JPS60157406A - Control method for level of ore supply hopper - Google Patents

Abstract

PURPOSE:To stabilize the level of an ore supply hopper at a level near the upper limit by adding an in-and-out balance quantity of raw material to an intermittent discharge quantity of an ore supply hopper when the in-and-out balance quantity of raw material in the hopper exceeds a specified value, and supplying only the intermittent discharge quantity of raw material when the in-and-out balance quantity is below the specified value to control the intermittent discharge quantity of raw material from a mixing tank to a transport conveyer. CONSTITUTION:The in-and-out balance quantity of raw material in an ore supply hopper 4 is calculated as a required storage quantity depending upon a difference between the intermittent discharge quantity from the ore supply hopper 4 and the quantity of raw material supplied to the ore supply hopper and upon a difference between the preset value and a measured value of an ore supply hopper level. When the in-and-out balance quantity exceeds a specified valve, an in-and-out balance quantity of raw material is added to the intermittent discharge quantity of the ore supply hopper 4 to control the quantity of raw material supplied from mixing tanks 11-1n to a transport conveyer. When the in-and-out balance quantity is below the specified value, the quantity of raw material supplied from the mixing tanks 11-1n to the transport conveyer is controlled according to only the intermittent discharge quantity of the ore supply hopper 4, so that the ore supply hopper level is stabilized approximately at the upper limit.

Description

[Detailed Description of the Invention] The present invention relates to an ore feed hopper level control method, and in detail,
The present invention relates to ore feed hopper level control that allows stable sintered ore quality to be obtained by stably maintaining the ore feed hopper level, which is a cause of segregation in raw material charging.

In general sintering equipment, the process up to charging raw materials into the sintering machine will be explained using FIG. 1 as follows.

Mixture 1g1. Powdered ore cut from ~1n, coke,
Lime and the like are mixed by water injection in a mixer 3 through a 1 m container 2, and after being granulated, they are transported to an ore feed hopper 4. A drum feeder 5 is installed at the lower end of the ore feed hopper 4, and the mixed raw material 8 cut out from the drum feeder 5 is charged into a sintering machine 7 via a chute 6. In sintering fi7, the thickness of the raw material is adjusted using a cut plate, the upper part of the feed layer is ignited by the ignition furnace 10, and sintered in the usual manner.

In normal operations, the level of the ore feed hopper 4 is always adjusted to keep it stable at a high level.
There are two main reasons for this.

(1) As the hopper level changes, the particle size of the blended raw materials cut out from the ore feed hopper changes, which causes uneven ventilation throughout the sintering machine and promotes variations in sintered ore quality. .

(2) If the hopper level is kept at a low level, the sintering machine will have to be stopped immediately due to the stoppage of the raw material system, which will cause a large disturbance to the sintering operation.

Therefore, it is very important to keep the ore hopper level high and stable, and operators strive to do this day and night.

However, when controlling the ore hopper level in this manner, there are the following problems.

First, when adjusting manually, the layer thickness, pallet speed,
There are fluctuations in the cut amount due to changes in the cut amount, and there are also stoppages in the raw material transportation system (gold inspection, CFW cutting abnormality), and changes in the transportation amount, which occur during normal sintering operations. , may occur several dozen times a day, and each time the operator calculates or intuitively adjusts the mixing tank 1,
~ Kiridashi Village from I11 (hereinafter referred to as total transportation volume 5;)
We are trying to stabilize the hopper level in a short time by changing the hopper level. These tasks occupy a large portion of the traditional operator's work, and if cleaning is completely automated, the operator's workload will be reduced all at once.

Next, when the ore feed hopper level is controlled as described above, in the conventional example, the amount Win that will enter the ore feed hopper within a certain period from the current time cannot be accurately determined. A method is used to compare the Lpv and correct the difference.

However, with this method, it is difficult to stabilize the level close to the upper limit in a short period of time (1 to 2 hours).
As shown in Figure (a), it is almost impossible. In addition, FIG. 2(a) is a flowchart 1 for adjusting to the target level in a short time, and the horizontal axis shows the elapsed time (hours) since restarting the raw material system. ), the symbol (a) indicates the stop of the raw material system, and the symbol (b) indicates the restart of the raw material system.

However, the transport line from the blending tank to the ore feed hopper is long, and this transportation system has a large amount of dead time, in which there is a time delay before actions to increase or decrease the amount of raw material cut out from the blending tank affect the ore feed hopper level. (approximately 10 minutes) and the capacity of the feeding hopper is small (it becomes a ditch tank in about 10 minutes), so in order to reach the target level in a short time, the mixing tank cutting amount was increased, and the target level was reached. Until this point is reached, the total amount of raw materials transported will be enormous. Even if the ore hopper needle wheel exceeds the target level and the required total transport volume decreases, the above action will still continue to have a high total transport volume on the raw material system belt, so the subsequent ore hopper level will decrease. During control, the hopper level immediately reaches the upper limit and the raw material system stops.

Therefore, as shown in FIG. 2(a), if the raw material system is repeatedly started and stopped, the hopper level will greatly hunt, and the hopper level will change from the upper limit to the lower limit, and no stability will be obtained. In addition, in order to avoid such a situation, it is necessary to make the amount of correction by Lsv and Lpv extremely small, but with this control, as shown in Fig. 2 (b
As shown in Figure 1, it takes a long time (8 to 1
0 hours) and causes many problems. In addition, FIG. 2(b) is a flowchart when the control is made gentle, and like FIG. 2(a), the symbol (a) indicates the stop of the raw material system, and the symbol (b) indicates the restart of the raw material system. show.

Recently, as one of the hopper level control methods, the amount of raw material cut out from the raw material mixing tank and charged into the hopper via the conveyor, the weight of the raw material in the hopper, and the weight of the raw material from the hopper to the sintering machine. A method has been proposed for predictively controlling the amount of raw material cut out from the blending tank.

In this control method, the amount of raw material cut out from the hopper has conventionally been calculated based on the raw material density determined from the measured values of an air permeability meter and a weighing scale installed below the cut-out part of the hopper, and the raw material loading thickness on the sintering machine strand. The whale method is used, which calculates from the width and strand movement speed.

However, in the method of determining the raw material density from the measured values of a permeability meter and a weighing scale, maintenance of the equipment is difficult because the measuring equipment is installed below the cutout of the hopper.
Therefore, from a long-term perspective, there is also a problem in terms of measurement frequency.

The present invention aims to solve these problems,
Specifically, the ore feed hopper level is stabilized at a level close to the upper limit in a short period of time, thereby shortening the time during which the permeability of the entire sintering machine becomes uneven, and furthermore, the sintering machine due to the stoppage of the raw material system. We propose a control method that minimizes the risk of stoppage and, as a result, reduces the variation in sinter quality.

The method of the present invention will be explained in detail below.

First, in the raw material supply system, measure the raw material supply volume Win to be supplied to the ore feed hopper 4 within a certain period of time from the current time and the amount vJout of the blended raw material cut out from the ore feed hopper 4, and set the current hopper level setting value Lsv. , the actual measured value is Lpv, the balance of raw materials in the ore feed hopper 4 △W is as follows (
1) It can be determined by the formula.

△Vl=(lout-Win)+kt (Lsv-Lp
v)...-(1, where k is a constant.

Normally, it is sufficient to send an amount equivalent to this income and expenditure balance ΔW to the ore feed hopper 4, but the raw material supply system that supplies this material is long as described above, and there is a time delay before it affects the ore feed hopper level. This leads to level hunting on the ore supply hopper side.

Therefore, the total transportation I W T is controlled by comparing the raw material balance amount ΔW with 2 to a predetermined value. That is, if the predetermined value exceeds 2, the raw material supply [IWin to total transport II w T is controlled to the value obtained by adding the balance amount ΔW to the cutout 1lWout of the ore feed hopper, and if it is smaller than the predetermined value by 2, the ore feed The raw material supply amount W i +1 to the total transportation Pa w T are controlled based on the cut-out two out from the hopper.

To show the relationship more specifically, when △w > k 2, W, = Wout(α+o, 5)+ has 3xΔL・−・・
-(2) When △W<k2, W□-Wout(α+0,5)・・・・・・・・・・・・
・・・・・・・・・・・・(3) However, WT is the total transportation volume,
k3 is a constant (0<k3<1). Note that in equations (2) and (3), te α is a value determined from Lsv and Lpv, and has a relationship of 0 x α<1, but α is a predetermined value. The value is based on 4, and it is changed when △W<k4, and 8W>
There is no change at k4.

By controlling the transportation amount of raw materials in this way, the transportation amount is always controlled toward a predetermined value of 2, and the raw materials are not excessively supplied to the feeding hopper or cut out, so hopper level control is It can be achieved stably and in a short period of time.

That is, when the raw material balance amount ΔW exceeds a predetermined value of 2, for example, when the thickness or pallet speed is changed significantly, or when the raw material supply system is stopped for metal detection, etc. It is possible to quickly recover the ore hopper level by taking into consideration the income and expenditure balance amount ΔW and correcting it accordingly. In this case, if we add 100% to the income and expenditure balance amount ΔW,
This tends to cause hunting, and therefore, in actual adjustment, 3 is set to an appropriate value between 0 and 1 according to equation (2). On the other hand, the income and expenditure balance amount ΔW is less than the predetermined value 1 or 2.
When it is smaller, the total transport amount is determined based on only 1 wout cut from the ore feeding hopper, as in equation (3).

Therefore, when controlled by this method, the hopper level reaches the target level in a short time, and the level is stabilized without significant hunting.

Further, the hopper level can be easily and quickly controlled as described above using the W control device shown in FIGS. 3(a) and 3(b).

That is, as shown in Fig. 3(a), the charging amount (in) is calculated from the total transport amount W□ and the water injection amount, and the sintering machine speed, cut plate position, sintering machine, charging density, bedding The cutting height Wout of the ore feed hopper 4 is calculated from the layer thickness. Furthermore, the income and expenditure balance mΔW=(Wout-Win)+kt(L
sv-Lpv) at a period of several seconds.

Depending on whether this ΔW is larger than a predetermined value of 2, the calculation method for the total transport ■W□ is changed (here, P is set to 0 or 1 for illustration) to bring the hopper level to the target level in a short time. It raises and stabilizes. An example of a control device in this case is as shown in FIG. 3(b).
The weight of the raw material on the raw material supply system, that is, the total transportation ffi W T is calculated using the signal from the device 11, and the signal from the device 11 is sent to the calculation device 12 of the hopper supply J[in.

In addition, this supply amount calculation device 12 calculates the hopper supply amount (Wi
n) and sends it to the hopper balance calculation device 13. Similarly, the hopper level measuring device 14 transmits a hopper level signal to the hopper internal balance calculation device 13, and the cutout iiwout of the hopper 4 is calculated from the bedding ore supply hopper 4a.
The cutting amount is calculated by the cutting amount calculation device 15 based on the cutting amount m, the set thickness of the cut plate 9a, and the speed of the sintering machine 7.

In addition, as shown by the broken line in the figure, the cutting amount may be detected using the signal from the drum feeder 5 of the hopper 4, or the signal sent from the cutting amount control device 16 may be received. The calculation result of the hopper balance calculation device 13 is input to the transportation amount control device 17, and the control device 17 controls the mixing ratio control device 18 and cut-out amount control device @19 of the mixing tank 1. The cutting depth of step 1 is controlled to reach a predetermined amount of raw material transported. Note that 2o is a water injection amount control device.

In addition, Fig. 4(a) and (bl) show the process until the level stabilizes after restarting the raw material supply system in the case of control as shown in Fig. 3(a) and (bl) and in the case of manual control.
b). Figure 4(a) is similar to Figures 3(a) and (1).
1), and Figure 4(b) shows manual control, but the time it takes to stabilize is manual 1 hour 2.
Level control is slightly longer at 1 hour and 40 minutes compared to 5 minutes,
According to the present invention, there is not much difference whether manual or level control is used (However, in Fig. 4 (a) and (b), (a) indicates the stop of the raw material supply system, and (b) indicates the restart). .

Also, when comparing the level control in Figures 3(a) and (b) with manual control when the level is stable, Figure 5(
It was as shown in a) and (b). FIG. 5(a) shows level control, and FIG. 5(b) shows manual control. In this case, it can be seen that level control is far superior to manual control.

Incidentally, the number of times the operator takes action is about once every 10 minutes when the level changes significantly, and about once every hour when the level is stable.

The constants used in the level control shown in Figure 4 (a) and Figure 5 (al) are kl = 1.2, k2 = 24
tons/hour, k3=-0.3, k4=42 tons/hour.

[Brief explanation of the drawing]

Figure 1 is a flow sheet of the raw material supply system of the sintering equipment, and Figures 2 (a) and (b) show the elapsed time until stabilization for a short time and slowly for a long time when controlling the hopper level using the conventional example. Each graph, Figure 3 (a) and (b) is a flow sheet of an example of level control implementing the method of the present invention and a diagram of the principle of the control device, and Figure 4 (a) and (b) are graphs showing large changes in level. Each graph showing the elapsed time until level control by the time control device and manual control is stabilized, Figure 5 (a)
) and (b) are graphs showing the elapsed time until level control is stabilized by the control device and manually when the level is stable. Code 1. ~1n...Blending tank 2...Measurer 3...Mixer 4...Ore supply hopper 4a...Bed ore supply hopper 5 ...Drum feeder 6...Chute 7...Sintering machine 8...Blended raw materials 9...
...Cut plate 1o...Ignition furnace 11.
... Chute raw material calculation device 12 ... Charge amount calculation device 13 ... Hopper balance calculation device 14.
... Hopper level measuring device 15 ... Cutting amount calculation device 16 ... Cutting amount control device 17 ... Transport amount control device 18 ... Blending Ratio control device 19 ... Cutting amount control device 20 ... Water injection amount control device Patent applicant Kawasaki Steel Corporation Agent Patent attorney Yoshikatsu Matsushita Attorney Fumio Soejima II Fig. 2 ( α) Fig. 2 (b) l-button restarting force/ra's shoe elongation (time) Fig. 4 (α) Sliding thread I restarting force's thread length (time) ffi≧1 Fig.
(b) Original Pl.

Claims (1)

[Claims] The raw materials are supplied from the raw material blending tank to a conveyor, mixed on this conveyor, and then supplied to an ore feed hopper.Then, the raw materials are fed from this ore feed hopper to a sintering equipment that cuts the blended raw materials to a sintering machine. When controlling the level to keep the raw material charging level of the ore hopper at the set value, if there is a difference between the amount cut from the ore feed hopper and the amount of raw material supplied to the ore feed hopper, the set value and the actual value of the ore feed hopper level are determined. Based on the difference between The amount of raw material supplied from the blending tank to the conveyor is controlled by adding the balance amount, and if the balance balance value is less than a predetermined value,
A method for controlling the level of an ore feed hopper, characterized in that the amount of raw material cut out from the blending tank to the conveyor is controlled based only on the cut amount of the ore feed hopper.