve, and then the bell is opened and charged into the furnace. In the method of charging raw materials to a relay hopper in a feeding device, the brand of raw material (raw material characteristics), the amount of raw material supplied, the supply time, and the capacity value of the rotating chute are grasped in advance during the process in which the raw material is supplied to the rotating chute, The number of turns, rotation speed, and rotation speed of the rotating chute are adjusted so that the supplied raw material is stored in the rotating chute and the raw material discharge rate from the rotating chute to the relay hopper is constant within a range where the raw material does not overflow. A method for charging raw materials into a relay hopper in a bell-type raw material charging device for a vertical furnace, characterized by calculating and controlling the opening degree of a discharge gate valve and controlling the distribution of raw materials in the circumferential direction of the relay hopper.