JPH11158522A - Equipment for recovering dust from exhaust gas in pre-reduction furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the blow-up of purge gas, etc., blown in a dust receiving equipment below a cyclone, into the cyclone and to improve the dust collecting efficiency of the cyclone. SOLUTION: In a dust recovering equipment in which the cyclone 4 is disposed for collecting the dust in an exhaust gas passage 3 for introducing the exhaust gas from a fluidized bed type per-reduction furnace 2 in a smelting reduction equipment, a receiving tank 7 for receiving the collected dust below this cyclone and a dust injecting means for supplying the dust in this receiving tank into the smelting reduction furnace are arranged, gas discharging passages A, B for discharging the gas in the receiving tank to the exhaust gas passage at the downstream side of the cyclone are formed. The blow-up of the gas of the purge gas, etc., supplied in the dust receiving equipment side, into the inner part of the cyclone from the lower end thereof, is prevented by making the pressure in the receiving tank lower than the pressure in the cyclone.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a smelting reduction facility having a smelting reduction furnace and a fluidized bed type pre-reduction furnace, which collects dust (fine ore) in exhaust gas discharged from the pre-reduction furnace. And a facility for supplying the same to a smelting reduction furnace.

[0002]

2. Description of the Related Art Conventionally, there is known an iron ore smelting reduction facility comprising a smelting reduction furnace and a fluidized bed type pre-reduction furnace. In this smelting reduction facility, CO and H ₂ generated in the smelting reduction furnace
Is introduced into a preliminary reduction furnace as a gas for fluidizing and reducing iron ore, and the preliminary reduction is performed while forming a fluidized bed of iron ore in the furnace.

[0003] Among iron ores (usually having a particle size of 8 mm or less) which have been subjected to a pre-reduction treatment in a pre-reduction furnace, those having a relatively coarse particle size are extracted by dropping under their own weight through an extraction pipe below a fluidized bed, and are supplied in a fixed amount. Is supplied to the smelting reduction furnace. On the other hand, fine iron ore (fine ore) is discharged from the upper part of the pre-reduction furnace along with the exhaust gas to the outside of the furnace.
Most of the ore is collected as dust by a cyclone on the exhaust gas path, and this fine ore (hereinafter, referred to as dust) is finally injected into a smelting reduction furnace.

FIG. 6 shows an example of a facility for receiving dust collected by the cyclone 30. A receiving tank 31 is connected to a lower portion of the cyclone 30 via a conduit 35, and a shutoff valve is provided at a lower portion thereof. The equalizing tank 32 and the blowing tank 33 are connected in order via conduits 36 and 37 having 38a and 38b, respectively, and a pneumatic device 34 having a blowing nozzle is connected to a lower portion of the blowing tank 33 via a shutoff valve 38c. Have been.

In such a facility, the dust collected by the cyclone 30 falls directly into the receiving tank 31, and when a predetermined amount of the dust has accumulated in the receiving tank 31, the shutoff valves 38a and 38b are opened and closed. Pressure tank 32
Is fed to the blowing tank 33 via the slag, where the pressure is increased to a blowing pressure higher than the pressure in the smelting reduction furnace system, and then supplied (injected) from the pneumatic device 34 to the smelting reduction furnace side.

[0006]

By the way, the dust receiving facility provided below the cyclone 30 as described above is intended to smoothly discharge the dust in the receiving tank 31 into the equalizing tank 32 below. For the purpose, a cyclone 30 is provided to supply aeration gas into the receiving tank 31 and to prevent dust from entering the mounting seat of various measuring means attached to the receiving tank 31 or the like and hindering the measurement. The duct section between the receiving tank 31 and the equalizing tank 32, which prevents the accumulation of dust inside the expansion section (part of the conduit 35) connecting the receiving tank 31 and maintains the function of the expansion section, To prevent dust from adhering and accumulating on the provided shut-off valve (seal valve) and maintain the function of the shut-off valve, the It is supplying the purge gas.

However, this equipment has a serious problem that the aeration gas and the purge gas blow up from the lower end of the cyclone into the inside thereof and wind up fine ore, so that the collection efficiency of the cyclone is remarkably deteriorated. Therefore, an object of the present invention is to solve such problems of the prior art, to prevent aeration gas and purge gas blown into a dust receiving facility below the cyclone from blowing up into the cyclone, and to collect high dust in the cyclone. An object is to provide equipment capable of obtaining efficiency.

[0008]

The features of the present invention for solving such a problem are as follows. [1] An exhaust gas path for guiding exhaust gas from a fluidized bed type pre-reduction furnace in a smelting reduction facility, a cyclone provided in the exhaust gas path for collecting dust in exhaust gas, The collected dust falls, a receiving tank for receiving the dust, and dust collecting equipment having dust blowing means for blowing the dust in the receiving tank into the smelting reduction furnace,
A pre-reduction furnace discharge, wherein a gas discharge path A is provided for communicating the gas in the receiving tank to the exhaust gas path on the downstream side of the cyclone so as to escape to the exhaust gas path on the downstream side of the cyclone. Dust recovery equipment from gas.

[2] In the dust collection facility of the above [1],
The dust blowing means includes a pressure equalizing tank connected to a lower part of the receiving tank, a blowing tank connected to a lower part of the pressure equalizing tank, and a pneumatic device connected to a lower part of the blowing tank. A gas discharge path B communicating between the equalizing tank and the exhaust gas path or gas discharge path A on the downstream side of the cyclone for releasing gas in the pressure tank to an exhaust gas path or gas discharge path A on the downstream side of the cyclone. Dust recovery equipment from exhaust gas from the preliminary reduction furnace, which is provided.

[3] In the dust collection facility of the above [1],
The dust blowing means comprises a plurality of blowing tanks connected in parallel to a lower part of the receiving tank, and a pneumatic device connected to a lower part of each of the blowing tanks, and the gas in each of the blowing tanks is supplied to the cyclone downstream side. Pre-reduction characterized by providing a gas discharge path B for communicating between each blowing tank and a discharge gas path or gas discharge path A on the downstream side of the cyclone in order to escape to the exhaust gas path or gas discharge path A. Dust recovery equipment from furnace exhaust gas.

[4] The dust recovery equipment according to any one of [1] to [3] above, wherein a dust removal device is provided in an exhaust gas path downstream of the cyclone, wherein the gas discharge paths A and / or Alternatively, one end of the gas exhaust path B is connected to an exhaust gas path on the downstream side of the dust remover, wherein the facility for collecting dust from exhaust gas from a preliminary reduction furnace is provided. [5] The dust recovery equipment according to any one of [1] to [3] above, wherein a dust removal device is provided in an exhaust gas path downstream of the cyclone, wherein the gas discharge path A and / or the gas discharge path Dust recovery equipment from pre-reduction furnace exhaust gas, wherein one end of the path B is connected to an exhaust gas path on the upstream side of the dust removing device.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention, wherein 1 is a smelting reduction furnace, 2 is a fluidized bed type pre-reduction furnace,
Reference numeral 3 denotes an exhaust gas path for guiding exhaust gas discharged from the preliminary reduction furnace, reference numeral 4 denotes a cyclone for dust collection provided in the middle of the exhaust gas path 3, and reference numeral 5 denotes an exhaust gas path 3 downstream of the cyclone. The dust removing device (in this embodiment, a venturi scrubber) 6 is a mist separator provided further downstream thereof.

In such a facility, the high-temperature exhaust gas containing CO and H ₂ generated in the smelting reduction furnace 1 is introduced into the pre-reduction furnace 2 through the gas conduit 15, and while the iron ore in the furnace is fluidized, the pre-reduction is performed. I do. Of the iron ores (usually having a particle size of 8 mm or less) preliminarily reduced in the prereduction furnace 2, those having a relatively coarse particle size are extracted by dropping under their own weight through an extraction pipe 16 below the fluidized bed, and are extracted.
7, is supplied to the smelting reduction furnace 1 side.

On the other hand, the fine ore is discharged from the upper part of the pre-reduction furnace 2 together with the exhaust gas to the outside of the furnace, and most of the fine ore is collected as dust by the cyclone 4 and then provided at the lower part of the cyclone 4. The dust is collected by the dust receiving facility and finally supplied to the smelting reduction furnace 1 through the supply path 18 (injection). The exhaust gas that has passed through the cyclone 4 is dust-removed by a dust removal device 5 composed of a venturi scrubber, and after the mist is removed by a mist separator 6, the exhaust gas is discharged outside the system.

The dust receiving equipment provided below the cyclone 4 has a receiving tank 7 connected to the lower part of the cyclone 4 via a conduit 11, and dust blowing means connected to a lower part of the receiving tank 7. And
The dust collected by the cyclone 4 falls directly into the receiving tank 7 through the conduit 11, and is supplied to the smelting reduction furnace through the dust blowing means.

In this embodiment, the dust blowing means includes a pressure equalizing tank 8 connected to a lower part of the receiving tank 7, a blowing tank 9 connected to a lower part of the pressure equalizing tank 8,
Pneumatic device 10 connected to the lower part of this blowing tank 9
The shut-off valve 1 is provided between the receiving tank 7 and the equalizing tank 8 and between the equalizing tank 8 and the blowing tank 9.
It is connected by conduits 12 and 13 provided with 4a and 14b, and a shutoff valve 14c is provided between the blowing tank 9 and the air supply device 10.

A pressurized gas supply pipe (not shown) and a pressurized gas discharge pipe (not shown) are connected to the equalizing tank 8 and the blowing tank 9, respectively, so that the inside of each tank can be pressurized and depressurized. I am doing it. The pneumatic device 10 has a blowing nozzle (not shown) to which pneumatic gas is supplied, and pneumatically supplies dust to the smelting reduction furnace 1 through a supply path 18.

In such a dust receiving facility, when a certain amount of dust accumulates in the receiving tank 7, the shut-off valve 14a is opened to make the dust equal to the pressure in the cyclone section. Let fall inside. Next, the shutoff valve 14a is closed, and pressurized gas is supplied into the equalizing tank 8 to pressurize the gas. After that, the shutoff valve 14b is opened to cause dust to fall into the blowing tank 9 which is also in a pressurized state. Next, the shutoff valve 14b is closed and the shutoff valve 14c is opened to supply the dust in the blow-in tank 9 to the pneumatic device 10.

In the above-mentioned equipment, a gas discharge path A is provided for communicating between the receiving tank 7 and the exhaust gas path 3 on the downstream side of the cyclone, and the gas in the receiving tank 7 is transferred by the gas discharging path A to the cyclone. The exhaust gas can be released to the exhaust gas path 3 on the downstream side. The gas discharge path A of the present embodiment includes a receiving tank 7 and a dust removing device 5.
(And the mist separator 6) and the exhaust gas path 3 on the downstream side.

By providing such a gas discharge path A, the gas in the receiving tank 7 is supplied to the discharge gas path 3 downstream of the cyclone.
By escaping into the (lower pressure section than the cyclone 4), the pressure in the receiving tank 7 becomes lower than the pressure in the cyclone 4, so that the direction of the gas flow is always changed to the cyclone 4 →
The receiving tank 7 can be used. This reliably prevents the purge gas and the aeration gas supplied to the dust receiving facility from blowing up from the lower end of the cyclone 4 to the inside thereof.

When only the gas discharge path A is provided, the shutoff valve 14 between the equalizing tank 8 and the receiving tank 7 is provided.
When “a” is opened, the amount of gas flowing through the gas discharge path A increases at once, so that the pressure in the receiving tank 7 increases, and the gas may flow backward from the receiving tank 7 to the cyclone 4 side. Therefore, a gas discharge path B is provided between the equalizing tank 8 and the exhaust gas path 3 on the downstream side of the cyclone, and a gas in the equalizing tank 8 is transferred to the exhaust gas path 3 on the downstream side of the cyclone. So that you can miss it.

The gas discharge path B in this embodiment communicates between the pressure equalizing tank 8 and the discharge gas path 3 downstream of the dust removing device 5 (and the mist separator 6).
Further, the gas discharge path B is joined to the gas discharge path A as shown in the path b in the figure, and the pressure equalizing tank 8 and the gas discharge path A
May be provided so as to communicate between them. In this case,
Gas discharge path A downstream from the connection of gas discharge path B
It is preferable to increase the diameter of the conduit. Note that a shutoff valve 19 is provided in the gas discharge path B in order to maintain the pressure when the inside of the equalizing tank 8 is pressurized. In the middle of the gas discharge path A and the gas discharge path B, the flow control valve 20,
21 is provided to control the pressure of the receiving tank 7 and the pressure equalizing tank 8.

By providing such a gas discharge path B and allowing the gas in the pressure equalizing tank 8 to escape to the exhaust gas path 3 downstream of the cyclone, the shut-off valve 14a between the pressure equalizing tank 8 and the receiving tank 7 is opened. Even when it is opened, the amount of gas flowing through the gas discharge path A does not increase at a stroke, whereby the direction of gas flow can always be changed from the cyclone 4 to the receiving tank 7.

The pressure equalizing tank 8 provided by the gas discharge path B
The discharge of the gas in the chamber may basically be performed only when the shut-off valve 14a between the equalizing tank 8 and the receiving tank 7 is opened. Therefore, in a normal state, the shut-off valve 19 of the gas discharge path B is closed. The shut-off valve 19 may be opened at the same time as the shut-off valve 14a is opened.

The gas that escapes to the exhaust gas path 3 through the gas exhaust path A and the gas exhaust path B contains dust. In the present embodiment, this gas is discharged to the gas exhaust path downstream of the dust removal device 6. In order to discharge the gas to 3, it is preferable to remove dust from the gas at some stage. FIG. 5 shows a dust removing mechanism for this purpose, in which a small cyclone 25 is provided at the connection part of the tanks (receiving tank 7, equalizing tank 8) of the gas discharge paths A and B.

The cyclone 25 is fixed to the tank body so that the dust outlet 250 at the lower end is located inside the tank body (receiving tank 7 or pressure equalizing tank 8). One end of the conduit 26a constituting the gas discharge path (the gas discharge path A or the gas discharge path B) is connected to the tank main body, the other end is connected to the upper part of the cyclone 25, and the end of the conduit 26b is connected. The cyclone 25 is inserted into the inside from the upper end.

The dust outlet 25 at the lower end of the cyclone
0 is provided with a check valve 27 to prevent gas from flowing into the cyclone from the dust discharge port 250. As shown in FIG. 5, for example, the check valve 27 bends the lower end of the dust discharge port 250 obliquely downward, and provides an openable and closable valve body 28 at the opening thereof. Thereby, a structure in which the dust outlet 250 is closed can be adopted. According to such a structure, a certain amount of dust accumulates at the bottom of the cyclone 25, and the weight of the dust gives a moment to the valve body 28 in a direction to open the valve body 28. 28, the dust is discharged from the dust discharge port 250. After the dust discharge, the dead weight of the valve body 28 and the dust discharge port 2
The valve body 28 is closed by the pressure of the gas which is going to flow into 50.

FIG. 2 shows another embodiment of the present invention, in which the gas discharge paths A and B are connected between the receiving tank 7, the equalizing tank 8 and the exhaust gas path 3 upstream of the dust removing device 5. It is provided to perform. According to such an embodiment, since the gas in the receiving tank 7 and the equalizing tank 8 is released to the gas discharge path 3 on the upstream side of the dust removing device 5 through the gas discharge paths A and B, the gas contains dust. Figure 5
There is an advantage that it is not necessary to particularly provide a dust removing mechanism as shown in FIG. However, from the viewpoint of preventing the accumulation of dust inside the gas discharge paths A and B, providing a dust removing mechanism as shown in FIG.

In this embodiment, the gas discharge paths A and B
The position of the exhaust gas path 3 on the upstream side of the dust remover 5 to which the gas exhaust path A and the gas exhaust paths A and B are connected in the embodiment of FIG. Since the difference is small, the gas discharge paths A and B are used to smoothly discharge the gas through the gas discharge paths A and B.
Ejectors 22 and 23 are provided in the middle of the tank so that gas on the tank side can be drawn toward the exhaust gas path 3.

Also in the present embodiment, the gas discharge path B is joined to the gas discharge path A as shown by a path b in the figure, so that the pressure equalizing tank 8 and the gas discharge path A are connected. It may be provided. In this case, the gas discharge path B
It is preferable to increase the diameter of the conduit in the gas discharge path A downstream of the connecting portion. Since the other configuration is the same as that of the embodiment shown in FIG. 1, the same reference numerals are given and the detailed description is omitted.

Also in this embodiment, a gas discharge path A is provided to release gas in the receiving tank 7 to the discharge gas path 3 downstream of the cyclone (lower pressure section than the cyclone 4), similarly to the embodiment of FIG. Accordingly, the pressure in the receiving tank 7 becomes lower than the pressure in the cyclone 4, so that the gas flow direction can always be changed from the cyclone 4 to the receiving tank 7. This reliably prevents the purge gas and the aeration gas supplied to the dust receiving facility from blowing up from the lower end of the cyclone 4 to the inside thereof.

Further, by providing a gas discharge path B to release the gas in the pressure equalizing tank 8 to the discharge gas path 3 downstream of the cyclone, the shut-off valve 14a between the pressure equalizing tank 8 and the receiving tank 7 is opened. Even in this case, the amount of gas flowing through the gas discharge path A does not increase at a stroke, whereby the flow direction of the gas can always be changed from the cyclone 4 to the receiving tank 7.

FIG. 3 shows another embodiment of the present invention, in which the equalizing tank as in the embodiment of FIGS. 1 and 2 is not provided, and the branch pipes 240A, 240A and 2B are provided below the receiving tank 7.
The two blowing tanks 9A and 9B are connected in parallel via a conduit 24 provided with the blowing tanks 40A and 40B, and pneumatic devices 10A and 10B are provided below the respective blowing tanks 9A and 9B.
Are connected.

The conduit 24 immediately below the receiving tank 7 is provided with a shut-off valve 14d, and the branch pipes 240A and 240B below the conduit are also provided with shut-off valves 14e ₁ and 14e _2.
Are provided respectively. In addition, blow tank 9
A, shutoff valves 14c _1, 14c ₂ is also provided between the 9B and in their lower feed feel each connected device 10A, 10B.

A pressurized gas supply pipe (not shown) and a pressurized gas discharge pipe (not shown) are connected to the blowing tanks 9A and 9B, respectively, so that the inside of each tank can be pressurized and depressurized. ing. Each of the pneumatic devices 10A and 10B has a blowing nozzle (not shown) to which pneumatic gas is supplied.
Pneumatic supply to the side.

[0036] In such a dust receiving equipment, when it accumulated a degree of the amount of dust in the receiving tank 7, the pressure of the cyclone unit dust by opening the shutoff valve 14b and shut-off valve 14e ₁ or shutoff valve 14e ₂ And dropped into the blowing tank 9A or the blowing tank 9B with almost the same pressure,
Dust is stored in each blowing tank 9A, 9B.
And each blowing tank 9A or blowing tank 9
When paying out the dust from of B, the blowing tank into a pressurized state with shutoff valve 14c (14c ₁ or 14c ₂₎
To release the dust in the blowing tank
(10A or 10B).

Also in the above-mentioned equipment, a gas discharge path A is provided for communicating between the receiving tank 7 and the exhaust gas path 3 on the downstream side of the cyclone, and the gas in the receiving tank 7 is supplied by the gas discharging path A. The exhaust gas can be released to the exhaust gas path 3 downstream of the cyclone. The gas discharge path A of the present embodiment includes a receiving tank 7 and a dust removing device 5.
(And the mist separator) and the exhaust gas path 3 on the downstream side.

Also in this embodiment, a gas exhaust path A is provided to release gas in the receiving tank 7 to the exhaust gas path 3 downstream of the cyclone (lower pressure section than the cyclone 4) as in the embodiment of FIG. Accordingly, the pressure in the receiving tank 7 becomes lower than the pressure in the cyclone 4, so that the gas flow direction can always be changed from the cyclone 4 to the receiving tank 7. This reliably prevents the purge gas and the aeration gas supplied to the dust receiving facility from blowing up from the lower end of the cyclone.

Further, in the case of providing only the gas discharge path A includes a tank 9A blowing a receiving tank 7, when opening the shutoff valve 14d and cut-off valve 14e ₁ or shutoff valve 14e ₂ between 9B, gas Since the amount of gas flowing through the discharge path A increases at once, the pressure in the receiving tank 7 increases, and the gas may flow backward from the receiving tank 7 to the cyclone 4 side. Therefore, a gas discharge path B is provided between each blowing tank 9A, 9B and the exhaust gas path 3 on the downstream side of the cyclone so as to communicate between them, and each blowing tank 9A, 9B is provided.
The inside gas can be released to the exhaust gas path 3 on the downstream side of the cyclone.

The gas discharge path B of the present embodiment communicates between the blowing tanks 9A and 9B and the discharge gas path 3 downstream of the dust remover 5 (and the mist separator). Further, the gas discharge path B is joined to the gas discharge path A as shown in a path b in the figure, and each of the blowing tanks 9A, 9
A connection may be provided between B and the gas discharge path A. In this case, it is preferable that the diameter of the conduit is larger in the gas discharge path A downstream than the connection portion of the gas discharge path B. Note that shutoff valves 19A and 19B are provided in the gas discharge paths B corresponding to the blow tanks 9A and 9B in order to maintain the pressure when the blow tanks 9A and 9B are pressurized. Further, flow control valves 20 and 21 are provided in the gas discharge path A and the gas discharge path B to control the pressure of the receiving tank 7 and the blowing tanks 9A and 9B.

The gas discharge path B of this embodiment is obtained by joining the gas discharge paths B from the blowing tanks 9A and 9B and connecting the combined single path to the exhaust gas path 3 or the gas discharge path A. There are blow tanks 9A and 9B
The exhaust gas path B from the exhaust gas path 3
Alternatively, it may be connected to the gas discharge path A.

By providing such a gas discharge path B and allowing the gas in the blowing tanks 9A and 9B to escape to the exhaust gas path 3 downstream of the cyclone, the blowing tanks 9A and 9B are discharged.
B and the shut-off valve 14d and the shut-off valve 14 between the receiving tank 7
e ₁ or shutoff valve 14e ₂ open and to without such increases once the amount of gas flowing through the gas discharge path A also upon which constantly cyclone in the direction of gas flow by 4 →
The receiving tank 7 can be used.

The gas discharged from the blow-in tanks 9A and 9B by the gas discharge path B is basically discharged by a shut-off valve 14d between the blow-in tanks 9A and 9B and the receiving tank 7.
Well shut-off valve 14e ₁ or shutoff valve 14e ₂ be performed only when the opening and the gas discharge path B in this order normally
Shutoff valves 19A of, kept closed and 19B, and opens the shut-off valve 14d and cut-off valve 14e ₁ or shutoff valve 14e ₂ and may be opened shut-off valve 19A or shut-off valve 19B simultaneously.

When a plurality of blowing tanks 9 are connected in parallel below the receiving tank 7 as in the present embodiment, the number of the blowing tanks 9 is arbitrary. Since the other configuration is the same as that of the embodiment shown in FIGS. 1 and 5, the same reference numerals are given and the detailed description is omitted.

FIG. 4 shows another embodiment of the present invention, in which the gas discharge paths A and B are received in the receiving tank 7, the blowing tanks 9A and 9B, and the exhaust gas path 3 on the upstream side of the dust removing device 5.
It is provided to communicate between According to such an embodiment, the receiving tank 7 and the blowing tank 9
In order to allow the gas in A and 9B to escape to the gas discharge path 3 on the upstream side of the dust removing device 5 through the gas discharge paths A and B, a dust removing mechanism as shown in FIG. 5 is provided even if the gas contains dust. There is an advantage that there is no need. However, from the viewpoint of preventing the accumulation of dust inside the gas discharge paths A and B, providing a dust removing mechanism as shown in FIG.

In this embodiment, as in the embodiment shown in FIG. 2, ejectors 22 and 23 are provided in the middle of gas discharge paths A and B in order to smoothly discharge gas through gas discharge paths A and B. Provide the gas on the tank side to the exhaust gas path 3
So that you can pull it to the side. Also in this embodiment, the gas discharge path B is merged with the gas discharge path A as shown by a path b in the figure, and the blowing tank 9A,
9B and the gas discharge path A may be provided so as to communicate with each other. In this case, it is preferable that the diameter of the conduit is larger in the gas discharge path A downstream than the connection portion of the gas discharge path B. Since the other configuration is the same as that of the embodiment shown in FIG. 3, the same reference numerals are given and the detailed description is omitted.

Also in this embodiment, similarly to the embodiment of FIG. 3, a gas discharge path A is provided to release the pressure in the receiving tank 7 to the discharge gas path 3 downstream of the cyclone (a lower pressure section than the cyclone 4). Accordingly, the pressure in the receiving tank 7 becomes lower than the pressure in the cyclone 4, so that the gas flow direction can always be changed from the cyclone 4 to the receiving tank 7. This reliably prevents the purge gas and the aeration gas supplied to the dust receiving facility from blowing up from the lower end of the cyclone 4 to the inside thereof.

Further, by providing a gas discharge path B to release the gas in the blow-in tanks 9A and 9B to the discharge gas path 3 downstream of the cyclone, a shut-off valve 14d between the blow-in tanks 9A and 9B and the receiving tank 7 is provided. And shutoff valve 14e ₁
Or gas discharge path A even when opening the shut-off valve 14e ₂
The amount of gas flowing through the tank does not increase all at once, whereby the flow direction of the gas can always be changed from the cyclone 4 to the receiving tank 7. In each of the above embodiments, the dust removing device 5 provided in the exhaust gas path 3 may be constituted by another type of dust removing device such as a bag filter.

In the equipment of the present invention, there is no particular limitation on the amount of gas that escapes to the exhaust gas path 3 downstream of the cyclone through the gas exhaust paths A and B. %, So that the dust collection efficiency of the cyclone 4 is about 10% lower than that of the related art.
% Improvement. When the amount of gas released through the gas discharge paths A and B increases, the load on the facilities such as pipes increases accordingly. Therefore, it is not preferable to increase the amount of released gas more than necessary.

[0050]

According to the dust recovery equipment of the present invention described above, the gas flow can always be maintained from the cyclone toward the receiving tank, and the purge gas and the aeration gas blown into the dust receiving equipment below the cyclone can be maintained in the cyclone. Since it is reliably prevented from blowing up inside, the dust collection efficiency in the cyclo can be dramatically improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a dust collection facility of the present invention.

FIG. 2 is an explanatory view showing another embodiment of the dust collection equipment of the present invention.

FIG. 3 is an explanatory view showing another embodiment of the dust collection equipment of the present invention.

FIG. 4 is an explanatory view showing another embodiment of the dust collection equipment of the present invention.

FIG. 5 is a cross-sectional view showing an example of a dust removing mechanism for removing gas discharged through gas discharge paths A and B in the dust recovery equipment of the present invention.

FIG. 6 is an explanatory view showing a part of a conventional dust collection facility.

[Explanation of symbols]

1 ... smelting reduction furnace, 2 ... preliminary reduction furnace, 3 ... exhaust gas path,
4 cyclone, 5 dust remover, 6 mist separator, 7 receiving tank, 8 equalizing tank, 9, 9A, 9
B: blow tank, 10, 10A, 10B: pneumatic device, 11, 12, 13 ... conduit, 14a, 14b, 14
_{c, 14c 1, 14c 2,} 14d, 14e 1, 14e 2 ... shutoff valve, 15 ... gas conduit 16 ... discharge pipe, 17 ... supply path, 18 ... supply path, 19, 19A, 19B ... shutoff valve, 20, 21: flow control valve, 22, 23: ejector,
Reference numeral 24: conduit, 25: cyclone, 26a, 26b: conduit, 27: check valve, 28: valve body, 240A, 240B ...
Branch pipe, 250 ... dust outlet, A, B ... gas discharge path

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Mitsuhiro Yamanaka, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Katsuhiro Iwasaki 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan (72) Inventor Susumu Isozaki, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan In-tube (72) Inventor Masahiro Kawakami 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan Inside Steel Pipe Co., Ltd.

Claims (5)

[Claims] An exhaust gas path for guiding exhaust gas from a fluidized bed type pre-reduction furnace in a smelting reduction facility; a cyclone provided in the exhaust gas path for collecting dust in the exhaust gas; Dust collected by the cyclone falls, a dust collecting facility having a receiving tank for receiving the dust, and dust blowing means for blowing the dust in the receiving tank into the smelting reduction furnace; Dust from exhaust gas of a pre-reduction furnace characterized by having a gas exhaust path A communicating between a receiving tank and an exhaust gas path downstream of the cyclone for allowing gas to escape to an exhaust gas path downstream of the cyclone. Collection equipment. 2. A dust equalizing tank connected to a lower portion of a receiving tank, a blowing tank connected to a lower portion of the equalizing tank, and a pneumatic device connected to a lower portion of the blowing tank. An equalizing tank and an exhaust gas path or gas discharge path A on the downstream side of the cyclone for allowing gas in the pressure equalizing tank to escape to an exhaust gas path or gas exhaust path A on the downstream side of the cyclone.
2. A facility for collecting dust from exhaust gas from a preliminary reduction furnace according to claim 1, wherein a gas discharge path B is provided for communication between the exhaust gas from the pre-reduction furnace. 3. The dust blowing means comprises: a plurality of blowing tanks connected in parallel to a lower portion of the receiving tank; and a pneumatic device connected to a lower portion of each of the blowing tanks. A gas discharge path B communicating between each blowing tank and the exhaust gas path or gas discharge path A on the downstream side of the cyclone for releasing gas to an exhaust gas path or gas discharge path A on the downstream side of the cyclone is provided. The facility for collecting dust from exhaust gas of a preliminary reduction furnace according to claim 1. 4. A dust recovery facility provided with a dust removing device in an exhaust gas path downstream of a cyclone, wherein one end of a gas exhaust path A and / or a gas exhaust path B is connected to an exhaust gas path downstream of the dust removing apparatus. 4. The facility for collecting dust from exhaust gas of a pre-reduction furnace according to claim 1, 2 or 3. 5. A dust recovery facility in which a dust removal device is provided in an exhaust gas path downstream of a cyclone, wherein one end of a gas discharge path A and / or a gas discharge path B is connected to an exhaust gas path upstream of the dust removal apparatus. 4. The facility for collecting dust from exhaust gas of a pre-reduction furnace according to claim 1, 2 or 3.