JP6569660B2 - Grizzly equipment - Google Patents

Description

  The present invention relates to a grizzly device for removing fine powder from a blast furnace raw material.

  A grizzly device is known in which a plurality of grizzly bars are arranged in parallel at a predetermined interval to classify a raw material having a particle size smaller than the grizzly bar interval and a raw material having a particle size larger than the grizzly bar interval. . This grizzly device can be provided on a raw material conveyance line, and is superior to a device using a sieve such as a screen in that it has a simple configuration and a high classification processing capability.

  As an example of a grizzly device, Patent Document 1 discloses that the height of the top surface of a grizzly bar is gradually lowered from the center to the left and right, and the level difference between adjacent grizzly bars increases from the raw material supply side to the discharge side. A grizzly device is disclosed. It is disclosed that by increasing the level difference of the grizzly bar as it goes from the raw material supply side to the raw material discharge side, a lateral rotational force is imparted to the raw material rolling on the grizzly bar, thereby suppressing clogging of the grizzly bar. ing.

  Patent Document 2 discloses a grizzly device provided with an elevating guide for guiding the grizzly bar in the vertical direction. By providing an elevating guide that guides the grizzly bar up and down, even if clogging occurs, the grizzly bar can be moved up and down using the elevating guide to widen the interval between the grizzly bars. Thus, it is disclosed that clogging can be easily eliminated.

Japanese Utility Model Publication No. 61-98582 Japanese Utility Model Publication No. 61-98581

  For example, coke, which is one of the blast furnace raw materials, is sieved into lump coke with a particle size of more than 30 mm and small medium lump coke / powder coke with a particle size of 30 mm or less before being transferred to the blast furnace, It is used after being classified into small and medium lump coke having a diameter of more than 8 mm and not more than 30 mm and powder coke having a particle diameter of not more than 8 mm. When classifying small and medium lump coke and powdered coke using a grizzly device, the interval between the grizzly bars is adjusted to 8 mm. The powder coke has a particle size smaller than the interval, so that it can pass through the interval of the grizzly bar (hereinafter, the interval of the grizzly bar is referred to as “opening”), while the small coke coke has a particle size larger than that of the opening. It is so large that it cannot pass through the opening. Thereby, small and medium lump coke and powder coke are classified.

  However, when the coke flows on the grizzly bar without contacting the opening, the coke is not classified because the powder coke does not pass through the opening, and the classification efficiency of the grizzly device is reduced. The present invention has been made in view of such problems, and its purpose is to change the flow direction of the blast furnace raw material flowing on the grizzly bar when classifying the blast furnace raw material using the grizzly device, and to open the opening. An object of the present invention is to provide a grizzly device with improved classification efficiency by reducing the amount of blast furnace raw material that does not come into contact with the blast furnace.

The features of the present invention that solve such problems are as follows.
(1) A grizzly device having a plurality of grizzly bars provided along a conveying direction of a blast furnace raw material, wherein the plurality of grizzly bars are inclined so as to be lowered toward the conveying direction at a predetermined interval. A grizzly device provided with a convex portion on at least one upper surface of the plurality of grizzly bars.
(2) The grizzly device according to (1), wherein the convex portion is provided in a region in a range of 0 to 75% from the upstream side in the transport direction on the upper surface of the grizzly bar.
(3) The grizzly device according to (1), wherein the convex portion is provided only in a region within a range of 25 to 75% from the upstream side in the transport direction on the upper surface of the grizzly bar.
(4) The grizzly device according to any one of (1) and (3), wherein a height of the convex portion is 0.5 times or more a maximum value of the predetermined interval.
(5) The difference between the width of the upper surface of the grizzly bar provided with the convex portion and the width of the convex portion is not more than 0.5 times the maximum value of the predetermined interval. The grizzly device according to any one of (4).

  The grizzly apparatus according to the present invention can change the flow direction of the blast furnace raw material flowing on the grizzly bar to the opening side. Thereby, the blast furnace raw material which flows on a grizzly bar, without contacting an opening part can be decreased, and the classification efficiency of a grizzly apparatus can be improved.

It is a conceptual diagram which shows an example of the grizzly apparatus provided in the conveyance process which conveys coke to a blast furnace. It is a perspective view which shows an example of a grizzly device. It is the perspective view and side view which show an example of a grizzly bar. It is a graph which shows the mixing rate of the powder coke with a particle size of 5 mm or less contained in the small medium lump coke of a comparative example and an Example.

  FIG. 1 is a conceptual diagram illustrating an example of a grizzly device provided in a transporting process for transporting coke to a blast furnace. Using the example of classifying the coke 12 having a particle size of 30 mm or less into a small medium coke having a particle size of more than 8 mm and 30 mm or less and a powder coke having a particle size of 8 mm or less using the grizzly device according to the embodiment of the present invention, the following Examples will be described. In this embodiment, the particle size means a particle size that is sieved by a sieve. For example, the particle size of more than 8 mm is a particle size that is sieved on a sieve using a sieve having an opening of 8 mm. The particle size of 8 mm or less means a particle size that is sieved under a sieve using a sieve having an opening of 8 mm.

  Coke, which is one of the blast furnace raw materials, is first sieved into block coke having a particle size of more than 30 mm and coke 12 having a particle size of 30 mm or less. The coke 12 having a particle size of 30 mm or less is classified by the Grizzly device 10 into a small medium coke having a particle size of more than 8 mm and 30 mm or less and a powder coke having a particle size of 8 mm or less. Then, it is conveyed to the blast furnace 16 by the conveyor 14.

  FIG. 2 is a perspective view showing an example of a grizzly device. The grizzly device 10 includes an upper guide part 20, a sieve part 22, and a lower guide part 24. The upper guide unit 20 guides the coke 12 conveyed from the upstream side to the sieving unit 22. The sieving unit 22 classifies the coke 12 into a small medium mass coke having a particle size of more than 8 mm and 30 mm or less and a powder coke having a particle size of 8 mm or less. The lower guide portion 24 receives the small medium lump coke classified by the sieving portion 22 and guides the small medium lump coke to the conveyor 14. The grizzly device 10 may have a drive device that vibrates the grizzly bar 30.

  The sieving portion 22 is composed of, for example, seven grizzly bars 30. The seven grizzly bars 30 are provided so as to be parallel to each other along the conveyance direction of the coke 12 and to be inclined toward the conveyance direction. The interval between the seven grizzly bars 30 is 8 mm, and the inclination angle with respect to the horizontal plane is 40 °. Below the grizzly bar 30, a collection box (not shown) for collecting the powder coke that has passed through the opening 34 is provided. 8 mm is an example of a predetermined interval, and the interval is determined in advance by the particle size of the powder coke to be classified.

  FIG. 3 is a perspective view and a side view showing an example of a grizzly bar. FIG. 3A is a perspective view of the grizzly bar 30, and FIG. 3B is a side view of the grizzly bar 30 as viewed from the transport direction. As shown in FIG. 3A, the upper surface of the grizzly bar 30 is rectangular, the total length L1 is 500 mm, and the width L2 is 25 mm. Assuming that the grizzly bar 30 is divided into four regions every 125 mm from the upstream side in the transport direction, 0 to 25% on the upstream side is the region 40, 25 to 50% is the region 42, and 50 to 75 on the whole. % Is the region 44, and 75 to 100% is the region 46.

  A convex portion 32 is provided on the upper surface of the grizzly bar 30. The convex portion 32 is a cylinder having a diameter of 15 mm, and the corner portion of the upper surface is R-processed. Since the convex portion 32 is a cylinder having a diameter of 15 mm, the width L3 of the convex portion 32 is 15 mm. Moreover, the height L4 of the convex part 32 is 10 mm. In the present embodiment, two convex portions 32 are provided in each of the region 42 and the region 44 of the grizzly bar 30, for a total of four. The convex part 32 is the center in the width direction of the grizzly bar 30 and is provided at positions 25 mm and 100 mm from the upstream side in the transport direction in the region 42 and the region 44, respectively.

  The coke 12 guided by the upper guide portion 20 flows toward the lower guide portion 24 on the upper surface of the grizzly bar 30 inclined at 40 ° with respect to the horizontal plane. Since the grizzly bar 30 is provided in parallel at an interval of 8 mm, small and medium-sized coke having a particle size of more than 8 mm flows to the lower guide portion 24 without passing through the opening 34, while the powder having a particle size of 8 mm or less. The coke passes through the opening and falls below the grizzly bar 30 and is collected in a collection box. In this way, the coke 12 is classified into small and medium lump coke and powder coke.

  Further, when the coke 12 flows on the upper surface of the grizzly bar 30, it collides with a convex portion 32 provided on the upper surface of the grizzly bar 30, and the flow direction of the coke 12 changes. The collision direction of the coke 12 flowing on the upper surface of the grizzly bar 30 due to the collision with the convex portion 32 becomes a direction toward the opening 34, and the chance that the coke 12 contacts the opening 34 increases. Thereby, the coke 12 which flows to the lower guide part 24 without contacting the opening part 34 can be decreased. Coke having a particle size of 8 mm or less passes through the opening 34 with a predetermined probability determined by the particle size and shape by contacting the opening 34. For this reason, more powder coke can be passed through the opening part 34 by increasing the chance that the coke 12 contacts the opening part 34, thereby improving the classification efficiency of the grizzly device 10.

  On the other hand, in the conventional grizzly device in which the convex portion 32 is not provided, a part of the coke 12 flows on the upper surface of the grizzly bar 30 without contacting the opening 34, and the powder coke does not pass through the opening 34. Therefore, the mixing ratio of the powder coke contained in the small and medium lump coke increases, and the classification efficiency of the grizzly device decreases. The classification efficiency of small and medium lump coke charged to the blast furnace as blast furnace raw material decreases, and when small and medium lump coke containing a large amount of powdered coke is charged to the blast furnace, the air permeability in the blast furnace deteriorates. Stable operation is hindered.

  Since the grizzly device 10 according to the present embodiment is provided with the convex portion 32 on the upper surface of the grizzly bar 30, the flow direction of the coke 12 can be changed and the coke 12 can be positively brought into contact with the opening 34. Thereby, since the chance that the coke 12 contacts the opening part 34 increases, more powder coke can be passed through the opening part 34, the classification efficiency of the grizzly device 10 is improved. And the quantity of the powder coke contained in small and medium lump coke can be reduced by using the grizzly device 10 by which classification efficiency was improved in this way, and it can contribute to the stable operation of a blast furnace.

  Furthermore, since the grizzly device 10 according to the present embodiment can be manufactured by providing the convex portion 32 on the upper surface of the grizzly bar 30 in the conventional grizzly device, the present embodiment can be easily changed from the conventional device to the present embodiment. Such a grizzly device 10 can be manufactured.

  Moreover, in this embodiment, although the example where the grizzly bar 30 was provided in parallel with each other along the conveyance direction of the coke 12 was shown, it is not limited thereto. The grizzly bars 30 may not be parallel, and the sizes of the openings 34 may be different from each other. In such a case, the target particle size to be classified by the grizzly device is equal to or less than the maximum value of the opening 34.

  Moreover, in this embodiment, although the example which provided the convex part 32 in each of the area | region 42 and the area | region 44 was shown, it is not restricted to this, The convex part 32 is any of the area | regions 40, 42, 44, and 46. At least one or more may be provided in the region. Thereby, the flow direction of the coke 12 can be changed, and the chance that the coke 12 contacts the opening 34 can be increased.

  However, since the region 46 is close to the lower guide portion 24, even if the convex portion 32 is provided in the region 46 and the flow direction of the coke 12 is changed, the coke 12 flows to the lower guide portion 24 as it is. Even if the convex portions 32 are provided, the chance of contact with the openings 34 of the coke 12 does not increase as much as when the convex portions 32 are provided in the other regions 40, 42, 44. For this reason, it is preferable to provide the convex part 32 in the area | region 40,42,44. The regions 40, 42, and 44 correspond to a range of 0 to 75% from the upstream side in the transport direction on the upper surface of the grizzly bar 30.

  Furthermore, since the movement of the coke 12 immediately after being guided from the upper guide portion 20 is not stable, the coke 12 may escape upward even if a convex portion is provided in the region 40, and the convex portion is provided in the region 40. Even if 32 is provided, the opportunity to contact the opening 34 of the coke 12 does not increase as much as when the convex portions 32 are provided in the regions 42 and 44 where the movement of the coke 12 is stable. For this reason, it is more preferable to provide the convex portion 32 in the regions 42 and 44. The regions 42 and 44 correspond to a range of 25 to 75% from the upstream side in the transport direction on the upper surface of the grizzly bar 30.

  Moreover, although the example which made height L4 of the convex part 32 10 mm was shown in this embodiment, it is not restricted to this. Since the convex part 32 should just change the flow direction of the object to classify at least, for example, in the grizzly device 10 which classifies small and medium lump coke and powder coke, the height L4 of the convex part 32 is the powder coke. It may be 4 mm or more, which is half of the particle size. In the grizzly device 10, since the maximum value of the opening 34 corresponds to the particle size to be classified, the height of the convex portion 32 may be 0.5 times or more the maximum value of the opening 34. Thereby, it is possible to suppress the coke 12 flowing on the upper surface of the grizzly bar 30 from exceeding the convex portion 32, and to increase the chance that the coke 12 contacts the opening 34.

  In the present embodiment, the example in which the width L3 of the convex portion 32 is 15 mm is shown, but the present invention is not limited to this. When the width L3 of the convex portion 32 is narrower than the width L2 of the upper surface of the grizzly bar 30 provided with the convex portion 32, the difference between the width L3 of the convex portion 32 and the width L2 of the upper surface is that the coke 12 is convex. The width is such that it can flow on the upper surface without contacting the portion 32. As described above, if the coke 12 does not contact the convex portion 32, the flow direction of the coke 12 does not change, so the chance that the coke 12 contacts the opening 34 does not increase. For this reason, it is preferable that the difference between the width L3 of the convex portion 32 and the width L2 of the upper surface of the grizzly bar 30 is small. For example, in the grizzly device 10 for classifying small coke and powdered coke, the convex portion 32 has The difference between the width L2 of the upper surface of the grizzly bar 30 provided and the width L3 of the convex portion 32 may be 4 mm or less, which is half the particle size of the powder coke. In the grizzly device 10, since the maximum value of the opening 34 corresponds to the particle size to be classified, the difference between the width L2 of the upper surface of the grizzly bar 30 provided with the convex portion 32 and the width L3 of the convex portion 32 is The maximum value of the opening 34 may be 0.5 times or less. Thereby, the coke 12 flowing on the upper surface of the grizzly bar 30 collides with the convex portion 32, and the chance that the coke 12 contacts the opening 34 can be increased.

  Moreover, although the example which classify | categorizes the small medium lump coke which is a blast furnace raw material and powdered coke using the grizzly apparatus 10 which concerns on this embodiment was shown, it is not restricted to a coke but classifying with a grizzly apparatus 10 is a blast furnace raw material. Ore raw materials such as sintered ore, lump ore or pellets used as the above may be used.

  As an example, except that the number of the grizzly bars 30 is 35, the grizzly device having the same configuration as the grizzly device 10 shown in FIG. 2 and as a comparative example the same grizzly as the example except that the convex portion 32 is not provided. Apparatuses were prepared, and using these apparatuses, coke having a particle size of 30 mm or less was classified into small-medium coke having a particle size of more than 8 mm and 30 mm or less and powder coke having a particle size of 8 mm or less. Thereafter, the small coke was collected, and the mixing ratio of the powder coke having a particle size of 5 mm or less contained in the small medium coke was measured as an index indicating the classification efficiency.

  FIG. 4 is a graph showing the mixing ratio of powder coke having a particle size of 5 mm or less contained in the small and medium lump coke of the comparative example and the example. In FIG. 4, “Comparative Example” indicates the mixing ratio (mass%) of the powder coke having a particle size of 5 mm or less contained in the small and medium lump coke classified using the grizzly device not provided with the convex portion 32. “Example” indicates the mixing ratio (mass%) of powder coke having a particle diameter of 5 mm or less contained in small and medium lump coke classified using a grizzly device provided with convex portions. In addition, the mixing ratio of the powder coke having a particle diameter of 5 mm or less contained in the small medium lump coke was measured by collecting the small medium lump coke that flowed down the grizzly device and sieving it with a sieve having an opening of 5 mm.

  As shown in FIG. 4, by providing four convex portions 32 on each grizzly bar, the mixing ratio of powder coke of 5 mm or less is 4.5 mass% (comparative example) to 3.4 mass% (examples). ). From this result, by using the grizzly device 10 according to the present embodiment, the coke flow direction is changed to the opening side to increase the chance that the coke comes into contact with the opening, thereby improving the classification efficiency of the grizzly device. It was confirmed that it can be improved.

DESCRIPTION OF SYMBOLS 10 Grizzly device 12 Coke 14 Conveyor 16 Blast furnace 20 Upper guide part 22 Sieve part 24 Lower guide part 30 Grizzly bar 32 Convex part 34 Opening part 40 Area 42 Area 44 Area 46 Area

Claims (4)

A grizzly device having a plurality of grizzly bars provided along the conveying direction of the blast furnace raw material,
The plurality of grizzly bars are provided so as to be inclined toward the transport direction at a predetermined interval, and 0 to 75% from the upstream side in the transport direction on at least one upper surface of the plurality of grizzly bars . A grizzly device in which a convex portion is provided in a region that falls within the range, and no convex portion is provided in a region that is greater than 75% and equal to or less than 100% .   2. The grizzly device according to claim 1, wherein the convex portion is provided in a region that is within a range of 25 to 75% from the upstream side in the transport direction on the upper surface of the grizzly bar. The grizzly device according to claim 1 or 2 , wherein a height of the convex portion is 0.5 times or more a maximum value of the predetermined interval. The difference between the width of said convex portion of the upper surface of the grizzly bars the convex portions are provided, is less than 0.5 times the maximum value of the predetermined intervals, claims 1 to 3 The grizzly device according to any one of the above.

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