JPS6115930A - Method for controlling water of sintered material - Google Patents

Abstract

PURPOSE:To control precisely the water and to obtain sintered ore of stabilized quality by arranging an infrared water-content meter on the upstream side of a granulation mixer and a neutron water-content meter on the downstream side, and feeding a specified amt. of water based on the measured value into the granulation mixer. CONSTITUTION:A specified amt. of a sintered material is brought out onto a belt conveyor 3, weighed by a meter 4, and introduced into the first granulation mixer 10. The amt. of water to be injected is controlled by a water flow regulator 13 with the output signal from a controller 5. When the material is supplied into the second granulation mixer 20, the water content in the sintered material is measured with an infrared water-content meter 30a, and outputted to controllers 5 and 6. The output signal is outputted from the controller 6 to a washing water supply regulator 23 to regulate the amt. of water to be injected, and granulation is carried out. Then the sintered material is charged into a material surge hopper 41 of a sintering machine 40. The water content is measured with a neutron water-content meter 42a, and outputted to the controller 6 through a water-content meter transducing part 42b. The amt. of water to be injected is controlled along with the desired water-content value of a desired water- content setting device 7 through the controllers 5 and 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for controlling the moisture content of sintered raw materials in order to produce sintered ore of stable quality.

(Prior art) Sintered ore, which is the main raw material charged into a blast furnace, is manufactured by firing sintered raw materials such as fine ore in sintering equipment, and the sintered raw materials are sintered while ensuring air permeability. In order to improve the productivity of the equipment and stabilize the quality of the sintered ore, it is made into pseudo-granules and coarsened.

To achieve this pseudo-granulation, it is important to contain an appropriate amount of moisture in the sintering raw material supplied to the sintering equipment, and for this reason, the sintering equipment generally includes mixing and granulation equipment before the sintering machine. It is installed here, and moisture management is carried out here.

Now, regarding the operation details of the sintering equipment, as shown in FIG. Mixer 10. Water is injected into the second granulation mixer 20, where the material is pseudo-granulated and coarsened, and then charged into the raw material surge hopper 41 of the sintering machine 40.Then, the sintered raw material cut out from here is sent to the sintering machine 40. It is fired and becomes sintered ore.

In the above-mentioned granulation mixer, water injection amount control is performed in order to adjust the moisture content of the sintering raw material to an appropriate amount, and the water injection amount control is roughly divided into a neutron moisture meter method and an infrared moisture meter method.

The former neutron moisture meter method measures the moisture in the raw material with a neutron moisture meter 42 attached to the raw material surge hopper 41 shown in FIG. is adjusted to control the amount of water poured into the second granulation mixer 20. However, with this method, there was a delay in response to the moisture content of the target raw material, and the moisture content in the sintered raw material could not be adequately adjusted. This is because the distance between the moisture measurement position and the water injection position is long, and specifically, the mixing residence time in the granulation mixer is about 1 to 4 minutes, and the heating from the granulation mixer to the raw material surge hopper is due to The transportation time is approximately 0.5 to 2 minutes, and the residence time of the raw material to the detection position of the neutron moisture needle in the raw material surge hopper is approximately 1 to 2 minutes (IJ). This is because a time constant of approximately 0.5 to 1 minute is required.

The latter infrared moisture meter method uses an infrared moisture meter 30 placed after the second granulation mixer 20 as shown in Fig. 3 to measure the moisture in the raw material, and determines the moisture content based on this measured value. The amount of water injected into the second granulation mixer 20 is controlled by adjusting the opening degree of the valve 21 so that the amount of water reaches the specified value.

Unlike the neutron moisture meter method, this method does not have a delay in control, but there are problems with the measurement accuracy of the infrared moisture meter, control details, etc. In other words, when measuring, infrared moisture meters are affected by the grain size of the sintered raw material, external light such as sunlight, etc.For example, the infrared moisture meter is affected by changes in the blending ratio of each raw material brand, color changes due to changes in the amount of water poured, etc. This caused a measurement error, which made it impossible to adjust the moisture content to the target value.

In addition, since the infrared moisture meter is affected by the surface properties of the sintered raw materials stacked in layers, changes in the measurement distance, etc., the scraper plate 9 (
(shown in Fig. 3) is provided to level the height, but when the sintered raw material is scraped by the scraping plate, the sintered raw material that has already been pseudogranulated by the second granulation mixer 20 is There was a problem in that the parts were crushed and the air permeability deteriorated.

Furthermore, in the case of this method, since the measurement position is on the upstream side, it is difficult to grasp the amount of water that evaporates until the injected sintering raw material is supplied to the sintering machine 40. It was difficult to match the moisture content in the raw materials to the target value.

Note that JP-A-58-31'038 has been proposed in order to eliminate the measurement error of an infrared moisture meter due to the color, particle size, etc. of the sintered raw material mentioned above, but this method cannot eliminate measurement errors. However, other issues could not be resolved.

〔the purpose〕

The present invention has been made in view of the above circumstances, and its purpose is to eliminate control delays and reduce water content in the sintered raw materials by performing feedforward control and feedback control of water injection into the sintered raw materials. An object of the present invention is to provide a method for controlling moisture in sintered raw materials with high adjustment accuracy.

[Structure of the invention]

The method for controlling the moisture content of a sintered raw material according to the present invention is a method for controlling the moisture content of a sintered raw material to a target moisture content in a sintering equipment equipped with a granulation mixer. An infrared moisture meter is placed upstream of the granulation mixer that injects water to measure the moisture content, and based on the measured value, the amount of water injected into the granulation mixer is feedforward controlled. A neutron moisture needle is placed on the side to measure moisture, and based on the measured value, the amount of water injected into the granulation mixer is feedback-controlled, and the above-mentioned feedforward control system-1 correction is added. .

〔Example〕

The present invention will be specifically explained below based on the drawings.

FIG. 1 is a schematic diagram showing the implementation state of the present invention, and in the figure 1
indicates mixed granulation equipment. The raw material tank 2 is arranged upstream of the mixing and granulation equipment 1, and the sintering raw material is stored in this tank. is moved in the direction of the mark.

A weighing scale 4 is installed downstream of the raw material tank 2.
The weight of the sintered raw material on the belt conveyor 3 is measured and introduced into the first granulation mixer 10. Heavy it/l
! The lJ constant value is given to the first granulation mixer controller 5 and the second granulation mixer controller 6.

The sintering raw material introduced into the first granulation mixer 10 is injected with water here. At this time, the water flow W regulator 13 adjusts the opening degree of the valve 11 based on the output signal from the controller 5, and the amount of water based on this opening degree is supplied to the first granulation mixer 10 through the valve 11. . Further, a foot bank signal from a flow meter 12 installed on the water source (not shown) side of the valve 11 is inputted to the water flow rate regulator 13. Controller 5 outside
The measurement signal is output to. and the first granulation mixer 1
The sintering raw material injected with water at 0 is sent to the second granulation mixer 20.

An infrared moisture meter 30a is installed between the first granulation mixer 10 and the second granulation mixer 20 at a position facing the sintering raw material. The water content in the coagulating material is measured, and the measurement signal is converted into an electrical signal related to the water content by the moisture meter converter 30b and output to the controllers 5 and 6.

After the moisture content is measured, the sintering raw material is transferred to the second granulation mixer 20.
^、It is introduced and further water is poured here. At this time, the water flow rate regulator 23 adjusts the opening degree of the valve 21 based on the output signal of the controller 6, and the amount of water based on this opening degree is supplied to the second granulation mixer 20 through the valve 21. Further, a feedback signal from a flow meter 22 attached to the water source (not shown) side of the valve 21 is input to the water flow rate regulator 23 and the controller 6.

The sintering raw material injected with water in the second granulation mixer 20 is charged into the raw material surge hopper 41 of the sintering machine 40.

The measurement flow of the neutron moisture meter 42a is inserted into the raw material surge hopper 41, and the neutron moisture meter 42a
The moisture in the sintered raw material in the raw material surge hopper 41 measured in step a is converted into an electrical signal related to the moisture content by the moisture meter converter 42b and output to the second granulation mixer controller 6.

The controller 5 and the controller 6 each receive a target moisture value from the target moisture setting device 7, for example, the controller 6 receives a final target moisture value, and the controller 5 receives a signal regarding a moisture value slightly less than the final target moisture. The controller 5 has a weighing scale 4. The amount of water injected in the first granulation mixer lo is calculated from each input signal from the moisture meter conversion unit 30b and the signal of the target moisture value based on the moisture control content described below, and the calculated signal is sent to the water flow rate regulator 13. Output to.

On the other hand, the controller 6 controls the weighing scale 4. The amount of water injected in the second granulation mixer 20 is calculated based on the input signals from the moisture meter converters 30b and 42b and the target moisture value signal from the target moisture setting device 7, based on the moisture control content described below. , and sends the calculated signal to the water flow rate regulator 23.

The water flow regulators 13 and 23 each receive an input signal and a flow meter 12.
, 22, the opening degree of the valve II, 21 is controlled based on the feed hack signal regarding the water flow rate from the valves II, 22.

The content of moisture control in the sintering equipment configured as described above, ie, the mixing granulation equipment and the sintering machine, will be explained.

Loading of sintering raw materials being transferred at a predetermined speed on the heald conveyor 3 using a weighing scale 4 @feed rate (Wet, t/h)
is measured. Further, the moisture m1 in the sintering raw material injected with water in the first granulation mixer 10 is measured by an infrared moisture meter 30a.

Now, at this time, W, ml, the measured value f1 of the flow meter 12, the target, and the amount of water F+ required to reach the target moisture value M1 are determined by the following equation (1).

F1=KI-f++(14+) ・W(K2 ・(M
I-m(1)+(142) ・(MI-m+) )・
... (1) However, mo: Moisture contained in the sintered raw material before water is poured, 2: Constant This (Equation 11 is set in advance to the controller 5. Moisture meter converter 30b etc. When the ml, Wl, f1.Ml signal is inputted, the controller 5 calculates Fl.Then, the controller 5 outputs a signal related to this water flow rate to the water flow rate regulator 13, and outputs the signal related to the water flow rate to the first granulation mixer. The water injection amount of 10 is controlled by feed bank.

Note that W and mo are trunked according to the speed of the belt conveyor, and are calculated using values that match the timing when passing through the first granulation mixer.

Furthermore, if the value of mo cannot be determined in advance, 2 may be set to zero.

On the other hand, the controller 6 indicates the water injection amount F in the second granulation mixer 20.
The following equation (2) regarding 2 is set in advance, and F2-
to 3 ・ f2+ (1- to 3) HW (town-
(n+1 +α) ) -121 However, F3
: Constant -12 Measured value of two flowmeters 22 Signals from moisture meter converter 30b etc. ml, W, f
2 and the target moisture value M2. Note (2)
In the formula, W and the water injection amount F2 are values tracked in accordance with the timing when passing through the second granulation mixer.

Here, α in equation (2) is the corrected moisture value obtained as follows based on the final target moisture value M2 and the moisture measurement value m2 of the neutron moisture meter 42a, and the measurement error of the infrared moisture meter and the neutron of the raw material surge hopper 42. This is a correction valve for water loss due to evaporation etc. up to the measurement position of the moisture meter 42a.

When 1m2-M21≧β, α=m2-M2mm2 M2
When l<β, α-0 1m2-M2 l is the average value of the set time t (seconds), and β is a predetermined constant.

Then, the controller 6 outputs a signal regarding this water flow rate to the water flow rate regulator 23, and feedforward controls the water injection amount of the second granulation mixer 20.

This eliminates the influence of water loss due to evaporation, etc., and the sintered raw material whose moisture content has reached the final target moisture value is fired in the sintering machine 40 to become sintered ore with stable quality.

In the above explanation, the amount of water injected in the first granulation mixer is feed-hack controlled based on the moisture value measured by an infrared moisture meter, but the present invention is not limited to this case, and the amount of water injected in the first granulation mixer is It can be carried out even if it is constant.

Further, the present invention can be carried out even when water is poured into one of the granulation mixers instead of being poured into the second granulation mixer. In this case, the moisture content in the sintering raw material can be adjusted to the target value by performing feedforward control based on the measured value with the infrared moisture meter and by performing feedback control based on the measured value with the neutron moisture meter.

〔effect〕

As described in detail above, the present invention performs feedforward control and feedback control based on the measured values of the infrared moisture needle and the neutron moisture meter, respectively, so that the control delay that occurs in the case of control using only the conventional neutron moisture meter can be avoided. This color can be solved by changing the raw material formulation when controlled only by conventional infrared moisture needles.

It is possible to improve poor control caused by changes in particle size, fluctuations in measurement distance, and water loss due to evaporation, etc., and moisture control is possible through feedback control based on the measured value of neutron moisture δ0, which allows for highly accurate sintering. Moisture in the raw material can be controlled to a target value, making it possible to produce sintered ore with stable quality. Furthermore, the present invention, which does not use a scraper plate for infrared moisture measurement after the final granulation step, produces equivalent effects without deteriorating air permeability.

Furthermore, the present invention has the advantage that even if either the infrared moisture needle or the neutron moisture meter breaks down, water injection can be immediately controlled by one of the moisture meters.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the implementation state of the present invention, Fig. 2, Fig. 3
The figure is an explanatory diagram of the prior art. 1...Mixing granulation equipment 20...Second granulation mixer 3
0a... Infrared moisture meter 40... Sintering machine 42a.
...Neutron moisture meter

Claims (1)

[Claims] 1. A granulation mixer that injects water to bring the moisture content of the sintering raw material to the final target moisture content in a method for controlling the moisture content of the sintering raw material to the target moisture content in a sintering equipment equipped with a granulation mixer. An infrared moisture meter is installed on the upstream side of the granulation mixer to measure the moisture content, and based on the measured value, the amount of water injected into the granulation mixer is feed-forward controlled, and a neutron moisture meter is installed on the downstream side of the granulation mixer. A method for controlling moisture content in a sintered raw material, characterized in that the water content is measured using a sintered raw material, and the amount of water injected into a granulation mixer is feedback-controlled based on the measured value.