JPH09125165A - Operation of sintering and sintering pallet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the sintering yield at side wall part by shortening the width of a suction part at the lower end of a pallet carriage than the width of a fire grate fitting part to restrain the air flow at the position near the side walls of the pallet carriage, at the time of sintering the packing layer of sintering raw material. SOLUTION: The sintering raw material is charged in the side walls 2 on the fire grate surface 1 of the pallet carriage having wheels 3, and the packing layer of the sintering raw material is burnt while sucking the air from the lower part of the fire grate surface 1. In the sintering pallet, the side walls 10 at the lower part of the fire grate surface are arranged by inclining to the inside from just below the side walls of the raw material packing part of the sintering pallet, and the width of the sucking part 4 at the lower end of the pallet carriage is made to shorter than the width of the fire grate fitting part. The suction quantity of the air to the side wall part is reduced with this blasting control part, and it is prevented to flow the excess air into the part near the side walls, and the aggravation of the sintering yield is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sintering operation method and a pallet trolley structure, and in particular, it is possible to significantly improve the yield and quality by controlling the air flow distribution in the packed bed in the pallet trolley. Operation method and pallet truck structure.

[0002]

2. Description of the Related Art In a Dwightroid type sintering process, for example, as shown in FIG. 1, a sintering raw material (c) containing powder coke filled on a grate 1 of a pallet truck (a) is ignited in an ignition furnace. Then, the air is sucked downward with a suction blower to perform firing. In the figure, 3 is a wheel of the pallet truck, 4 is a suction width of the wind box (b) at the lower end of the pallet truck, and 5 is an air seal portion with the wind box. At this time, the side wall 2 of the pallet truck
In the vicinity of the part, the wind speed rises from the central part of the packed bed due to the wall effect,
Excessive air flow. Further, as the firing progresses, the sintering raw material is hardened, so that a gap is generated in the side wall portion, which promotes the effect of excessive air flow. For these reasons,
It is known that in the vicinity of the pallet truck side wall 2 part, the firing time is shortened by the excess air as compared with the central part, and the yield is deteriorated. In order to solve this problem, for example, Japanese Patent Laid-Open No.
In Japanese Patent Laid-Open No. 5-104440, a method is proposed in which the width of the grate at the end of the pallet truck side is enlarged and blinded to reduce the amount of passing air flow and suppress the unevenness of the wind speed in the width direction of the pallet truck. In Japanese Utility Model Laid-Open No. 63-5389, a protrusion is arranged on the inner surface of the side wall of the sintering raw material filling portion of the pallet truck.
A method of adjusting the air volume near the side wall has been proposed.

Also in the pallet truck structure, the main frame of the truck is rectangular as seen in Japanese Utility Model Laid-Open No. 54-139003, and the side wall of the truck and the sintering raw material are supported by a cantilever extending from the upper surface of the frame. ing.

[0004]

However, when the width of the grate at the end of the pallet truck side is enlarged and blinded, the yield decrease due to the shortening of the firing time in the vicinity of the side wall can be prevented, but the width of the side end is reduced. In some of the raw material just above the expanded grate, an airless part was generated, so an unburned part remained, and the total yield improvement effect was not remarkable. Further, when the protrusions are arranged on the inner surface of the side wall of the sintering raw material filling portion of the pallet truck, the contact area between the sintering raw material and the side wall increases, so that the heat dissipated from this portion is large and the vicinity of the side wall is large. Since the firing temperature of the raw material is lowered, and the protrusion of the side wall portion disturbs the segregation of the raw material in the packed layer at the time of charging the raw material, there is a problem that the firing is adversely affected. I couldn't see it. Further, even in the pallet truck structure, there are many problems to be solved such as bending of the beam due to an extreme temperature gradient in the thickness direction of the cantilever projecting and stress concentration on the beam root.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems in the prior art, the present invention prevents excessive flow of air near the side wall during firing in a sintering raw material filling layer in a pallet truck. The summary is as follows. (1) In the sintering raw material packed bed in the pallet truck, the width of the suction portion at the lower end of the pallet truck was made shorter than the width of the grate attachment portion in order to prevent excessive air flow to the vicinity of the side wall during firing. A sintering operation method characterized by operating using a pallet truck. (2) In a sintering pallet in which a raw material is inserted on a grate and air is sucked from below to sinter, the amount of air sucked to the side walls is reduced on both side walls of the lower surface of the sintering pallet. A sintering pallet characterized by having a narrowed portion. (3) In the sintering pallet in which the raw material is inserted into the grate and air is sucked from below to sinter, the both side walls of the lower surface of the sintering pallet grate are inward from immediately below the side wall of the raw material filling part of the sintering pallet. A sinter pallet characterized by being installed at an angle.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the first place, the wind velocity increases in the raw material packed bed near the side wall of the pallet truck because the porosity between the raw material particles and the wall surface becomes larger than that in the case where the raw material particles are filled with each other. Is. Therefore, in order to reduce the wind speed in the vicinity of the side wall, the porosity of the raw material filling layer itself in the vicinity of the side wall is decreased. There are two possible methods of giving some resistance to the suction air passing near the side wall of the pallet truck at a portion other than the raw material packed bed.

The method of the present invention belongs to this latter method, but in the conventional technique, the portion for giving a resistance to the suction air passing near the side wall of the pallet truck is located at or above the grate surface. However, this method is a method of giving resistance to the suction air passing through the side wall vicinity in the portion of the pallet truck located below the grate surface,
As shown in FIG. 2, the width 4 of the suction portion at the lower end of the pallet truck is made smaller than the width 1 of the grate attachment portion. In the pallet trolley having such a structure, the portion near the side wall of the raw material charging portion is not located immediately above the suction portion, and the wind speed passing through the raw material filling portion near the side wall is lower than that in the pallet trolley having the normal structure. Moreover, since a normal great bar (grate) is used at the end of the pallet truck side, there is no problem of leaving unburned parts such as when the great bar (grate) at the side end is blinded. In addition, with such a pallet truck,
The structure above the grate surface is exactly the same as the conventional one,
There is no risk of adverse effects on firing.

The wind speed in the pallet width direction was investigated in the sintering simulation furnace shown in FIG. In this device, the wind box suction area adjusting plates 7 are attached to both ends of the suction wind box section to set the width E of the suction section.
Has a variable structure. The raw material was charged into this device, and the average wind velocity (A) in the vicinity of the side wall and the average wind velocity (B) in the center of the furnace during the firing period after ignition were measured by the anemometer attached to the upper surface of the raw material packed bed. It was calculated. FIG. 4 shows the ratio of the width (D) of the grate surface to the width (E) of the air box suction portion, the so-called throttle ratio (F = D / E) and the wind speed ratio (C = A / B) to the central portion near the side wall. Shows the relationship with. The wind speed ratio (C) with respect to the central portion near the side wall shows almost no change in the range where the aperture ratio (F) is 1.05 or less, but when the aperture ratio (F) becomes 1.05 or more, the wind velocity ratio (F) increases as the aperture ratio (F) increases. The wind speed ratio (C) is reduced, and the excess air amount near the side wall is suppressed.

FIG. 5 shows the relationship between the drawing ratio (F) and the average wind speed (B) in the central part of the furnace. The average wind speed (B) in the central part of the furnace is
When the aperture ratio (F) is 2.5 or less, there is no large change, but when the aperture ratio (F) is more than that, there is a phenomenon of decrease. This is because the insertion plate increases the pressure loss of the gas passing therethrough, so that the air passing through the raw material packed bed is reduced as a whole by the pressure loss. If the amount of air passing through the raw material packed bed in the central part of the furnace decreases, the productivity will decrease in the actual sintering operation, so the reduction ratio (F) is 1.05.
It is desirable to operate within the range of from 2.5 to 2.5.

The above is the embodiment of the pallet truck of the type shown in FIG. 2. In this case, the trolley structure is such that the frame structure of the pallet truck of the current type is retained while the heat-resistant throttle member is provided on the grate surface. Install on the bottom surface.

As shown in FIG. 6, a pallet truck having a squeezing structure for making the width of the lower end of the pallet (width of the wind box suction portion) 4 as usual and widening the width of the grate attachment portion is used. If so, the amount of the raw material filled can be increased by the amount corresponding to the increase in the width of the grate attachment portion, so that the production capacity can be improved.

In this case, the shape shown in FIG. 7 which is a further improved pallet truck structure is practical. That is, both side wall portions 10 below the grate surface of the sintering pallet are inclined, the side wall portion of the main body frame is formed into an inverted C shape, and the side wall portion of the main body frame itself is located between the lower end of the side wall of the sintering raw material filling portion and the lower end of the pallet carriage. By forming a narrowing portion toward the suction portion, the sintering raw material filling portion including the side wall is supported by the entire main body frame. If the width of the grate mounting portion is increased or the side wall of the throttle is curved to improve the strength, it is possible to increase the side wall height to about 60% or more, that is, 250 to 300 mm on one side.

By adopting such a structure, the cantilever structure of the side wall of the sintering raw material filling portion is avoided, and the temperature gradient in the wall thickness of both side walls under the sintering pallet grate surface is almost the same as the conventional type. Can be Rather, heat dissipation from the frame side wall loosens the wheel part, and the temperature of the lower part of the main frame rises slightly, reducing the temperature difference between the upper and lower parts of the main frame and suppressing the bending of the truck due to the difference in thermal expansion coefficient. It is possible to maintain the same level of strength as the current pallet truck up to the width expansion width. Further, in order to reduce the stress on the frame side wall portion and the lower portion of the main body frame, it is effective to use the conventional three-division structure having the division portion 11 of the truck as shown in FIG.

[0014]

[Example] Based on the result of the sintering simulation furnace, a test pallet prototyped with a drawing ratio (F) of 1.4 (structurally similar to that of FIG. 2) was used for ironmaking with a grate width of 3.5 m. A firing test was performed with a sintering machine. The test was carried out while keeping the operating conditions shown in Table 1 constant.

[0015]

[Table 1]

FIG. 9 shows the wind speed distributions of the test pallet and the normal pallet during firing, and Table 2 shows the yield. The yield here is the weight of the sintered ore of +5 mm grain size after crushing the sinter ore 9 taken from the range shown in FIG. 10 of the sinter cake extracted with the pallet truck after firing with a tumbler strength tester. Is a ratio.

[0017]

[Table 2]

In the test pallet, the wind speed in the vicinity of the side wall is much lower than that in the normal pallet, and the yield in the vicinity of the side wall is about 25%.
It was confirmed that the yield of the entire pallet was improved by 3.6%. Even when the pallet truck of the type shown in FIGS. 6 to 8 is used, the wind speed in the vicinity of the side wall is greatly reduced, the yield in the vicinity of the side wall is improved, and the production capacity is also improved. It is possible and more preferable.

[0019]

The sintering operation method using a pallet truck according to the present invention makes it possible to greatly improve the yield near the side wall of the pallet truck, which has been low in the past, and to reduce the manufacturing cost. The effect is extremely large.

[Brief description of the drawings]

FIG. 1 is a front view of a conventional pallet truck.

FIG. 2 is a front view of a pallet truck having a throttle structure below the grate surface used in the present invention.

FIG. 3 is a front view of a sintering simulation furnace.

FIG. 4 is a view showing a relationship between a throttle ratio F (grate surface width / wind box suction part width) and a wind speed ratio C (average wind speed near a side wall / average wind speed at a furnace center).

FIG. 5 is a diagram showing a relationship between a reduction ratio F (width of a grate surface / width of a wind box suction part) and an average wind speed in a central part of a furnace.

FIG. 6 is a front view of a pallet truck according to the present invention having a throttle structure below the grate surface and having a wide grate surface.

FIG. 7 is a front view of a pallet truck having a throttle structure composed of a main body frame side wall portion below the grate surface of the present invention and having a wider grate surface.

FIG. 8 is a front view of a pallet truck according to the present invention, which has a throttle structure composed of a main body frame side wall portion below the grate surface, has a widened grate surface, and is further divided into three main body frames.

FIG. 9 is a view showing wind speed distributions in the width direction of a normal pallet truck and a test pallet truck.

FIG. 10 is a view showing a material sampling position at the time of measuring yield in the example of the present invention.

[Explanation of symbols]

 1 Grate surface (Great bar) 2 Pallet trolley side wall 3 Wheels 4 Wind box suction width at the bottom of pallet trolley 5 Air seal part with wind box 6 Squeezing structure 7 Wind box suction area adjusting plate 8 Sinter cake 9 Sampling part 10 Grate Side wall under the surface 11 Dividing part of pallet truck

Front page continued (72) Inventor Iwao Yasunaga 5-3 Tokai-cho, Tokai City Nippon Steel Co., Ltd. Nagoya Steel Works (72) Inventor Akifumi Umezu 5-3 Tokai-cho Tokai-shi Nippon Steel Co., Ltd. Nagoya Inside the ironworks

Claims (3)

[Claims] 1. The width of the suction portion at the lower end of the pallet truck is set to be larger than the width of the grate attachment portion in order to prevent excessive air flow in the vicinity of the side wall during firing in the sintering raw material packed bed in the pallet truck. A sintering operation method characterized by operating using a shortened pallet trolley. 2. In a sintering pallet in which a raw material is inserted on a grate and air is sucked from below to sinter, a suction amount of air to a side wall part is set to both side walls at a lower part of the sintering pallet grate surface. A sinter pallet, which is provided with a squeezing section for reducing the number. 3. In a sintering pallet in which a raw material is inserted on a grate and air is sucked from below to sinter, both side walls of the lower surface of the sintering pallet grate are directly below the side wall of the sintering pallet raw material charging part. A sinter pallet characterized by being inclined inward from the inside.