JPS5934216B2 - How to operate DL sintering machine - Google Patents

Description

[Detailed description of the invention] This invention relates to a method of operating a DL type sintering machine,
In particular, by measuring the air volume passing through the sinter layer, which sensitively reflects the sintering process, the red tropical distribution can be estimated based on the measured air volume, and based on this, the sinter can be controlled to ensure stable sintered ore quality. This is a proposal for a method of operating a sintering machine that is unique in that it performs the following steps.

In general sintering equipment, after charging coke powder and ore powder onto a pallet using a raw material charging device, the surface of the charged raw material layer is ignited, and as sintering progresses from the upper layer to the lower layer, The pallet is directed toward the ore discharge section, and at the same time as the pallet is ignited, the air passing through the raw material layer is sucked from below the pallet via the wind box and the main scavenger. By burning coke, agglomerated sintered ore is produced through the processes of drying, combustion, sintering, and cooling.

To explain this process using Fig. 1, blending tanks 1, ~1
Raw materials 5 such as fine ore, coke, and limestone cut out from the merrick 2 pass through the merrick 2, are injected and mixed in the mixer 3, are stored in the feed hopper 4, and are then transferred to the feeder 6.
It is then loaded onto the pallet 7.

The coke in the raw material layer charged onto the pallet 7 is ignited by the ignition furnace 8 and burned to burn ore powder.

On the other hand, each wind box 10□ ~ under pallet 7
10n, which is connected to the main blower 11.

Since air is sucked into the lower part of the raw material layer through this main blower 11, the red-hot zone (FFP) progresses sequentially from the upper layer to the lower layer of the raw material layer, and when it reaches the vicinity of the ore discharge area, sintering begins. It is set to be completed.

In normal operation of a sintering machine, the point BTP at which sintering is completed is detected from the exhaust gas temperature measurement or exhaust gas component values with a thermocouple installed in the wind box, and the pallet is set so that the BTP point falls within a certain range. It is controlled by adjusting the speed, sintered layer thickness, and main blower suction tamper opening.

When such conventional control methods are adopted, the quality of the produced sintered ore can only be detected by sampling the sintered ore after production. Delays are a major problem.

As explained above, sinter agglomeration is carried out through processes such as drying, combustion sintering, and cooling. When divided,
It is known that the residence time of the raw material in the red-hot zone among these zones, that is, the time during which the raw material is maintained at a high temperature due to coke combustion, has a significant effect on the quality of the sintered mineral product.

Therefore, by adjusting the above-mentioned high temperature holding time, it becomes possible to control the quality of the sintered ore product during the manufacturing process.

However, conventional methods for directly controlling the high temperature holding time have not been used.

In order to measure such high temperature retention time in an actual machine, there is no suitable measurement method other than inserting a thermocouple directly into the sintered layer, and it is difficult to maintain the thermoelectric lamp, making it impossible. This is because it had been done.

Furthermore, it is a well-known fact that the coke sintering rate and cooling rate in the sintered bed are determined by the amount of air passing through the bed, which greatly affects the quality and productivity of the sintered ore.

In this sense, if the amount of air passing through the layer during the sintering process can be detected, the situation within the layer can be detected.

This invention is a method developed to solve the above-mentioned problems of the prior art, and by measuring the amount of air passing through the sintered layer, the red-hot zone distribution is estimated and each sintered raw material is placed in the red-hot zone. By appropriately controlling the residence time in the reactor, the operation was carried out to obtain a predetermined quality of sintered ore, and sintered ore of stable quality was ensured.

The configuration of the present invention will be described in detail below in conjunction with the explanation of the drawings.

FIG. 2 of the drawings schematically shows a device that continuously measures the air flow rate passing through the layer in the machine length direction during the sintering operation process. The cart 13 supports a wind box 14, and this cart 13 moves up and down as well as reciprocates in the longitudinal direction of the pallet 7. During this movement, the sintered layer 15
The amount of air sucked into the air box 14 is configured to immediately determine the amount of air passing through the air box 14 from the suction flow velocity flowing inside the air box 14.

According to this device 12, the amount of air passing through the layer (the amount of air sucked into the layer) in the longitudinal direction of the sintering machine can be accurately measured.

An example of measurements taken by the air volume measuring device 12 is shown in FIG. 3-a.

FIG. 3-a shows a plot of measured values every 30 seconds and an approximate curve thereof.

This measured passing air volume value is based on the ventilation resistance in the sintered layer 15.

Therefore, from the passing air volume distribution obtained by the measurement, the red tropical distribution within the layer in the longitudinal direction of the sintering machine can be determined using the ventilation resistance index of each sintered zone and the passing air volume index.

The first feature of this invention lies in estimating the distribution of the red tropics from this wind volume.

The method for estimating the distribution of the red tropics from the amount of passing wind adopted in the present invention will be described below.

Now, inside the sintered layer, as shown in Figure 6, there is a combustion front (RF
3 by two lines: P) 9 and sintering front (HBP) 16.
The zone is divided into a raw material zone 15a, a red zone 15b, and a sintered zone 15c, respectively.

Still, if the point where the combustion front I (FP9 intersects with the pallet surface is HFPo), equations (1) to (3) hold true, and the widths of each band H□*H2p H3 are respectively (1) to
From equation (3), it is expressed by the following equations (4), (5), and (6).

In other words, the pressure loss of the sintered layer is proportional to the exponential power of the passing air volume, and the pressure loss at any position is expressed by the following formula: ΔP=(R1H□+R2H2+R3H3)G"-...(
1) The layer thickness is H-H1+H2+H3 using the following formula:
(2) The height of RFP is expressed by the following formula.

From the above formulas (1) to (3), the heights H0 to H3 of each sintered zone are expressed by the following formulas.

Mass -H-H, -H2・・・・・・・・・・・・・〈6
) HJ Koki) ΔP: Negative suction pressure at any point in the longitudinal direction (ky/m2) G: Suction air volume at any point in the longitudinal direction (kg/m2・min) θ: Elapsed time from the ore feeding end (min) α: Index dependent on the state of gas flow (laminar flow: α = 1, turbulent flow: α = 2) R1-R3: From the pressure drop resistance coefficient of the raw material zone, red zone, and sintering completion zone, respectively, Air volume G, box pressure ΔP, layer thickness H1 combustion front (
If the point RFPo where HFP) intersects with the pallet surface, the ventilation resistance coefficients R1 to R3 of each zone, and the layer passage air volume index α are known, it is possible to estimate the red tropical distribution in the longitudinal direction of the sintering machine.

In this regard, the HFPo is
It can be detected by the exhaust gas temperature transition measured at 0n.

That is, when the exhaust gas temperature is measured by a thermocouple provided for each wind box 101 to 10n, the R
The exhaust gas temperature remains almost constant until the FP reaches the pallet surface, and the temperature begins to rise just before and after reaching the pallet surface.

Therefore, the HFPo can be determined by determining the point at which the exhaust gas temperature changes and performing correction using the boundary temperature between each of the three divided zones.

As shown in Fig. 4, the HFPo of this invention detects the point at which the temperature reaches 100°C from the exhaust gas temperature pattern measured in the wind boxes 10□ to 10n, and calculates the time from the ore feed end to reach that point. The value obtained by adding a certain value to that value is H
FPo Toshida.

The value (θT) to be added here is determined by the temperature of the red tropics, and is determined in advance by inserting a thermocouple into the sintered layer 15 and measuring the heat pattern. (.

For example, it has been confirmed that the temperature in the layer during the heating process increases approximately linearly as shown in Figure 5, so from this figure, when the boundary temperature is 1000°C, o, 5m1n
was adopted as θ1.

Next, FIG. 3 shows a specific example of the present invention in which the Red Tropical 15b distribution is estimated from the passing air volume distribution using equations (4) to (6).

This figure shows the Red Tropical 15b distribution calculated using the approximate curve of the passing air volume distribution corresponding to Fig. 3-a.

Note that the shaded box in the figure represents the Red Tropical 15b distribution obtained from the simultaneously measured heat patterns.

The two agree well, demonstrating the validity of the red tropics distribution model of the present invention.

In short, by using FIG. 3-b, by cutting the region of the red zone 15b at an arbitrary sintered layer height, the cut portion corresponds to the high temperature retention time at that height.

That is, the average high temperature retention time can be determined from the red zone width (H2) at any position of the sintered strand using the following equation.

Here, HT: Average high temperature holding time (min) H: Sintered layer thickness (→ H2: Red zone width (→ θ: Elapsed time from the strand feeding end (win)) This H
There is a correlation between T and sintered ore product strength (SI) as shown in Figure 7, and a correlation as shown in Figure 8 is also observed between pallet speed coke blending ratio. Therefore, the appropriate HT value that guarantees the target sintered mineral strength (SI) is set in advance from Figure 7, which shows the operational results, and calculated from the passing air volume distribution obtained as described above. By taking the obtained average high temperature holding time HT and controlling the pallet speed etc. so that it falls within the set value range, sintered ore of a predetermined quality can be obtained.

FIG. 9 is a diagram of the control flow.

As shown in FIG. 1, this control method uses data obtained from the air volume measuring device 12 and
Estimating the red tropical distribution from the temperature of n and finding the average high temperature retention time.

By comparing the obtained average high temperature retention time with a preset appropriate range of high temperature retention time, it may be determined whether or not to take an action, and the control may be performed.

Note that the combustion front RFP is not limited to a straight line, but can also be a curved line depending on the amount of passing air.

In addition, the ventilation resistance index R1 to R3 of each band and the index α of passing air volume may be determined by tests or calculations, but in the embodiment of the present invention, ΔP/H-RGα is adopted as the basic formula. The pressure drop equation was calculated at several points along the length of the aircraft.

Example Normal sintering raw material (coke content 4.9%, moisture 6%)
using a layer thickness of 530 mm and a pallet speed of 2.7 m/min.
Sintering operations have begun.

During this sintering operation, the flow rate of passing air through the layer was measured by running an in-layer passing (suction) air flow measuring device in the discharge direction after the ignition furnace.

At this time, HFPo was corrected by setting the red zone boundary temperature to 1000℃ because an increase in exhaust gas temperature was detected at the thermocouple part located at the 15th wind box position in the sintering machine head, and the above passing air volume was calculated as 20.8 m1n. The wind box pressure ΔP corresponding to the measurement time of the measuring device is -21301 mH2O, and that value and the air permeability R1 to R3 of the sintered layer, here 5.65, 24.36, 3. H2 was calculated using 04 (direct), and the average high temperature holding time HT obtained by refining at the above pallet speed was 2.4 m1n.

Since the sintered product quality SI was targeted at 91% or higher, the pallet speed was set at 2.3 m/m based on the relationship shown in Figures 7 and 8.
When the sintering operation was carried out by changing the temperature to 100.degree., the quality SI of the product actually obtained was 91.2%, which was as expected.

As described above, according to the present invention, the following effects can be expected.

That is, since the quality of sintered ore can be estimated online and appropriate actions can be taken quickly, variations in the quality of sintered ore can be reduced and high-quality sintered ore can be obtained.

[Brief explanation of drawings]

Figure 1 of the drawings is a route map of the sintering equipment, Figure 2 is a perspective view of the air flow measuring device passing through the layer, and Figure 3 is the suction air volume (passing air volume) distribution a in the longitudinal direction of the sintering machine and its distribution. A line diagram showing the estimated red tropical distribution, Figure 4 is an exhaust gas temperature distribution diagram, Figure 5 is a diagram showing the relationship between each zone boundary temperature and the correction coefficient θ,
Figure 6 is a diagram of the sintered layer division model, Figure 7 is a diagram showing the relationship between high temperature holding time (HT) and product strength SI, and Figure 8 is a diagram showing the relationship between high temperature holding time (HT) and product strength SI.
The figure is a diagram showing the relationship between pallet speed and average high temperature holding time, and FIG. 9 is a control flow diagram of an embodiment of the present invention.

Claims (1)

[Claims] 1. Measure the airflow passing through the sintered layer in the longitudinal direction using an airflow measurement device movably installed on the sintered layer of the pallet, and estimate the Red Tropical distribution within the sintered layer from the measured airflow passing through the layer. The feature is that the average high temperature retention time is calculated based on the estimated red tropical distribution, and the sintering machine is controlled so that the average high temperature retention time is within a preset appropriate value range determined from the product quality. How to operate a DL sintering machine.