JPH0316599B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention separately encloses an arc furnace and a preheating tank,
This invention relates to arc furnace equipment having a small and highly airtight enclosure in which raw materials are charged into the arc furnace within the enclosure.

Conventionally, an arc furnace and a preheating tank for preheating raw materials are surrounded by a single enclosure, and a part of the enclosure is opened and a charging bucket is placed into the enclosure using a crane or the like and placed in the preheating tank. Raw materials were being input.

Therefore, it had the following drawbacks.

(i) The structure of the enclosure becomes complicated because the enclosure is provided with a cutout.

(ii) Since the enclosure is opened to operate the crane, the enclosure is not tightly sealed and smoke leaks.

(iii) Since the charging bucket passes through the opening of the enclosure, there is a risk of damage to the enclosure or the arc furnace due to incorrect operation of the crane.

The present invention solves all of these drawbacks, and further improves the operating rate, increases the energy utilization rate, reduces the power consumption rate, and simplifies the equipment to reduce equipment costs. This is related to furnace equipment.

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

FIGS. 1 to 4 show an embodiment of the present invention,
Arc furnace main body 2 and ladle 3 installed on tilting floor 1
A pair of rails 4 are constructed so as to be perpendicular to the line connecting the arc furnace body 2 and sandwich the arc furnace main body 2. A pair of rails 5 are positioned on an extension line of the rail 4.
is installed on a work floor 6, and a trolley 8 carrying a raw material preheating tank 7 is disposed on the rails 5 so as to be movable up to above the arc furnace main body 2.

The arc furnace main body 2 and ladle 3 are surrounded by an arc furnace-side enclosure 9, and the preheating tank 7, trolley 8, and rail 5 are surrounded by a preheating tank-side enclosure 10, and the ceiling of the preheating tank-side enclosure 10 is surrounded by the trolley 8. A movable ceiling 13 is constructed so that it can be moved by wheels 12 on a rail 11 constructed in a direction perpendicular to the running direction of the preheating tank 7, and a top cover 14 for sealing the upper part of the preheating tank 7 is attached to the movable ceiling 13 using a hydraulic cylinder or the like. When the movable ceiling 13 is moved, the top cover 14 is also moved to a standby position 15, and the preheating tank 7 is opened so that raw materials can be charged from above using a charging bucket 16. .

A seal cover 17 that opens in half is provided at the bottom of the preheating tank 7 so that it can be sealed tightly, and is supported by a load holder 19 that is raised and lowered by a hydraulic cylinder 18 from the bottom of the seal cover 17. This prevents the seal cover 17 from being deformed and unable to open or close due to strong impact when raw materials are introduced.

A direct-drawing elbow 2 is attached to the furnace cover 20 of the arc furnace main body 2.
1 is provided so that high-temperature exhaust gas generated from the arc furnace main body 2 can be introduced into the top cover 14 and the raw material preheating tank 7 through the exhaust gas introduction ducts 22 and 23, and the exhaust gas that has passed through the raw material is introduced into the seal cover 17. The exhaust gas is returned to the arc furnace main body 2 via an exhaust gas return duct 24 which is detachably provided to the exhaust gas return duct 24 and an exhaust fan 25 which is provided in the middle of the exhaust gas return duct 24. The exhaust gas introduction duct 22
A damper 26 is provided in the middle of the exhaust gas return duct 24, and a butterfly valve 27 is provided in the middle of the exhaust gas return duct 24 to adjust the flow rate of the exhaust gas.

The arc furnace side enclosure 9 and the preheating tank side enclosure 10
The partition wall 28 between the preheating tank 7 and the trolley 8 is separated to a size that allows the preheating tank 7 and the trolley 8 to pass through, and is fixed to the trolley 8. It is designed so that it can be moved up to The direct pull elbow 21 and the exhaust gas introduction duct 22
At the connection part, there is a sliding pipe 2 on the exhaust gas introduction duct 22 side.
9 is provided to facilitate gap adjustment after the arc furnace is tilted during tapping and slag removal or after the furnace lid 20 is rotated during raw material charging.
A flange 30 is provided at each connecting portion to facilitate joining.

In the figure, 31 is the bottom plate of the charging bucket 16, 32 is an exhaust gas duct connected to the arc furnace side enclosure, and 33 is a butterfly valve provided in the exhaust gas duct 32.

Next, to explain the operation of the present invention, when introducing raw materials into the preheating tank 7, the exhaust gas introduction duct 22
After closing the damper 26 and the butterfly valve 27 of the exhaust gas return duct 24 to prevent exhaust gas from flowing out of the arc furnace, the top cover 14 attached to the movable ceiling 13 is raised and separated from the preheating tank 7, and the movable ceiling 13 to the rail 1 in the tapping direction of the arc furnace.
1 Slide the top. The top cover 14 moves to the standby position 15, and the upper part of the preheating tank 7 is opened. A charging bucket 16 for transporting raw materials is connected to a preheating tank 7.
The raw material is put into the preheating tank 7 while the bucket bottom plate 31 is opened by crane auxiliary hoisting. At this time, the load pedestal 19 is raised in advance by the hydraulic cylinder 18 to support the seal cover 17, thereby supporting the strong impact when the raw material falls and preventing the impact from being transmitted to the cart 8.

After the input of raw materials is completed, the movable ceiling 13 is returned to its original position, the enclosures 9 and 10 are completely sealed, and the top cover 14 is lowered to open the preheating tank 7.
and seal the upper part of the exhaust gas introduction duct 2.
Connect 2 and 23.

The exhaust gas energy generated during melting of raw materials in the arc furnace main body 2 is enormous, especially from the final stage of melting to the refining stage.
2, 23, further passes through the inside of the raw material from above the top cover 14, and reaches below the preheating tank 7,
The exhaust gas is returned from the seal cover 17 to the arc furnace main body 2 via the exhaust gas return duct 24 by the exhaust fan 25.
At this time, the damper 26 and the butterfly valve 27 are opened, but if the exhaust gas returned from the preheating tank 7 to the arc furnace main body 2 is continuously supplied, the amount of exhaust gas in the arc furnace side enclosure 9 will be reduced to the exhaust gas duct 32. Since the ventilation capacity may be exceeded, the damper 26 is used to constantly adjust the flow rate. In this way, since the exhaust gas after preheating is forcibly returned to the arc furnace main body 2 through the exhaust gas return duct 24 by the exhaust gas fan 32, there are times when a large amount of white smoke with foul odor is generated from the arc furnace. The exhaust gas is re-burned at high temperatures in an arc furnace, improving the exhaust gas heat recovery rate and making it possible to significantly reduce electricity consumption.

Next, after the preheating of the raw material is completed, the damper 2
6 and butterfly valve 27, and close the top cover 1.
4 is raised and separated from the preheating tank 7, the connecting portions of the exhaust gas introduction ducts 22 and 23 are also separated. Furthermore,
The cylinder 18 lowers the load holder 19, and the seal cover 17 and the exhaust gas return duct 24
Since the cart 8 becomes movable by disconnecting from the furnace lid 20, the arc furnace main body 2 is opened by swinging the furnace lid 20 forward, and the preheating tank 7, the partition wall 28, and the cart 8 are integrally moved up to just above the opening. It is moved on the rails 5, 4 and stopped directly above the opening by a limit switch (not shown). Next, the seal cover 17 is opened and the preheated raw material is charged into the arc furnace main body 2. Therefore, since the trolley 8 is automatically stopped at a predetermined position, the alignment accuracy is greatly improved compared to the conventional charging method using a crane, there is no melting residue caused by uneven raw materials, and the melting and charging time is reduced. is also significantly shortened.

When the raw material charging is completed, the cart 8 is returned to the original preheating side enclosure 1.
0, the bulkhead 2 fixed to the trolley 8
8 disconnects the arc furnace side enclosure 9 and the preheating side enclosure 10. Furnace lid 2 on arc furnace body 2
While operating the arc furnace with damper 2 installed,
6 and the butterfly valve 27, the raw material can be charged into the preheating tank 7 without emitting exhaust gas outside the enclosures 9, 10, regardless of the operating state of the arc furnace.

In the above operations, the damper 26 and the butterfly valve 27 are closed when charging the raw material into the arc furnace main body 2, when tapping the steel into the ladle 3, when charging the raw material into the preheating tank 7, and when blowing _O2 , and when the butterfly valve 33 is opened, and the generated gas in the arc furnace side enclosure 9 is discharged from the exhaust gas duct 32 to a dust collector bag filter (not shown).

It should be noted that the arc furnace equipment having the enclosure according to the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

As described above, the arc furnace equipment having the enclosure of the present invention exhibits various excellent effects as described below.

() The arc furnace and the raw material preheating tank are surrounded by separate enclosures, and the ceiling of the enclosure on the preheating tank side is movable, and part of the partition walls of both enclosures are movable, so that the outer periphery of the enclosure is There are no notches, increasing rigidity. Therefore, the enclosure can be constructed from members with low strength, and the construction cost can be reduced.

() There are no cutouts on the outer periphery of the enclosure for opening/closing the door or for wires, so it can be completely enclosed and there is no smoke leakage. Therefore, the smoke collection air volume is small, which is economical.

() The ceiling of the enclosure on the side of the preheating tank is made movable so that raw materials can be charged into the preheating tank from outside, so there is no need to use a crane to pass the charging bucket through the opening, which prevents crane misoperation. Collisions caused by this can be prevented, and there is no need to worry about damage to the enclosure.

() The exhaust gas introduction duct that guides high-temperature exhaust gas from the arc furnace to the preheating tank can be opened and closed, making it possible to feed raw materials into the preheating tank regardless of the operating status of the arc furnace, improving crane operating efficiency. can be done.

() The exhaust gas from the arc furnace is used to preheat the raw materials and is then returned to the arc furnace.
High-temperature gas generated in the final melting stage and refining stage of an arc furnace can be effectively used, and the power consumption rate can be significantly reduced.

() The high-temperature exhaust gas from the arc furnace absorbs heat during the preheating of the raw material (as it returns to the arc furnace) and the gas temperature decreases, making it possible to collect dust without gas cooling. Therefore, cooling water is not required. In addition, the temperature of the generated CO gas is low and it does not burn, but is mixed with the gas from inside the enclosure and its concentration is reduced, so it can be safely disposed of and the generation of NO _x is reduced.

() Since the preheated raw material is transferred onto the arc furnace main body together with the preheating tank and bulkhead using a trolley, it is possible to charge the raw material into the arc furnace in a sealed state, preventing smoke leakage. can be prevented.

() Since the preheating tank is moved by a trolley, there is no need for crane operation as in the past, improving stopping accuracy and restorability, preventing unevenness of raw materials, and shortening melting time.

() Similarly, there is no collision with the arc furnace due to erroneous operation of the crane as in the conventional case, and charging can be performed accurately and reliably each time.

() Since the partition wall between the arc furnace side enclosure and the preheating tank side enclosure is fixed by a truck, it opens and closes automatically as the truck moves, so a dedicated drive device is not required.

(XI) When loading raw materials into the preheating tank and charging into the arc furnace, buckets, etc. do not enter the enclosure, so the height of the enclosure can be lowered and construction costs can be reduced. can.

[Brief explanation of the drawing]

FIG. 1 is an overall explanatory diagram of the present invention, FIG. 2 is a detailed explanatory diagram of the arc furnace and raw material preheating tank in FIG. 1, FIG. 3 is a plan view of the present invention, and FIG. 4 is a preheating tank in the present invention. FIG. 3 is an explanatory diagram showing a state in which raw materials are charged into the arc furnace main body. 2 is the arc furnace main body, 4, 5, 11 are rails, 7
is a preheating tank, 8 is a trolley, 9 is an arc furnace side enclosure, 1
0 is a preheating tank side enclosure, 13 is a movable ceiling, 14 is a top cover, 17 is a seal cover, 21 is a direct pull elbow, 22 and 23 are exhaust gas introduction ducts, 24 is an exhaust gas return duct, 26 is a damper, and 28 is a partition wall. shows.

Claims (1)

[Claims] 1. A preheating tank that preheats the raw material using high-temperature exhaust gas from the arc furnace and returns the exhaust gas used for preheating to the arc furnace is mounted on a trolley placed on a pair of rails that sandwich the arc furnace. The arc furnace, the preheating tank, and the cart are each surrounded by adjacent separate enclosures, and a cover for sealing the preheating tank is provided on the ceiling of the preheating tank side enclosure so as to be movable up and down, and the ceiling can be slid. Further, a part of the partition wall of both the enclosures is separated and fixed to the cart so that the enclosure can be moved to the arc furnace side together with the preheating tank so that the raw material can be charged into the arc furnace. Arc furnace equipment with.