JPH10251766A - Sintering combustion rate control method - Google Patents

Abstract

(57) [Problem] To provide a sintering combustion speed control means capable of shortening a time delay of feedback control for controlling a water injection amount in a mixer and significantly improving controllability. SOLUTION: In a sintering process, a combustion speed (FFS) is calculated from a distance from an ignition furnace calculated from a change in exhaust air temperature of each wind box to a grade reaching position (FFP) of a combustion front, a pallet speed and a raw material layer thickness. )
At the same time, the amount of water injected into the mixer is determined from the raw material air permeability and the raw material moisture value measured at the mixer outlet side of the raw material supply system, and the amount of water injected into the mixer is adjusted so that the combustion rate predicted from the raw material air permeability becomes the target combustion speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for operating a DL type sintering machine, and more particularly, to a method for controlling a burning rate in a thickness direction of a raw material packed bed in order to reduce variation in product quality.

[0002]

2. Description of the Related Art In a sinter ore production process, sintering raw materials such as fine ore, coke, and limestone are granulated in advance in a mixer (mixing granulator) by adding water (water injection) and rolling the raw materials. , Are sent to a sintering machine (DL type) as pseudo particles, and after sintering, become sinter. In this sintering process, the moisture in the sintering raw material is closely related to the burning rate, so that the productivity of the sinter (which is proportional to the burning rate), and furthermore, the sintering such as sinter particle size and cold strength It is an important factor stabilizing ore quality. Therefore, in the production of sinter, it is necessary to appropriately control the moisture in the sintering raw material so that the burning rate is stabilized.

[0003] For example, Japanese Patent Publication No. 55-38413 discloses a pallet such that a combustion rate becomes a predetermined target based on the permeability of a sintering raw material measured before forming a packed bed on a sintering machine pallet. There has been proposed a combustion rate control method for adjusting the raw material water supplied and the bulk of the feed section.
This method is based on a combustion speed calculated from a grade position (FFP) of a combustion front detected from a change in exhaust air temperature of each wind box measured in accordance with the progress of a raw material, a pallet speed and a layer thickness at that time, and an air permeability. And a method for reducing fluctuations in the combustion rate by measuring the air permeability before the raw material forms a packed bed on the pallet and predictively controlling the combustion rate.

[0004]

However, the conventional combustion speed control method described above has the following problems. The control of the water injection amount in the mixer for adjusting the sintering combustion speed to the target value is usually performed by feedback control. In this feedback control, the time Tx from the operation end (water injection position) to the detection end (air permeability measurement device)
Usually takes 30 minutes or more, which is a problem in maintaining controllability. Therefore, it is generally important to shorten Tx as much as possible in order to improve the controllability of the feedback control. However, in the conventional combustion rate control method described above, it is difficult to reduce Tx because the air permeability is measured before the sintering raw material is charged into the sintering machine and before the formation of the packed bed. Further, in the conventional method, since the combustion rate is controlled by using the two factors of the raw material water supplied on the pallet and the bulk of the feed section, the raw material moisture and the bulk of the feed section are controlled. The combustion control becomes unstable due to the dispersion of the measured values.

The present invention has been made to solve such problems of the prior art, and greatly reduces the time delay of feedback control for controlling the amount of water injected by a mixer, thereby significantly improving controllability. It is intended to propose a sintering combustion rate control method that can be improved.

[0006]

According to the present invention, there is provided a method for controlling a sintering combustion speed according to the present invention. In a sintering process, a grade reaching position (FFP) of a combustion front from an ignition furnace calculated from a change in exhaust air temperature of each wind box. To the combustion speed (FFS) from the distance to the pallet and the thickness of the raw material layer. At the same time, the amount of water injected into the mixer is calculated from the raw material air permeability and the raw material moisture value measured at the mixer outlet side of the raw material supply system.
The injection amount of the mixer is adjusted so that the combustion rate predicted from the raw material air permeability becomes a target combustion rate.

[0007] The great arrival position (FFP) of the combustion front, which is the front end of the firing point, can be detected by the transition of the exhaust air temperature of each wind box measured as the raw material progresses.
According to the present invention, the combustion speed (FFS) is sequentially calculated from the FFP detected from the transition of the exhaust air temperature of each wind box, the pallet speed and the layer thickness.

Simultaneously with the timing of obtaining the FFS, the air permeability is measured by a permeability meter installed on the mixer outlet side of the raw material supply system, and the amount of water injected into the mixer is obtained from the measured air permeability and the raw material moisture value. .

Then, the combustion speed predicted from the FFP detected from the change in the exhaust air temperature of each wind box, the FFS calculated from the pallet speed and the layer thickness, and the air permeability of the raw material obtained at the mixer outlet side is the target combustion speed. Adjust mixer water injection rate to achieve speed.

That is, this method uses a combustion speed obtained from a distance from an ignition furnace calculated from a change in the exhaust air temperature of each wind box to a grade reaching position (FFP) of a combustion front, a pallet speed and a raw material layer thickness. (FFS) is related to the air permeability, and the air permeability is measured at the mixer outlet side of the raw material supply system, and the combustion rate is controlled only by the amount of water injected into the mixer. Can be significantly improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram showing the relationship between the FFP and the exhaust air temperature of each window box in an embodiment of the present invention, FIG. 2 is a control flow diagram in one embodiment of the present invention, and FIG. FIG. 4 is an explanatory view showing a method of measuring a raw material air permeability in the above embodiment, FIG. 4 is a diagram showing a relationship between FFS and raw material air permeability in the above embodiment, and FIG. is a diagram showing the relationship, 1 surge hopper, 2 roll feeder 3 feed, 4 sintering machine pallet, 5 ignition _furnace, 6 1 to 6 _n is windbox, 7 Shuhai _{blower, 8} 1 8 _n is a thermocouple, 9 _{1 to} 9 _n are raw material tanks, 10 is a merrick, 11 mixers, 12 is a raw material air permeability measuring device, 13 is an FFP detecting device, 14 is a pallet speed detector, 15 is an FFS detecting device, 16 Is a layer thickness manual setting device, 17 is Water amount calculating unit, 18 is a target combustion rate manually setting device, 19 is a water injection amount controller.

In FIG. 1, a raw material 3 continuously supplied from a surge hopper 1 by a roll feeder 2 is conveyed to a mining section by moving the pallet while forming a packed layer 3-1 on a pallet 4 of a sintering machine. Meanwhile, the surface of the packed bed 3-1 is ignited by the ignition furnace 5. On the other hand, the wind box 6 ₁ to 6 _n is sucked from below the forced packed bed at a constant capacity of the combustion gas by the main exhaust fan 7. During this time, thermocouples 8 ₁ provided for each wind box
Although the exhaust air temperature is measured by a 8 _n, until the combustion front reaches the Great sintering machine pallet 4 exhaust air temperature is substantially constant, exhaust air temperature behind FFP and phase begins to rise .

Next, an embodiment of a specific control method according to the present invention will be described with reference to FIG. The raw material 3 cut out from each of the raw material tanks 9 _{1 to} 9 _n is firstly measured for the total cut-out amount by the merrick 10, and then mixed and added with water by the mixer 11, and is then supplied to the surge hopper 1. As described above, the raw material 3 put into the surge hopper 1
Ore is continuously supplied on the great layer, and is conveyed to a mining part while forming a packed bed 3-1. During this time, the surface of the packed bed is ignited by the ignition furnace 5. Then, the exhaust air temperature by a thermocouple 8 ₁ to 8 _n provided for each wind box 6 ₁ to 6 _n accordance conveyed to Haikou portion is measured.

[0014] In the FFP detector 13 detects the FFP from exhaust air temperature transition measured in each wind box ₆ 1 to 6 _n, the pallet speed and thickness manually setting device measured by the FFP and pallet speed detector 14 The setting data of the layer thickness taken from 16 is input to the FFS detecting device 15,
The combustion speed FFS is obtained from the following equation (1) and is output to the water injection amount calculation device 16.

[0015] W: Layer thickness PS: Pallet speed l (FFP): Distance from ignition furnace to FFP

At the same time as the above timing, the air permeability of the raw material sent to the surge hopper 1 is measured by the raw material air permeability measuring device 12 installed on the outlet side of the mixer 11 in the raw material transporting process, and is output to the water injection amount calculating device 16. .

As shown in FIG. 3, the raw material air permeability measuring device 12 has a structure in which compressed air can be blown from a pipe 12-2 with a flow control valve 12-3 connected to the bottom of the air permeability measuring container 12-1. In addition, a pressure gauge 12-4 and a flow meter 12-5 are attached near the bottom of the air permeability measurement container 12-1. That is, in the present invention, the sampling raw material 3 collected at the belt connecting portion on the outlet side of the mixer 11 is charged into the air permeability measurement container 12-1, and a fixed flow of compressed air is blown from the bottom of the measurement container. At 12-4, the pressure loss of the upper and lower surfaces of the raw material packed layer in the container is measured, and the pressure loss, the thickness of the raw material packed layer in the container, the ventilation volume measured by the flow meter 12-5, and the suction area (the area at the bottom of the container) ), The raw material permeability is determined by the following equation (2).

[0018] J: Air permeability (m ³ / min) A: Suction area (m ² ) h: Layer thickness (m) S: Packed layer pressure loss (mH ₂ O)

The water injection amount calculating device 16 obtains the relationship between the air permeability and the combustion speed FFS as shown in FIG. At this time, the relationship between the FFS and the raw material air permeability is represented by Expression (3).

FFS = A × air permeability J + B Expression (3) A: coefficient B: constant

At the same time, the relationship between the amount of water injected into the mixer and the air permeability J is sequentially accumulated to obtain the relationship as shown in FIG. At this time, the relationship between the amount of water injected into the mixer and the air permeability J is expressed by equation (4).

Air permeability J = A × raw material moisture M + B Equation (4) A: coefficient B: constant

Then, the combustion speed FFS is predicted from the measured raw material air permeability, and the water injection amount for the predicted combustion speed to reach the target combustion speed input from the manual setting device 18 is output to the water injection amount controller 19. , Water is added to the raw material in the mixer 11.

For example, if the combustion speed FFS is 25 mm / mi
When n is maintained, the raw material air permeability 29JPU corresponding to the combustion speed FFS 25 mm / min is obtained from the relationship diagram of the combustion speed FFS and the air permeability shown in FIG. 4, and then the air permeability and the mixer injection amount shown in FIG. From the relation diagram, the raw material permeability 29JP
A mixer injection amount of 6.7 T / H corresponding to U is obtained, and the amount of water added to the mixer is adjusted to 6.7 T / H.

[0025]

FIG. 6 compares the feedback controllability of the present invention and the conventional method in the combustion rate control. FIG. 6 (A) shows the measurement of the air permeability. FIG. 7B shows the transition of the combustion speed when water injection is controlled by the conventional combustion speed control method performed at the point of time, and FIG. 7B shows the transition of combustion speed when water injection is controlled by the combustion speed control method of the present invention.

That is, while the material transfer time (time delay Tx) from the mixer injection position to the air permeability measuring device is usually about 30 minutes in the conventional method, it is only 3 minutes in the method of the present invention. The controllability can be significantly improved by greatly reducing the time delay, and as a result, FIG.
As is clear from the data of (A) and (B), the variation of the burning rate can be greatly reduced to 2.88 mm / min in the method (B) of the present invention, compared with 5.89 mm / min in the conventional method (A). The superiority of the present invention was confirmed.

[0027]

As described above, according to the method of the present invention, the air permeability of the raw material is measured on the outlet side of the mixer of the raw material supply system.
By controlling the combustion rate only with the amount of water injected into the mixer,
Since the time delay of the feedback control is small and the controllability can be remarkably improved, it has a great effect on stabilizing the product quality and productivity of the sintered ore.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a relationship between a combustion speed FFP and an exhaust air temperature of each wind box in an embodiment of the present invention.

FIG. 2 is a control flow chart in one embodiment of the present invention.

FIG. 3 is an explanatory view showing a method of measuring a raw material air permeability in the embodiment.

FIG. 4 is a diagram showing a relationship between FFS and raw material air permeability in the embodiment.

FIG. 5 is a diagram showing a relationship between a raw material air permeability and a mixer water injection amount in the above embodiment.

FIG. 6 is a graph comparing the feedback controllability in the combustion rate control of the present invention and the conventional method. FIG. 6 (A) shows the measurement of the air permeability at the time before the formation of the packed bed in which the sintering raw material was charged into the sintering machine. FIG. 7B shows a transition of the combustion speed when water injection is controlled by a conventional combustion speed control method to be performed, and FIG. 7B shows a transition of combustion speed when water injection is controlled by the combustion speed control method of the present invention.

[Explanation of symbols]

1 surge hopper 2 roll feeder 3 feed 4 sintering machine pallet 5 ignition furnace 6 ₁ to 6 _n windbox 7 main exhauster 8 ₁ to 8 _n thermocouple 9 ₁ to 9 _n material tank 10 Merrick 11 mixer 12 the raw material air permeability measuring apparatus 13 FFP detector 14 Pallet speed detector 15 FFS detector 16 Layer thickness manual setting device 17 Water injection amount calculation device 18 Target combustion speed manual setting device 19 Water injection amount controller

Claims (1)

[Claims] In the sintering process, the combustion speed (from the distance from the ignition furnace calculated from the transition of the exhaust air temperature of each wind box to the grade reaching position (FFP) of the combustion front), the pallet speed and the thickness of the raw material layer, is determined. FFS)
Simultaneously, the mixer water injection amount is obtained from the raw material air permeability and the raw material moisture value measured at the mixer outlet side of the raw material supply system, and the mixer water injection amount is adjusted so that the combustion rate predicted from the raw material air permeability becomes the target combustion rate. A sintering combustion rate control method characterized by the following.