JPH03181790A - Fluidized-bed dispersion plate - Google Patents

Abstract

PURPOSE:To reduce an amount of fallen ore and improve a rate of recovery by a method wherein a sectional shape of a rod rostle arranged at a lower side is formed into a longitudinal rectangular shape. CONSTITUTION:A sectional shape of a rod-like rostle arranged at a lower side is formed into a longitudinal rectangular shape. It is preferable that a longitudinal length ratio at a section of the rod-like rostle is 2 to 5. As a result distance and required time for gas fed into a fluidized layer to pass through the rod-like rostle are elongated, the particles dropped in the midway are carried away upwardly by fed gas again so as to enable the particles to be prevented from being dropped. A long passing distance means that a pressure loss of gas at the rostle part is increased. Particles in the fluidized bed or layer can be smoothly fluidized by dispersing the gas fed into the fluidized bed properly in a radial direction of the fluidized bed furnace.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an improvement of a gas distribution plate used in a fluidized bed pre-reduction furnace, and more specifically, to a reduction in ore falling from the distribution plate and an increase in the reduction rate. This invention relates to a dispersion plate for achieving

[Conventional technology] Iron ore and other metal ore resources tend to be less in the form of lumps and more in the form of powder. Currently, ore beneficiation, such as flotation and magnetic separation, is being used to improve the quality of low-grade ores. It is expected that this trend will become even stronger in the future, partly because of the active progress being made in this area.

Therefore, in recent years, a so-called smelting reduction method has been developed to directly produce molten metal from powdered ore, in other words, the powdered ore is pre-reduced in a fluidized bed pre-reduction furnace, and the resulting pre-reduced ore powder is filled with a carbonaceous solid reducing agent. A method was developed in which metal is introduced into a melting reduction furnace where it is reduced and liquefied to form molten metal.

By the way, in a fluidized bed pre-reduction furnace, when the furnace diameter becomes large, the gas flow in the fluidized bed becomes uneven and proper fluidization becomes difficult, so in order to obtain a uniform gas flow, the reducing gas inlet is A gas distribution plate with a large number of gas distribution holes is provided in the lower part of the furnace.

When using high-temperature gas generated in a smelting reduction furnace as the fluidizing reducing gas, the generated gas contains a large amount of dust, which has the disadvantage of clogging the gas distribution plate.

In order to solve this problem, the applicant proposed, for example, Japanese Utility Model Application No. 62-29094.

As shown in FIG. 2, the gas dispersion plate disclosed in Japanese Utility Model Application Publication No. 62-29094 has a plurality of rotatable rod-shaped rotors 2 each having a circular cross section vertically intersecting each other inside the preliminary reduction furnace l. The rostol 2 is configured to be able to be inserted and removed via a short pipe 5 with a gas seal provided on the side wall of the preliminary reduction furnace 1, and is attached to the upper and lower surfaces of the rostol 2. This is to remove deposits 4 such as dust by inserting and removing the rotor 2 to prevent clogging of the dispersion plate 3.

[Problems to be Solved by the Invention] In the above-mentioned Japanese Utility Model Application Publication No. 62-29094, the cross-sectional shape of the rod-shaped rooster is circular.

Therefore, the distance that the reducing gas introduced into the fluidized bed passes through the distribution plate is equal to the diameter of the rostre.

In this case, even if the fine powder particles in the raw material fall through the roostle gap, there is a problem in that the reducing gas blows up the fine powder particles and they cannot be returned to their original state because the flow rate of the reducing gas is slow in the lower part of the roostle.

The present invention solves the above-mentioned problems of the prior art, increases the flow rate of the reducing gas blowing up the rostol gap, returns the falling fine particles to their original state, reduces the number of fallen ores, and increases the reduction rate through fluidized bed dispersion. The objective is to provide a board.

[Means for Solving the Problems J] The present invention solves the above-mentioned problems, and is applied to a fluidized bed dispersion plate in which a plurality of rod-shaped rostles are arranged vertically and intersectingly, and the following technical means are adopted. . Namely.

This is a fluidized bed dispersion plate characterized in that the cross-sectional shape of the rod-shaped rostle disposed on the lower side is a vertically elongated rectangle.

It is preferable that the aspect ratio of the cross section of the rod-shaped rostle be 2 to 5.

[Function] When the particles fluidized at the upper part of the rod-shaped roosts fall through between the rod-shaped roosts, the yield (production amount) decreases. Therefore, by making the cross-sectional shape of the rooster a vertically elongated rectangle, ■ the distance and time required for the gas introduced into the fluidized bed to pass through the rod-shaped roostor part become longer, and the particles that have fallen part way will be returned to the introduced gas. It can be carried upwards and restrained from falling.

■ The longer the passage distance, the greater the pressure loss of the gas in the roistle section. By appropriately dispersing the gas introduced into the fluidized bed in the radial direction of the fluidized bed furnace, it is possible to improve the overall fluidization of the particles in the fluidized bed.

[Example] An example of the present invention is shown in FIG. FIG. 1 shows an explanatory diagram of a cross section of the dispersion plate 3. As shown in FIG. 6 is the upper rostle,
7 is the lower rostle. In this example, the thickness of the lower lost lure is 30 mm, the height is 00 mm, and the lost distance is 25 mm.
mm, that is, the aspect ratio (height/thickness ratio) of the cross section of the rostol was configured to be 10/3.

This example was carried out under the following operating conditions.

Flow a N in IB 7 (') (1 mm Fluidizing gas temperature Fluidizing gas composition Fluidizing gas flow rate Rostle Material Processing Ore The operation results are 1st 995℃, 280ONrn'/h H2 17% N2 39% Co 43% Trace gas 1% 85 m/5 ec (flow rate in the ventilation section between the roosts) Heat-resistant metallic iron ore 15 t/h (average particle size 140 LLm) Shown in the table.

The falling ore rate is the amount of falling ore compared to the amount of processed ore.

According to Table 1, it can be seen that the present invention has a significant improvement effect on the falling ore rate and the reduction rate.

[Effect of the Invention 1 The present invention has excellent effects in reducing fallen ore and increasing the reduction rate.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a cross section of a dispersion plate of the present invention, and FIG. 2 is an explanatory diagram of a conventional example. 1... Pre-reducing furnace 2... Losttle 3... Dispersion plate 4... Deposit 5...- Short tube
6...-Upper Lost Rua...Lower Lost Rua

Claims (1)

[Scope of Claims] 1. A fluidized bed dispersion plate in which a plurality of rod-shaped rostles are arranged vertically and intersectingly, and the cross-sectional shape of the rod-shaped rostles disposed on the lower side is a vertically elongated rectangle. Board. 2. The fluidized bed dispersion plate according to claim 1, wherein the cross-sectional aspect ratio of the rod-shaped rooster is 2 to 5.