JP3755318B2 - Method and equipment for preventing dust accumulation in exhaust gas duct - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and an apparatus for preventing dust accumulation in an exhaust gas duct in a dust collection facility of a refining apparatus that performs powder blowing.
[0002]
[Prior art]
Conventionally, in hot metal pretreatment for hot metal desiliconization, dephosphorization, etc., a refining powder in which lime, fluorite, soda ash, etc. are mixed with iron ore, mill scale, etc. from a dispenser that stores the refining powder is used as a carrier. It is transported together with the gas by a powder transport pipe and added to the molten metal in the refining vessel through the powder lance. For example, the hot metal flowing through the hot metal installed on the blast furnace casting floor is guided to the tilting iron, added to the hot metal in the tilting iron using a lance for powder, and desiliconized, and then received by a topped car. In addition, the powder for refining stored in the dispenser is blown into the hot metal in the topped car or ladle at the hot metal pretreatment plant using the powder lance, and the hot metal pretreatment such as dephosphorization or desulfurization is performed. It is carried out.
[0003]
In a hot metal pretreatment plant that performs hot metal desiliconization, dephosphorization, etc., for example, as shown in FIG. 4, four types of refining powders are stored in four dispensers 6. Of the dispensers 6, No. 1 stores iron oxide A, No. 2 stores quick lime, No. 3 stores iron oxide B, and No. 4 stores soda ash. Each dispenser 6 is supplied with compressed air and maintained at a predetermined pressure. The powder lance 1 is stopped immediately above the topped car 4 by a tiltable lance lifting device 3 provided on the carriage 2.
[0004]
Next, dry air, which is a carrier gas adjusted to a pressure and flow rate suitable for the conveyance of the powder, is opened from the lance 1 for powder by opening the automatic valve 8 so that the powder for refining does not accumulate in the air conduit 7. After blowing out, the powder cutting valve 9 is opened, the powder for refining is poured, and supplied to the air conduit 7. At the same time, the automatic valve 11 disposed in the oxygen conduit 10 is opened to blow out gaseous oxygen adjusted to the required pressure and flow rate from the powder lance 1. Here, excess air is exhausted by an exhaust valve 13 disposed in an exhaust pipe 24 in order to adjust the pressure and flow rate required to blow into the hot metal 12 from the powder lance 1. In many cases, only the carrier gas is blown into the powder lance 1 together with the refining powder without supplying gaseous oxygen via the oxygen conduit 10.
[0005]
Powder for refining (iron oxide A, quicklime, iron oxide B, soda ash) mixed with dry air in the air conduit 7 passes through the flexible hose 14, and gaseous oxygen in the oxygen conduit 10 passes through the flexible hose 15 to powder. While blowing out from the body lance 1, the hot metal 12 is desiliconized by the smelting powder immersed in the hot metal 12 accommodated in the topped car 4 by the lance lifting device 3 and blown from the powder lance 1. A dephosphorization process is performed.
[0006]
In general, when powder is blown, a part of the powder does not meet the original purpose and a part leaks out of the system. For this reason, a dust collection facility with a considerable capacity is installed to collect the leaked powder. Dust-containing gas generated in the furnace during desiliconization and dephosphorization of the hot metal 12 is collected by a dust collection hood 16 that covers the top of the furnace port 5 provided in the topped car 4 and passes through an exhaust gas duct 17. Discharged. The dust-containing gas is cooled by a gas cooler 18 disposed in the middle of the exhaust gas duct 17, and then guided to a dust collector 19 (using an electric dust collector, a bag filter dust collector, etc.) and collected.
[0007]
By the way, when the dust-containing dust is guided to the dust collector 19 via the exhaust gas duct 17 and dust is collected, as shown in FIG. This hinders the air permeability of the dust-containing gas, which causes a decrease in dust collection capability, and there is a problem that the dust 18 accumulated in the exhaust gas duct 17 must be frequently cleaned by removing the manhole 22. When accumulated dust is generated, for example, Japanese Patent Laid-Open No. 9-323050 discloses that gas is supplied from a gas generator to a dust accumulation position of a lower hopper disposed below an electrode provided in an electrostatic precipitator and removed by jetting. A method is disclosed.
[0008]
[Problems to be solved by the invention]
However, in order to inject gas into the dust accumulated in the exhaust gas duct or the lower hopper, a gas generator is required, which increases the equipment cost. In general, in order to prevent environmental pollution due to dust leakage, a dust collector with a considerable capacity is required, which is associated with cost problems. If a dust collector with insufficient capacity is installed with emphasis on the economy, dust accumulates in the dust collection duct, causing problems such as a decrease in dust collection capacity and frequent cleaning of the accumulated dust in the dust collection duct. The point is as described above.
[0009]
An object of the present invention is to solve the above problems and to provide a method and equipment for preventing dust accumulation in an exhaust gas duct without installing a gas generator.
[0010]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention according to claim 1 is characterized in that the powder for refining in the dispenser is fed together with the carrier gas through the powder transport pipe, and from the powder lance to the molten metal in the molten metal container. While being added, the dust-containing gas generated in the molten metal container is collected by a hood disposed above the furnace port of the molten metal container, and dust is collected in the exhaust gas duct when it is collected through the exhaust gas duct to the dust collector. In the accumulation prevention method, exhaust gas from the dispenser is guided through a discharge nozzle to a place where dust in the exhaust gas duct is likely to accumulate through an exhaust pipe, and exhausted. It is a dust accumulation prevention method in the inside.
[0011]
The present invention described in claim 2 is a dispenser for storing a refining powder, a powder transport pipe for transporting the refining powder together with a carrier gas from the dispenser, and a refining powder transported by the powder transport pipe. A powder lance for adding the body to the molten metal in the molten metal container, a hood disposed above the furnace port of the molten metal container for collecting dust-containing gas generated in the molten metal container, and the hood In a refining powder supply facility equipped with a dust collector that collects dust-containing gas via an exhaust gas duct, an exhaust pipe for taking out exhaust gas from the dispenser to a place where dust easily accumulates in the exhaust gas duct A powder supply facility for refining with a dust accumulation preventing device in an exhaust gas duct, characterized in that it extends, faces the exhaust gas duct, and a blow-off nozzle is disposed at the tip of the exhaust pipe.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, four kinds of refining powders are stored in four dispensers 6, and among the four dispensers 6, No. 1 is iron oxide A and No. 2 is quicklime. No. 3 stores iron oxide B and No. 4 stores soda ash. Each dispenser 6 is supplied with compressed air and maintained at a predetermined pressure. The toped car 4 containing a total of four hot metal baths is stopped on the first track and the second track. 4 that are the same as those shown in FIG. 4 are given the same reference numerals, and redundant descriptions are omitted.
[0013]
Powder for refining (iron oxide A, quicklime, iron oxide B, soda ash) mixed with dry air, which is a carrier gas, in the air conduit 7 passes through the flexible hose 14, and the gaseous oxygen in the oxygen conduit 10 is the flexible hose. 15 is blown out from the lance 1 for powder and blown into the hot metal 12 accommodated in the topped car 4 to perform desiliconization and dephosphorization of the hot metal. Excess air is exhausted by the gas exhaust valve 13 of the dispenser 6 while adjusting the pressure and flow rate required to blow into the hot metal 12 from the powder lance 1. In FIG. 1, the cart 2 provided with the tiltable lance lifting device 3 is omitted.
[0014]
Dust-containing gas generated in the topped car 4 during the desiliconization and dephosphorization processes of the hot metal 12 is collected by a dust collection hood 16 that covers the top of the furnace port 5 and is discharged through an exhaust gas duct 17. Here, the exhaust gas duct 17 is divided into two systems by a damper 23 provided in the middle, and the dust-containing gas generated in the two topped cars 4 on the right side in the drawing is disposed in the middle of the exhaust gas duct 17. After being cooled by the gas cooler 18, the dust is introduced into the No. 1 dust collector 19 through the exhaust fan 20, and the dust-containing gas generated in the left two topped cars 4 is led to the No. 1 dust collector 19 and collected. .
[0015]
By the way, when dust-containing dust is collected by being guided to the dust collector 19 via the exhaust gas duct 17, dust is contained in the exhaust gas duct 17 at a portion where the exhaust gas duct 17 is bent from the vertical to the horizontal or a portion partitioned by the damper 23. 21 is easy to deposit. Therefore, in the present invention, the No. 1 blowing nozzle 25 is disposed in the vicinity of the damper 23, and the No. 2 blowing nozzle 25 and the No. 3 blowing nozzle 25 are disposed in the vicinity of the bent portion of the exhaust gas duct 17, Each is exposed to the exhaust gas duct 17. The exhaust pipes 24 taken out from the four dispensers 6 are extended and led to a place where dust is likely to accumulate, and the tip end portions of the exhaust pipes 24 are connected to the respective blowing nozzles 25. FIG. 2 shows a case in which the No. 1 blowing nozzle 25 is arranged in the direction of the exhaust gas flow 26 in the exhaust gas duct 17 in the vicinity of the damper 23, and FIG. The case where the No. 2 blowing nozzle 25 is arranged in the direction of the exhaust gas flow 26 is shown.
[0016]
Next, the operation of the present invention will be described.
Dust-containing gas generated in the topped car 4 during the desiliconization and dephosphorization processes of the hot metal 12 is collected by a dust collection hood 16 that covers the top of the furnace port 5 and is discharged through an exhaust gas duct 17. Excess pressurized air in the dispenser 6 is exhausted to the blowout nozzles 25 (No.1, No.2, No.3) located where the dust in the exhaust gas flowing in the exhaust gas duct 17 is likely to accumulate. The valve 13 is opened and guided through the exhaust pipe 24, and the dust accumulated in the exhaust gas duct 17 is blown away by the gas ejected from the blowing nozzle 25.
[0017]
The surplus air of the dispenser 6 has a pressure to blow away the accumulated dust at the place where it is easy to accumulate, and the amount of air is sufficient. The dust blown off flows on the exhaust gas stream 26, and is guided to the No. 1 dust collector 19 and the other to the No. 2 dust collector through the two exhaust gas ducts 17, and is collected. As a result, dust is prevented from accumulating in the exhaust gas duct 17, and the dust 21 stops only to a small extent in the manhole 22, and the number of cleanings of the accumulated dust can be greatly reduced.
[0018]
【The invention's effect】
As described above, in the present invention, excess pressure exhaust discharged from the dispenser is used, and this is led to a place where the dust in the exhaust gas duct is highly likely to accumulate, and is ejected from the blow nozzle to be accumulated dust in the exhaust gas duct. The dust can be blown away early and collected with a dust collector together with the exhaust gas. For this reason, it is not necessary to add a gas generator to be supplied to the blowout nozzle, preventing a decrease in dust collection capacity caused by accumulated dust in the dust collecting duct, and greatly reducing the work of removing accumulated dust. The effect is enormous.
[Brief description of the drawings]
FIG. 1 is an overall layout view of a refining powder supply apparatus showing only a dispenser according to an embodiment of the present invention on a side surface and the other on a plane.
FIG. 2 is a cross-sectional view showing the direction of arrows AA in FIG.
FIG. 3 is a cross-sectional view showing the direction of arrows BB in FIG. 1;
FIG. 4 is an overall layout view of a refining powder supply apparatus of a conventional example.
FIG. 5 is an explanatory view showing a state where dust is accumulated in an exhaust gas duct according to a conventional example.
[Explanation of symbols]
1 Lance for powder 2 Dolly 3 Lance lifting device 4 Topped car 5 Furnace port 6 Dispenser 7 Air conduit 8 Automatic valve 9 Cutting valve
10 Oxygen conduit
11 Automatic valve
12 Hot metal
13 Exhaust valve
14, 15 Flexible hose
16 Dust collection hood
17 Exhaust duct
18 Gas cooler
19 Dust collector
20 Ventilator
21 dust
22 Manhole
23 Damper
24 Exhaust pipe
25 Outlet nozzle
26 Exhaust gas flow

Claims (2)

The fine powder for refining in the dispenser is pneumatically fed together with a carrier gas through a powder transport pipe, and added from the powder lance to the molten metal in the molten metal container, while the dust-containing gas generated in the molten metal container is When collecting with a hood arranged above the furnace port of the molten metal container and collecting the dust through the exhaust gas duct to the dust collector, the exhaust of the dispenser was formed at the tip of the exhaust pipe via the exhaust pipe. A dust accumulation preventing method in an exhaust gas duct, characterized in that the dust in the exhaust gas duct is ejected from a blowing nozzle to a place where dust in the exhaust gas duct is likely to accumulate. Dispenser for storing refining powder, powder transport pipe for transporting refining powder together with carrier gas from the dispenser, and refining powder transported by the powder transport pipe in the molten metal in the molten metal container A lance for powder to be added, a hood arranged above the furnace port of the molten metal container for collecting the dust-containing gas generated in the molten metal container, and the dust-containing gas collected by the hood through an exhaust gas duct In a refining powder supply facility comprising a dust collector for collecting dust, an exhaust pipe for taking out exhaust gas from the dispenser is extended to a location where dust is likely to accumulate in the exhaust gas duct, A powder supply facility for refining with a dust accumulation preventing device in an exhaust gas duct, characterized in that a blow-off nozzle is arranged at the tip of the exhaust pipe.

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