JPS586898B2 - Temperature detection method of sintered raw material layer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting the temperature of a sintered raw material layer on a pallet in a moving grate type sintering machine (hereinafter referred to as DL sintering machine).

As is well known, in modern iron metallurgy, powders such as iron ore lime and coke are kneaded with an appropriate moisture content, and the sintered raw materials are made into coagulated granules and sintered using a DL sintering machine. The condensed ore is used as the main raw material.

In the method of sintering iron ore in the aforementioned DL sintering machine, sintering must be performed in accordance with standards in order to obtain high-quality sintered ore that has sufficient crushing strength even at high temperatures, is difficult to powder, and maintains high air permeability. It is necessary to constantly monitor whether the firing is progressing properly and to appropriately control firing.

For example, in a DL sintering machine, if the pallet movement speed is too fast, sintering will be insufficient.

In other words, since the sintering reaction does not proceed sufficiently to the lower layer of the bed, the yield decreases and the resulting product has low drop strength.

On the other hand, if the moving speed of the pallet is too slow, the sintering reaction will be sufficient, but oxidation will proceed too much and the reduction powdering index will deteriorate.

In other words, productivity will drop significantly.

As mentioned above, even if we consider only the pallet moving speed as one condition for proper firing, the air permeability of the bed will change depending on the state of the different raw material compositions, so the optimal value of the pallet moving speed should be determined accordingly. also changes.

That is, in normal operations, the raw material composition, moisture content, degree of filling of raw materials, etc. constantly change, so it is necessary to change the moving speed of the pallet accordingly.

In other words, it is required to maintain the firing rate at a value determined from past technical experience, but since there is no suitable index for determining the firing rate, conventionally the sinter cake fracture surface in the ore discharge area was Methods such as making judgments based on observation results, such as the shape, thickness, and brightness of the combustion zone, and operating so that the exhaust gas temperature distribution in the latter half of the strand is constant have been adopted.

That is, at present, there is no means to directly monitor the progress of firing and the suitability or unsuitability of the firing speed online and to provide effective information for firing control.

Therefore, the present inventors researched a method of directly detecting the progress of firing, and as a result, developed the method of the present invention.The gist of the present invention is to Insert a heat-resistant cylinder with an open end, then insert a temperature detection end into the cylinder so that it can move up and down, and measure the temperature of any part of the cylinder continuously or intermittently to measure the vertical direction of the raw material layer. The present invention provides a method for detecting temperature of a sintered raw material layer, which is characterized by indirectly measuring temperature or temperature distribution in a direction.

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

Figure 1 shows a well-known DL used to implement the present invention.
This figure shows a schematic diagram of the sintering machine, in which 1 is a sprocket wheel, 2 is a pallet, 3 is a bedding supply device, 4 is a sintering raw material supply device, 5 is an ignition furnace 6 is a bedding layer, and 7 is an unused bedding layer. sintered layer,
Reference numeral 8 indicates a layer in progress of firing, that is, a combustion zone, and reference numeral 9 indicates a layer in which firing has been completed, that is, a sintered layer.

For convenience of explanation, a part of the pallet 2 is omitted and not shown, but the pallet 2 is normally attached to the sprocket wheel 1.
It is moved at a speed of 1 to 5 m/min.

The layer thickness of the sintered raw material on the pallet 2 is about 300 to 500 mm, and after the sintered raw material is ignited on the surface layer in the ignition furnace 5, it is transferred to the wind box 10 provided at the bottom of the pallet 2.
Then, air is sucked and vented downward to perform firing.

The combustion zone 8 is controlled to move downward at a speed of usually 20 to 30 mm/min and reach the lowest layer at the ore discharge section 11.

Incidentally, the firing progress from the ignition furnace 5 to the ore discharge section 11 (in the present invention, the firing progress refers to the depth of the sintered layer at any position in the moving direction of the pallet 2, that is, the strand direction or the width direction.

) can be schematically represented as shown in FIG.

In the figure, 7 is an unsintered layer, 8 is a combustion zone, and 9 is a sintered layer that has been completely fired.

Further, if an arbitrary point is taken in the moving direction of the pallet 2 and the intersections of the upper edge 13a and the lower edge 13b of the diagonally shaded portion 13 indicating the combustion zone 8 in the vertical direction A-A' with the vertical plane 14 are B and B', respectively. The distance between B and B' indicates the thickness of the combustion zone 8.

Now, the temperature distribution along the vertical plane 14 of the unburned layer 7, combustion zone 8, and sintered layer 9 is roughly as shown in FIG.

In Figure 3, the horizontal axis represents temperature ('C), and the vertical axis represents the distribution of the unburned layer 7, combustion zone 8, and sintered layer 9, that is, the distribution in the thickness direction of the sintered raw material. be.

By detecting the temperature in the vertical direction from near the surface layer of the sintered raw material layer, it is possible to know the firing progress or firing speed (in the present invention, the firing speed refers to the speed at which the combustion zone 8 moves downward from the surface layer). becomes possible.

Hereinafter, a method for detecting the temperature of the sintered raw material layer will be described in detail.

FIG. 4 is a partial sectional view of the sintered raw material layer on the pallet for explaining the temperature detection method of the present invention.

In the figure, 15 is a heat-resistant cylinder whose upper end is open, and 16 is a temperature detection end.

The cylindrical body 15 is inserted between the sintering raw material supply device 4 and the ignition furnace 5, or into the sintering raw material layer immediately after passing through the ignition furnace 5.

The temperature detection end 16 is inserted into the cylindrical body 15 so as to be vertically movable.

The temperature sensing end 16 in this embodiment is suspended by a winding drive device, for example, a sensing end lifting device 19 having an electric motor 17 and a winding drum 18, as shown in a side sectional view in FIG. It is configured to move up and down by doing this.

In FIG. 4, 20 indicates a temperature display device, and 21 indicates a lift amount display device.

In order to detect the temperature of the sintering raw material layer in the present invention, first, a cylinder is placed between the sintering raw material supply device 4 and the ignition furnace 5, or at any position of the sintering raw material layer immediately after passing through the ignition furnace 5. Insert the body 15.

Next, when the cylinder 15 passes through the ignition furnace 5, the detection end lifting device 19 is placed on the surface of the sintering raw material layer, and the temperature detection end 1 is placed on the surface of the sintered raw material layer.
6 is set so that it hangs down into the cylindrical body 15.

Thereafter, the electric motor 17 is driven continuously or intermittently to lower the temperature detection end 16 and measure the temperature at any part within the cylinder body 15.

That is, by measuring the atmospheric temperature or inner wall temperature inside the cylinder 15, the temperature at a predetermined level in the vertical direction of the sintering raw material layer (the predetermined level means a level at a predetermined depth from the surface layer of the sintering raw material layer) can be indirectly determined. It is measured based on the

That is, by measuring the temperature at that level while detecting the amount of elevation of the temperature detection end 16 from the reference level using the elevation amount display device 21, the temperature of the sintering raw material layer at the predetermined level can be detected. By sequentially changing the levels, it is also possible to detect the temperature distribution in the vertical direction as shown in FIG.

In addition, a plurality of cylinders 15 are inserted in the width direction or strand direction of the pallet 2, and a temperature detection end 16 is inserted into each of them.
Of course, it is also possible to detect the relative temperature distribution in the width direction or strand direction by inserting the strand.

As described above, the present invention involves inserting the cylindrical body 15 into the sintering raw material layer, and indirectly measuring the temperature or temperature distribution in the vertical direction of the sintering raw material layer through the cylindrical body 15. Therefore, as for the cylindrical body 15. The temperature change in the vertical direction of the sintering raw material layer can be accurately transmitted to the inside thereof, and the ignition furnace 5
It must have heat resistance that will not cause burnout or thermal deformation during movement from the ore discharge section 11 to the upper and lower movements of the temperature detection end 16.

According to the experience of the present inventors, ceramic materials such as alumina or zirconia can transmit the temperature change extremely accurately and are very effective.

However, even when a steel pipe such as ordinary steel or stainless steel is used as the cylinder 15, the thermal conductivity is better than that of the ceramic pipe, so the boundary of temperature change becomes somewhat unclear (as proposed by the present inventors). According to the experimental results, with respect to the set temperature of the sintering raw material layer, the variation was within 10 mm for the alumina cylinder 15, but was about 20 mm for the stainless steel pipe with a wall thickness of 1 mm.

) was confirmed to be sufficiently possible to grasp relative trends.

Therefore, the material of the cylindrical body 15 may be appropriately selected depending on the management purpose, measurement frequency, etc., as long as it has the above-mentioned functions.

In the present invention, the heat-resistant cylindrical body 15 is used in this sense.

Now, FIG. 6 is a chart showing the results of measuring the temperature of the sintering raw material layer in a 180 m'' class DL sintering machine using an alumina bottomed tube as the cylinder 15.

In other words, Figure 6A shows the vertical temperature distribution at position a, which is 25 m away from the ignition furnace 5, and position b, which is 30 m away from the ignition furnace 5. This is the distribution of directions.

In Figure 6B, the temperature detection end 16 is placed 20 degrees from the surface of the sintered raw material.
This figure shows the temperature distribution in the strand direction that was fixed at a depth of 0 mm and was continuously measured from the ignition furnace 5 to the ore discharge section 11 at that level.The horizontal axis shows the distribution in the strand direction, and the vertical axis shows the temperature (℃ ).

As is clear from FIG. 6, although the measurements were made indirectly through the cylinder 15, it was confirmed that the temperature or temperature distribution of the sintering raw material layer could be reliably determined.

Now, FIG. 7 is a block diagram showing another embodiment based on the present invention.

The temperature detection end 16 in this embodiment is suspended by a detection end lifting device 19 as in the embodiment shown in FIG. The temperature setting device 23 is inputted.

In the temperature setting device 23, a predetermined temperature, for example, an average temperature of 700° C. on the upper surface of the combustion zone 8 as shown in FIG. The temperature setter 23 compares the detection values continuously inputted from the detection end 16, and the electric motor 17 is driven and controlled based on the comparison result.

If the temperature setting device 23 is set to, for example, 700° C., the temperature detection end 16 will stop at a position substantially corresponding to the upper surface of the combustion zone 8, and the combustion zone 8 will descend as the pallet 2 advances.
Following this, the temperature detection end 16 also falls sequentially.

Therefore, by recording and/or tracking the descending state and descending speed of the temperature detection end 16 using the display device 24, it is possible to confirm the distribution of the set temperature in the strand direction of the sintering raw material layer, that is, the descending speed of the combustion zone 8. It is also possible.

Fig. 8 is a chart showing the results of a follow-up investigation of the temperature setting device 23 set at 700°C based on the example shown in Fig. m), where the vertical axis is the depth from the surface layer of the sintered raw material.

As is clear from FIG. 8, the combustion zone 8 is
It became possible to accurately grasp the descent status of the aircraft.

In the present invention, "continuously measuring" refers to continuously measuring the temperature of the sintered raw material layer as in the embodiments shown in FIG. 6B and FIG. This means that each time the cylindrical body 15 advances a predetermined distance from the ignition furnace 5, or after passing through the ignition furnace 5, as in the embodiment shown in FIG. 6A,
This means that the measurement is performed every predetermined period of time or whenever necessary.

As detailed above, the present invention continuously or intermittently measures the temperature inside the cylinder 15 inserted into the sintering raw material layer, and grasps the vertical temperature or temperature distribution of the sintering raw material layer. This made it possible to know the firing status of the sintering raw material, that is, the firing rate.

If the firing speed can be confirmed, the operator can quickly grasp whether the firing is going smoothly or not. If the difference is large compared to the firing speed, immediately adjust various control factors such as the moving speed of pallet 2, the charging amount of sintering raw materials, charging distribution, the composition of sintering raw materials, and the wind box. damper opening, ignition strength,
Operation can be optimized by appropriately controlling the moisture content of the sintering raw material.

As mentioned above, the present invention not only provides important information online to determine whether or not firing is appropriate, but also provides information on how changing control factors affects firing. This provides an important means of searching for information.

[Brief explanation of the drawing]

Figure 1 is a schematic illustration of the DL sintering equipment, Figure 2 is a schematic diagram explaining the progress of sintering, Figure 3 is an illustration of the temperature distribution in the vertical direction of the sintering raw material, and Figures 4 and 7 are used in this book. Schematic configuration diagrams showing different embodiments for carrying out the temperature detection method of the invention, FIG. 5 is a side sectional view of the detection end lifting device, and FIGS. 6 and 8 show the results of one implementation based on the present invention. Figure 6A is a vertical temperature distribution diagram of the sintered raw material, Figure 6B is a temperature distribution diagram of the sintered raw material in the strand direction at a predetermined level, and Figure 8 is a temperature distribution diagram of the sintered raw material in the strand direction. It is a graph which shows the correlation of the fall situation with respect to the strand direction of the predetermined temperature in a sintering raw material layer. 1... Sprocket wheel, 2...
Pallet, 3...Bedding layer supply device, 4...
...Sintering raw material supply device, 5...Ignition furnace, 6...
...Bedding layer, 7...Unsintered layer, 8...
... Combustion zone, 9... Sintered layer, 10...
Wind box, 15... Cylindrical body, 16...
...Temperature detection end, 17...Electric motor, 18...
... Winding drum, 19 ... Sensing end lifting device, 20 ... Temperature display device, 21 ... Lifting amount display device, 22 ... Temperature converter, 23...
... Temperature setting device, 24 ... Recording display device.

Claims (1)

[Claims] 1. A heat-resistant cylinder with an open top end is inserted into the raw material layer on the pallet of a moving grate type sintering machine, and then a temperature detection end is inserted into the cylinder so as to be movable up and down, and the temperature of any part inside the cylinder is measured. A method for detecting the temperature of a sintered raw material layer, the method comprising indirectly measuring the temperature or temperature distribution in the vertical direction of the raw material layer by continuously or intermittently measuring the temperature.