JPS6140004B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blast furnace casthouse dust collection system, and more specifically, all dust gases generated during the tapping operation during blast furnace operation are guided to the upper part of the casthouse building and collected by an electrostatic precipitator. Regarding dust collection equipment that makes it possible to remove dust.

Blast furnace casthouse dust collection generally consists of a combination of primary dust collection and secondary dust collection. The primary dust collection equipment normally collects dust generated from the taphole, big culvert, skinmer, hot metal trough, tilting trough, etc. during tapping locally near the source, and the secondary dust collection equipment A huge amount of smoke (commonly known as abnormal dust generation) generated from the taphole at the beginning or end of the tapping period is stored in the building and collected. Currently, the most widely used method is this method, in which the dust gas generated from each part of the dust generating section is forcibly sucked in using large exhaust fans, and the smoke is purified using bag filters (dust collectors).

FIG. 1 shows the above-mentioned dust collection system. 1 is a blast furnace, and during normal tapping, the taphole,
The dust gas generated from the big gutter, skimmer, hot metal slag gutter, hot metal slag pouring gutter, etc. is collected by the hood 2,
The dust is sucked in by a large exhaust fan 4 installed on the ground through a dust collection duct 3 connected to a hood 2, and the dust is collected by a bag filter 5.

On the other hand, abnormal dust gases etc. from the taphole are sucked from a hood 6 on the ceiling of the building through a dust collection duct 7 by a large exhaust fan 8 installed on the ground, and collected by a bag filter 9. However, this method has the following three serious drawbacks.

○A Pressure loss of dust collection hood and duct is 300m/m
Aq, and the pressure loss of the bag filter is about 250m/mAq, making the exhaust fan very large and requiring huge operating costs.

○B Abnormal dust from the taphole rises to the ceiling of the building due to the rising heat, and this dust is sucked through the hood in the ceiling by an exhaust fan installed on the ground, and collected by a bag filter. Although it is dusty, in this case forced suction is used, which sucks in even the excess air inside the cast bed. As a result, the exhaust fan becomes large, resulting in unnecessary operating costs.

○C During normal tapping, the taphole is opened and closed using a Matsudogun opening machine, so it is necessary to remove part of the large gutter cover in front of the taphole, and during this time complete dustproof measures cannot be taken. In this case, the dust gas cannot be handled by the primary dust collection equipment, so it is necessary to collect the dust using the same system as in A above.

Due to the above-mentioned drawbacks, this system has an enormous operating cost, which poses a problem in terms of energy conservation. As a way to reduce operating costs, power-saving systems such as controlling the rotation speed of exhaust fans have been adopted, but operating costs are still considerable. Furthermore, as a measure to reduce operating costs, there is a method of replacing the bag filter for secondary dust collection with an electrostatic precipitator. This is a device in which an electrostatic precipitator is mounted on the upper part of the casting house, and is called a so-called electrostatic precipitator mounted directly on the building, and has already been proposed in Japanese Patent Publication No. 4123/1983.

FIG. 2 shows a system in which the primary dust collection equipment is the same as the conventional one, but the secondary dust collection equipment has been improved to the one described above. This system collects abnormal dust gas from the tap hole 1 using an electric precipitator 10 mounted on the ceiling of the building. In this case, a so-called natural ventilation method is adopted in which the dust gas is generated by thermal upward currents, so a large exhaust fan is not required, resulting in a significant reduction in operating costs for the secondary dust collection system. However, the electrostatic precipitator is only used when there is abnormal dust generation or when the taphole is opened and closed, and otherwise it is in a so-called idle state.Although the utilization rate is very low, the electrostatic precipitator is always charged. . On the other hand, the primary dust collection facilities 2 to 5 are the same as before and have not been improved, resulting in enormous operating costs.

Therefore, the present invention provides a system that uses a building-mounted electrostatic precipitator to collect both local dust gas and abnormal dust gas during normal tapping, thereby significantly reducing power costs. .

The present invention has a plurality of electrostatic precipitators mounted on the ceiling of the building, and while it is possible to collect abnormal dust gas etc. from the taphole as in the past, this abnormal dust generation is rare (a few cases). Therefore, we focused on the fact that most of the electrostatic precipitators are idle and the efficiency of the equipment is extremely poor. This electric dust collector is intended to collect locally generated dust gas from gutters, hot metal slag pits, etc. The reason why this method is possible is that while abnormal dust generation occurs at the beginning or end of the tapping process, lap tapping is carried out in such a way that abnormal dust generation does not occur at the same time. That is, since one of the dust collectors is idle, even if abnormal dust generation occurs, dust collection is possible by diverting the locally generated dust gas generated at the same time to the other electrostatic precipitator. In addition, since the local dust generation air volume during normal tapping and the abnormal dust generation air volume are about the same,
It is possible to process both dust gases without significantly increasing the capacity of conventional building electric precipitators.

However, according to the present invention, the locally generated dust gas from the lever is sucked in by a small exhaust fan, then guided through a dust collection duct to the bottom of the electric dust collector installed on the ceiling of the building, and then evenly dispersed by a nozzle installed at the end of the duct. The dust is collected using an electric precipitator using the natural draft of smoke. In this case, for example, if abnormal dust generation occurs at the final stage, the abnormal dust generation gas will be treated with the electrostatic precipitator directly above the tap hole, and the local dust generation gas in the same system will be collected by the other idle electrostatic precipitator. to be processed.

This makes it possible to treat local dust gas and abnormal dust gas during normal tapping with the building electric precipitator. In this case, locally generated dust gas requires an exhaust fan, but since there is no need for a bag filter and the length of the dust collection duct is about half that of the conventional one, the pressure loss is 100%.
~50m/mAq, which means that a small exhaust fan is sufficient. Furthermore, since the electricity cost of the electrostatic precipitator is small, it is possible to significantly reduce the electricity cost compared to conventional systems, which greatly contributes to energy conservation. The equipment cost is also half that of the conventional type and improved type. Furthermore, since there is no need to install an exhaust fan or bag filter above ground, the site around the blast furnace can be used more effectively.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In FIGS. 3 and 4, 11 is a blast furnace.
This blast furnace has two tap ports 12a and 12b. 13 is a hood (or cover) for local dust collection
The dust that is generated during normal tapping is collected from the taphole, large culvert, skimmer, hot metal slag trough, hot metal pouring trough, etc. 14a and 14b are each of these hoods 13
This duct 14a, 1
The rear end of 4b is a small exhaust fan 15 installed on the cast bed.
Connect to. Dust collection ducts 16a and 16b are further connected to this exhaust fan 15, and the other end is located below electric dust collectors 18a and 18b mounted on the building 17. Two electric precipitators 18a and 18b are provided corresponding to the number of tap holes 12a and 12b.
It is desirable to install each directly above the tap hole. A plurality of dust collecting gas distribution nozzles 19 are provided in the horizontal parts of the dust collecting ducts 16a, 16b located below the electric dust collectors 18a, 18b, facing the electric dust collectors 18a, 18b. In Fig. 5, 20 is the nozzle 19
A shielding plate provided above, 21 a chute disposed on both sides of the nozzle 19, and 22 a drainage gutter. The dust cleaning water that is intermittently injected from the upper part of the electrostatic precipitators 18a and 18b flows out from the drain gutter 22 without entering the nozzle 19. In FIG. 3, 23 is a connecting duct that connects the dust collecting ducts 16a and 16b, 24 is inside the connecting duct 23, and 25, 26 are inside the dust collecting ducts 16a and 16b on both sides of the connecting duct 23, respectively. and switching dampers 27 and 28 are provided. When the dust is abnormally generated, the dust gas rises up to the ceiling of the building due to the rising heat and rises as shown at 29 in FIG.
Dust is collected by b. On the other hand, dust gas generated during normal tapping is collected by each hood 13, dust collection ducts 14a, 14b, and exhaust fan 1.
5 and the dust collecting ducts 16a, 16b to the bottom of the electrostatic precipitators 18a, 18b, and as shown at 30 in FIG. Dust is collected by 18b. In FIG. 4, numeral 31 indicates a ventilation gear rally for reinforcing ventilation within the building. In order to make the present invention more effective, it is possible to provide a bellows, water or sand seal at the connection between the blast furnace main body and the building to ensure airtightness, or to prevent cross winds from entering the casthouse from outside. Therefore, it is an effective means to provide a screen between the vertical part of the casthouse building and the casthouse surface.

The configuration of one embodiment of the present invention is as described above,
First, to explain the dust collection operation during individual tapping using the two tapholes 12a and 12b, the abnormal dust generation at the start of tapping from the taphole 12a and the local dust generation during the subsequent normal tapping are as follows. Dust is collected by an electric precipitator 18a located directly above the tap hole 12a. When tapping from the tap hole 12a reaches the final stage and abnormal dust generation and local dust generation occur at the same time, the abnormal dust generation is collected by the electrostatic precipitator 18a located directly above the tap hole 12a, but the local dust generation is Collect dust using an electric precipitator No. 18b. That is, by closing the switching dampers 25 and 28 in FIG. 3 and opening the intermediate damper 24, the dust collecting gas flows through the connecting duct 23 from right to left and is collected by the electrostatic precipitator 18b.
Once the tapping from the taphole 12a is completed, the taphole is then tapped from the taphole 12b, but the operation is exactly the same as in the above case.

Next, to explain the dust collection work during lap tapping work, abnormal dust generation at the start of tapping from the tap hole 12a, local dust generation after that, and abnormal dust generation at the end of the tap hole 1
Dust is collected by an electric precipitator 18a directly above 2a, and in the final stage of local dust generation, the switching dampers 25 and 28 are closed, the intermediate damper 24 is opened, and the dust is collected by an electric precipitator 18b. When tapping from the taphole 12b starts after tapping from the taphole 12a, abnormal dust generation at the start of tapping, local dust generation after that, and abnormal dust generation at the end are caused by the taphole. Electrostatic precipitator 18b directly above 12b
The terminal stage localized dust generation that occurs simultaneously with the terminal stage abnormal dust generation is collected by the electrostatic precipitator 18a by closing the switching dampers 27 and 26 and opening the intermediate damper 24. In this case, both the localized dust generation from the taphole 12a at the final stage and the localized dust generation after the start of tapping from the taphole 12b are lap-collected at the same time by the electrostatic precipitator 18b, but the electrostatic precipitator The capacity is designed based on the larger air volume by comparing this lap dust collection and abnormal dust collection.

The above embodiment shows an example in which two electrostatic precipitators are used in the case of two tapholes, but this can also be applied when the number of tapholes and electrostatic precipitators is increased, as shown in Figs. 6 and 7, for example. The invention can be put into practice. In this example, the radix of the electrostatic precipitator corresponds to the number of tapholes;
It is possible to reduce the number of electrostatic precipitators by changing the layout of large gutters, tilting gutters, etc., and by installing hanging curtains and partition walls above the building.

As described in detail above, the present invention is designed to collect all the dust gas generated during normal tapping, which is the primary dust collection system, and the abnormal dust gas from the taphole, which is the secondary dust collection system, by using an electric appliance directly mounted on the building. Since dust is collected using a dust collector, operating costs can be significantly reduced compared to conventional and improved dust collection systems, which greatly contributes to energy conservation.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams of the conventional method, and Figures 3~
Fig. 7 shows an embodiment of the present invention, Fig. 3 is an overall explanatory view, Fig. 4 is a side view of Fig. 3, and Fig. 5 is a dust gas distribution nozzle section provided in the horizontal part of the dust collection duct. 6 and 7 are plan views of the other layouts shown in FIGS. 3 and 4. 11...Blast furnace, 12a, 12b, 12c, 12d
...Tackle mouth, 13...Hood or cover, 14a, 1
4b, 16a, 16b...dust collection duct, 15...exhaust fan, 17...building, 18a, 18b, 18c, 18
d...Electrostatic precipitator, 19...Distribution nozzle, 23...Connection duct, 24-28...Switching damper.

Claims (1)

[Claims] 1 Multiple electrostatic precipitators are installed on the blast furnace building, and a dust collection hood or cover is installed at the point where dust is generated during normal tapping for each of the multiple tap holes, and this hood or cover and the above electrostatic precipitator are installed. A dust collection duct is connected to the lower part of the electrostatic precipitator via an exhaust fan, and a dust collection duct located at the lower part of the electrostatic precipitator is provided with a distribution nozzle for the combined dust gas, and each dust collection duct is connected to a connecting duct with a switching valve. Blast furnace casthouse dust collection equipment characterized by being connected by.