JPH03183712A - Fluidized bed apparatus - Google Patents

Abstract

PURPOSE:To drastically improve the yield of pre-reduced powdery ore by fitting a ceramic porous filter to inside of outlet for exhaust gas in a pre-reduction furnace at the time of pre-reducing the powdery ore with a fluidized bed type pre-reduction furnace. CONSTITUTION:At the time of smelting the molten metal by supplying the oxide powdery ore to a smelting reduction furnace after pre-reducing with the fluidized bed pre-reduction furnace 1, the powdery ore from a raw material supplying hole 6 is supplied into the pre-reduction furnace 1 and also high temp. reducing gas 2 exhausted from the smelting reduction furnace is blown from a gas inlet 3, blown up through a gas dispersion plate 4 and the fluidized bed 5 for powdery ore is formed to execute the pre-reduction and this is supplied into the smelting reduction furnace from a discharging hole 7 as the pre-reduced ore. In this case, filters 11, 12 composed of porous ceramics are fitted at inside of the furnace in an exhaust holes 8, 9 for exhaust gas in the fluidized bed pre-reduction furnace 1, and after collecting the powdery ore discharged accompanying to the exhaust gas, the powdery ore stuck to the filters 11, 12 is returned back into the fluidized bed 5 by backwashing with N2 gas, etc., and the powdery ore is pre-reduced with extremely high yield.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to the structure of a fluidized bed apparatus used for fluidizing and pre-reducing powdered ore.

[Prior Art J] There is a circulating fluidized bed device that circulates particles as a fluidized bed device that fluidizes powder and granules to cause heating or reaction. (a) An internal circulating fluidized bed device 21 in which a cyclone is installed inside the fluidized bed device, and (b) an external circulating fluidized bed device 22 in which a cyclone is installed outside the fluidized bed device. Multiphase flow Jv
ol, 2. No. 4 December 1988).

Internal circulation fluidized bed device 21 of such a free circulation type fluidized bed
is equipped with internal devices such as cyclones in the fluidized bed tower.
There are problems in the maintenance and management of such internal devices.

In addition, conventional circulating fluidized bed ore collectors generally use a cyclone. In order to increase the collection efficiency of the cyclone, multi-cyclones are particularly used, but ores with small particle diameters or ores that easily become powdered during circulation are not sufficiently collected by the cyclone collection device. There is a problem that it is discharged outside the system and the yield is extremely low.

[Problems to be Solved by the Invention] An object of the present invention is to provide an internally circulating fluidized bed apparatus that eliminates the above-mentioned drawbacks.

[Means for Solving the Problems] The present invention is a fluidized bed apparatus for fluidizing powdered ore, and is characterized in that a porous filter for filtering exhaust gas is provided on the inner wall of the furnace at the gas outlet of the fluidized furnace. This is a fluidized bed device.

This filter separates the exhaust gas and the fine ore, forming a free internal circulation flow device in which the exhaust gas does not carry the fine ore out of the flow furnace. It is preferable to use a ceramic filter as the porous filter because it can provide a filter with fine pores that has excellent durability and heat resistance, and it maintains an appropriate passage resistance by backwashing.

[Operation 1] In the sulfurizing furnace according to the present invention, a portion of the upper wall thereof constitutes a wall surface by a porous filter. This filter wall surface is divided into multiple blocks, and each block is sequentially backwashed to remove deposits from the filter surface.
Ore can be collected without clogging the filter, and continuous operation of the fluidized bed is possible.

[Example 1] Fig. 1 shows a longitudinal sectional view of an embodiment of the present invention, and Fig. 2 shows its +1-II blind view.

The fluidized bed apparatus 1 has a gas port 3 for introducing fluidizing gas 2 into the furnace bottom, and the gas passes through a dispersion plate 4 and enters a fluidized bed 5 to fluidize the powdered ore. Powdered ore raw material is supplied to the fluidized bed 5 from a raw material supply port 6 . The fluidized and treated ore is discharged from the fluidized bed 5 through a discharge lower.

The fluidizing gas is discharged through the gas outlet 8.9. This outlet 8.9 is provided with an alumina ceramic porous filter 11.12.

The porous filter 11.12 separates the powdered ore blown up together with the gas from the fluidized bed 5 and allows only clean gas to pass through. The outlet 8.9 has at least two lines, each independently equipped with a porous filter and a backwashing device (not shown).

The backwashing device filters pressure gas such as N2 gas through filter 11.1.
2 is sprayed in the opposite direction to the normal gas passage direction to peel off the powdered ore attached to the filter surface. The exfoliated powdery ore falls into the fluidized bed 5 and circulates within the fluidized bed apparatus.

Backwashing is performed for each discharge port divided into multiple lines, and is carried out by spraying cleaning gas for a short period of time. therefore,
The filter can be cleaned while the fluidized bed apparatus l continues to operate.

FIG. 2 shows a view taken along arrow II-II in FIG. 1, and shows the ceramic filter 11 having a cylindrical shape. This shape is not limited to this, but may be one in which arcuate or polygonal segments are arranged continuously or intermittently. Further, design changes can be made freely depending on the scale of the furnace, such as providing a collecting pipe around the fluidized bed device.

The apparatus shown in Figure 1 was operated under the following operating conditions.

Reducing gas amount: 3000 Ngo/H Fluidized bed temperature: 750℃ Ore supply arc to fluidized furnace: 650kg/H fluidized bed: Tower diameter: 1.7mφ.

Tower height: 8.5 m/+1 Porous filter: Inner diameter: 1.7 mφ, filter section height = 5 m As a result, smooth operation can be continued, and the amount of powdered ore entrained in exhaust gas is reduced to 1. g/Nrn'.

[Effects of the Invention] In the conventional external cyclone method, the ore collection efficiency is at most 91.4%, and in the present method, it is 99.99%.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an apparatus according to an embodiment of the present invention, FIG. 2 is a view taken along the arrows n to ■, and FIG. 3 is a schematic diagram showing the type of a conventional circulating fluidized bed. l...Fluidized bed device 2...Fluidization gas 3...
Gas population 4...dispersion plate 5...fluidized bed
6... Supply lower... Discharge port 8.9.
...Gas outlet 11% 12...Porous filter

Claims (1)

[Scope of Claims] 1. A fluidized bed apparatus for fluidizing powdered ore, characterized in that a porous filter for filtering exhaust gas is provided on the inner wall of the furnace at the gas outlet of the fluidized furnace. 2. The fluidized bed apparatus according to claim 1, wherein the porous filter is a ceramic filter.