JPH0257627A - Method and apparatus for collecting dust in blast furnace - Google Patents

Abstract

PURPOSE:To effectively collect dust generating accompanied with molten iron tapping in blast furnace by collecting the generated dust in the molten iron from the molten iron tapping hole in the blast furnace to a molten iron receiving vessel by assembling local dust collectors, a cut-off gas flow injecting device and a blast furnace building dust collector. CONSTITUTION:The molten iron tapping from the blast furnace 1 is executed at the molten iron tapping hole 2 and the tapped molten iron stream A is received into the molten iron receiving vessel 5 through a molten iron trough 3 and tilting trough 4. Then, the trough covers 6a, 6b are arranged on the molten iron trough 3 and the cut-off gas flow 11 is injected to the dust containing gas flows B, C around the molten iron tapping hole 2 from the cut-off gas flow injecting device 12, and the generated dust is sucked with local dust collecting duct 8A in the local dust collector 8. Further, the generated dust around the trough cover 6b is introduced to the local dust collecting duct 7a in the local dust collector 7 and the generated dust at the other opening part is collected at a suction hood 10A in the blast furnace building dust collector 10. By this method, flowing-out of the dust into the blast furnace building is reduced and power for building dust collector is saved.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method and apparatus for effectively collecting dust generated during tapping of a blast furnace.

<Prior art> During tapping of a blast furnace, a large amount of dust is generated from the taphole.
For the safety of on-site operations, dust is collected from the taphole, hot metal trough, sloped trough, and tailings trough. However, at the taphole, where a large amount of dust is generated, there is a dedicated area called castbed dust collection. It is common practice to install a dust collection suction hood.

In addition, the tapping speed is not constant and the amount of dust generated changes, and the amount of dust generated is especially large at the beginning and end of tapping, and dust may leak into the building from the above-mentioned casthouse dust collection system. Therefore, a dust collection suction hood is installed in the blast furnace building.

However, if a casthouse dust collection system and a building dust collection system are installed together in this way, if the tapping time is medium and the amount of dust generated is small, it will waste electricity, etc. When the amount of dust becomes large, it becomes necessary to install additional dust collectors, which is uneconomical.

Therefore, as a countermeasure to the above, it is possible to isolate the dust generating part from the outside air using pressurized gas, limit the dust collection area, or assist the dust suction power. Conventionally, the following methods have been proposed. .

(i) To prevent hot metal and slag from oxidizing due to contact with the atmosphere outside the JP-A No. 52-111402 furnace, an inert gas (N2) jet and suction port is provided near a predetermined position to form a gas curtain. How to do it.

(ii) Japanese Unexamined Patent Publication No. 55-164006 A method in which the exhaust of cooling air from a blast furnace hot metal trough is made into an air curtain and sucked into a suction port of a dust collection duct near the taphole.

(iii > JP-A-55-145109 A method in which the cooling gas from a hot stove, which is one of the blast furnace facilities, is sent through a duct into the hot metal gutter hood to assist the dust collector.

(iv) Japanese Patent Application Laid-Open No. 54-93608 A method of providing air jet ports and suction ports across the width of a hot metal trough or slag trough to form an air curtain and sealing off fumes.

<Problems to be Solved by the Invention> However, conventional methods that utilize a special suction port or exhaust for pressurized gas require a long duct, which in reality requires a huge amount of cost. Met.

Furthermore, in some cases, the flow velocity of dust-containing gas from the taphole reaches several tens of meters per second, and conventional methods may not be able to prevent dust from flowing into the blast furnace building.

This invention was made in order to solve the above-mentioned problems, and its purpose is to prevent dust from flowing into the blast furnace building with a relatively simple structure that does not require a special suction port or a long duct. It is an object of the present invention to provide a method and device for collecting blast furnace dust, which can reduce the amount of dust collected and save power during building dust collection.

<Means for Solving the Problems> In the blast furnace dust collection method according to the present invention, as shown in Figs. The dust generated in the process leading to step 5 is collected by local dust collection in front of the tap hole 2, a cutoff airflow 11 formed in front of this local dust collection part, and a separation between the taphole 2 and the cutoff airflow 11.
Dust is collected by a combination of one or both of the opposing airflows 14 formed between the taphole 2 and the dust-containing airflow from the taphole 2, and the blast furnace building dust collection.

Further, the device according to the present invention is used to carry out the method described above, and includes a local dust collector 8 provided in front of the tap hole 2 of the blast furnace 1, and a local dust collector 8 provided in front of the tap hole 2 of the blast furnace 1; A cutoff airflow injection device 12 that injects a cutoff airflow 11 that can block the dust-containing airflow from the taphole 2, and a cutoff airflow injection device 12 that is arranged between the local dust collector 8 and the cutoff airflow injection device 12 to prevent dust-containing airflow from the taphole 2. It is composed of an opposing airflow injection device 13 that injects an opposing airflow 14 that is substantially opposite to the airflow, and a blast furnace building dust collector 10 installed in the blast furnace building.

<Operation> In Fig. 1, tapping from the blast furnace 1 is performed from the taphole 2, and the tapped hot metal flow passes through the hot metal trough 3 and the tilting trough 4, and is stored in the pig iron receiving vessel 5, and the hot metal is Dust generated from the flow, etc. is collected through the gutter covers 6a, 6b, etc., and is transferred to the local dust collection ducts l-7A, 8.
In addition, dust generated from around the hot metal flow A in the open area between the taphole 2 and the gutter cover 6a is generally guided to the duct 8A of the local dust collector 8 (the deck 9). A dust collection port is provided in the ceiling) and the suction hood IOA of the blast furnace building dust collector 10 is used to collect dust.

During the period of regular tapping, the above-mentioned method usually collects dust sufficiently, but it is not always sufficient at the start and end of tapping.

This is because a shedding machine (not shown) is located in front of the tap hole 2 when tapping starts, and a Malad gun is located in front of the tap hole 2 when tapping ends, so the gutter cover 6a should be removed in advance. This is because the hot metal and the taphole filler react violently around the taphole 2, and the amount of dust and smoke generated is greater than during regular tapping.

In addition, the gas ejected from the taphole is affected by the internal pressure of the blast furnace, and its initial velocity generally reaches several tens of meters per second. Most of the dust was collected using the building's dust collection suction hood IOA.

The present invention has been made mainly to effectively suppress the dust and smoke generated at the start and end of tapping by local dust collection, as shown in Fig. 2. In response to the generation of airflows B and C, by injecting the blocking airflow 11, the dust-containing airflow C' is blocked to be as small as possible, and the dust-containing airflow newly branched from C is used for local dust collection. Suction into hood 8A. This makes it possible to reduce the amount of dust-containing airflow that must be sucked into the building dust collection hood IOA.

FIG. 3 shows an embodiment in which local dust collection is further strengthened than the embodiment shown in FIG.

C' and D are not shown. This allows the direction of the cutoff airflow 11 to be tilted toward the taphole 2 side within a range up to an angle α with respect to the vertical direction, and also allows the cutoff airflow injection device 1
2 and the local dust collection duct 8A.
is installed, and a counter air flow 14 is injected so as to be substantially opposite to the dust-containing air flow from the tap hole 2.

The opposing airflow 14 can weaken the flow velocity of the dust-containing airflows B and C toward the blocking air fLll, and can improve the local dust collection effect.

Further, the angle β between the tap hole 2 and the opposing airflow 14 is variable by tilting the opposing airflow injection device 13.

The angle α is also variable by tilting the blocking airflow injection device 12. The reason why the angles α and β are made variable is that it is advantageous to be able to exhibit the maximum blocking effect by changing the angles α and β depending on the shape of the taphole 2, the flow rate or flow rate of the hot metal flow, etc.

In addition, as shown in FIG. 1, the cutoff airflow injection device 12 has an injection port 12A divided into a plurality of parts, which are connected to a duct 12C via an air volume control damper 12B, and the injection flow rate is adjusted by the opening degree of the damper 12B. For example, it is also possible to partially increase the air volume only at the ejection port located near the extension of the tap hole 2. In addition, when the number of spout ports 12A is one, as shown in FIG.
It can also be made into a double slit.

Further, the opposed air current injection device 13 may have one or multiple ejection ports.

<Example of implementation> This uses the split type jet nozzle 12A shown in Fig. 2, and blocks the dust-containing airflow C-C'' from the vicinity of the taphole 2 with the blocking airflow 11, allowing the amount of C'' to be reduced. In addition, in the embodiment shown in Fig. 3, the angle α of the cutoff airflow II with respect to the vertical direction is tilted by 10° toward the taphole 2 side, and the taphole The angle β between 2 and the opposing airflow 14 is 42
°. These results are listed in the table below.

As is clear from this table, according to the present invention, power consumption can be reduced more than in the conventional case, and the embodiment (b) can achieve greater savings.

<Effects of the Invention> As mentioned above, according to the present invention, since localized dust collection is performed by blocking airflow and opposing airflow, there is no need for a special suction port or a long duct, and the structure is relatively simple and requires little investment. This reduces the outflow of dust into the blast furnace building, making it possible to save electricity for dust collection in the building.

The present invention is applicable not only to the blast furnace taphole, but also to dust collection around the slag taphole or the converter main body, for example, dust collection from dust-containing airflow ejected from the gap in the hood.

[Brief explanation of the drawing]

1 and 2 are overall schematic diagrams showing one embodiment of the present invention,
FIG. 3 is a schematic diagram showing a modified example, and FIG. 4 is a schematic diagram showing various cross-sectional patterns of the blocked airflow. 1...Blast furnace, 2...Tapping port, 3...Hot metal trough, 4...
...Tilt gutter, 5...Pigtail receiving container, 6...Gutter cover, 7
．． 8... Local dust collector, 7A, 8A... Duct, 9
...Deck, 10...Blast furnace building dust collector, 10A.
... Suction hood, 11... Blocking airflow, 12... Blocking airflow injection device, 13... Opposed airflow injection device, 14...
Opposed airflow.

Claims (2)

[Claims] (1) Dust generated during the process of hot metal reaching the pig iron receiving vessel from the taphole of the blast furnace through the hot metal trough is collected by local dust collection in front of the taphole and by a blocking airflow formed in front of this local dust collection area. , the dust is collected by a combination of one or both of the opposing airflows formed between the taphole and the cutoff airflow so as to substantially oppose the dust-containing airflow from the taphole, and blast furnace building dust collection. A blast furnace dust collection method characterized by: (2) A local dust collector installed in front of the taphole of the blast furnace, and a blocking airflow jet that is placed in front of the local dust collector and injects a blocking airflow capable of blocking the dust-containing airflow from the taphole. a counter air flow injection device that is disposed between the local dust collector and the cutoff air flow injection device and injects a counter air flow that is substantially opposite to the dust-containing air flow from the taphole; A blast furnace dust collector comprising: a blast furnace building dust collector;