JPH0256588B2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) This invention provides two arc furnaces that are installed together and operated by alternately switching between preheating and melting, thereby improving the melting efficiency of the arc furnace and saving power by preheating. Concerning preheating equipment for an arc furnace with a furnace attached.

The present invention also relates to raw material preheating equipment for preheating raw metal scrap fed into the arc furnace using fuel, thereby saving power during the electric furnace melting stage.

(Prior Art) A conventional example of an arc furnace in which two arc furnaces are installed together and melting and preheating are alternately repeated is shown in FIG. 9. In this case, the preheating furnace lid is of a rotating type to prevent interference with the rotation of the electrodes, and a large installation space is required to prevent interference with the preheating furnace lid, and the rotation time of the preheating furnace lid is limited. It has the disadvantage of being long, which makes it undesirable in terms of equipment configuration.

As shown in FIG. 9, a furnace body 1a and a furnace body 1b are installed side by side, and an electrode 2 is set on 1a.
It is being dissolved. On the other hand, a preheating device 3 is installed in the furnace 1b.

Next, when switching the preheating furnace to 1a and the melting furnace to 1b, the melting furnace lid 4 moves to the position shown by the two-dot chain line A around the turning king pin 5. In that case, the pivot post 6 of the preheating device 3 has a radius r indicated by a chain double-dashed line.
It cannot be installed within the range due to interference. For example, in the case of a 20t furnace, the radius r of A is about 8m. If the swing post 6 is installed outside this range, the occupied distances L and W of the preheating device 3 will be 17, respectively.
16 meters, requiring an extremely large amount of space. In addition, the angle required to switch the preheating device 3 is approximately 270°, which takes a long time, and there is a disadvantage that the operator cannot enter that area during switching due to the danger of heat radiation from the preheating device 3 and falling objects. Was.

Next, when performing preheating, conventionally, in order to save power during the electric furnace melting stage, a vertical hole is made in the scrap, which is the raw material fed into the arc furnace, and a combustion chamber is placed above the hole. It has been practiced to preheat raw materials by burning fuel in a combustion chamber (for example, Japanese Utility Model Application No. 59-142698). The inventors have already
In Japanese Patent Application No. 132,895/1984 filed on June 29, 1984, the company proposes a control method for recycling exhaust gas in order to reduce the amount of preheating fuel and reduce loss due to oxidation of raw materials.

In this raw material preheating method, it is necessary to complete combustion in a small volume of combustion space, and to pass gas into the scrap layer, combustion with a high discharge pressure to overcome the pressure loss is required. It is important that the pressure drop in the exhaust gas system is small.

In the conventional technology described above, there is a problem in that combustion becomes unstable because circulating exhaust gas with a low oxygen content is directly mixed with the combustion flame, and soot is generated as unburned material. The generation of soot results in soot adhering to scraps, hoods, ducts, and dampers.
This causes problems such as deteriorating the working environment and requiring periodic soot removal.

In addition, in order to prevent the circulating exhaust gas from immediately mixing with the combustion flame, the circulating exhaust gas must be ejected at high speed, resulting in a problem of increased pressure loss in the circulating exhaust gas system. Therefore, the head of the circulating exhaust gas blower becomes high, resulting in the disadvantage that the advantage of preheating is reduced by the power consumption of the blower.

(Problems to be Solved by the Invention) The present invention aims to reduce the vast occupied space required by the conventional preheating equipment for a dual-furnace arc furnace, and to provide extremely rational equipment with short travel time. This is the purpose. Moreover, the present invention
The purpose of this is to provide a raw material preheating equipment that effectively eliminates the above-mentioned drawbacks of the conventional raw material preheating equipment used in the preheating equipment of an arc furnace. There is no adverse effect due to generation, there is little pressure loss in the circulating exhaust gas system, and further energy savings are possible.

(Means for Solving the Problems) The gist of the present invention is to provide a traversing carriage that moves in a direction perpendicular to the running carriage on top of the running carriage that runs parallel to a straight line connecting the centers of the two furnaces of a dual-furnace arc furnace. A trolley is provided, and the transverse trolley can be moved horizontally on the running trolley to a position above the furnace in a cantilevered state, and the material preheating combustor and dust collection hood are installed on the transverse trolley so that they can be raised and lowered independently. This is a preheating equipment for a two-furnace arc furnace.

(Operation, Example) Next, the operation of the present invention will be explained based on an example shown in the drawings.

What is shown in FIGS. 1 and 2 is an embodiment of the present invention, in which a furnace body 1a and a furnace body 1b are installed side by side, and an electrode 2 is set in the furnace body 1a, which is in the process of melting. On the other hand, a preheating device 9 is set in the furnace body 1b.

A rail 10 is laid parallel to a straight line connecting the centers of the furnace bodies 1a and 1b, and the rail 10
A traveling carriage 11 is provided which runs parallel to the straight line above. A traverse guide 12 having an I-shaped or [-shaped cross-section, etc.) with upper and lower running flanges is provided on the upper part of the traveling cart 11, and a traversing wheel 13 is sandwiched between the upper and lower running flanges of the traversing guide 12. It looks like it's running. Furthermore, the transverse wheel 1
A transverse carriage 14 is mounted on the upper part of the furnace body 1b when moving forward.
4a is configured to overhang and protrude.

A preheating combustor 15 is attached to the front part 14a of the traversing truck so that it can be raised and lowered via a preheating combustor lifting device 16 consisting of a cylinder, a rod, a pulley, and a chain, and a preheating gas is blown into the furnace body 1b. It's getting crowded. A dust collecting hood 17 is attached to the front portion 14a of the traversing truck so as to surround the outer periphery of the preheating combustor 15 so as to be movable up and down via a dust collecting hood elevating device 18 composed of a cylinder and a rod.

A dust collection duct 19 is provided in a part of the dust collection hood 17, and is configured to communicate with a dust collection pipe 20 to collect dust.

With this equipment, for example, melting in the furnace body 1a,
To explain the procedure for switching from the preheating state to the opposite in step b, the preheating combustor 15 and the dust collection hood 17 set in the furnace body 1b are raised separately, the traversing cart 14 is moved back on top of the traveling cart 11, and the steps are as follows. A step of moving the traveling cart 11 toward the furnace body 1 from the opposite part of the furnace body 1b.
a step in which the electrode 2 and the melting furnace wall 4 move up from the furnace body 1a (not explained in detail); a step in which the electrode 2 and the melting furnace wall 4 rotate from the furnace body 1a to the furnace body 1b; A step in which the electrode 2 and the melting furnace wall 4 are lowered relative to the furnace body 1b, a step in which the traversing truck 14 advances on the traveling truck 11 and moves to the upper part of the furnace body 1a, a step in which the preheating combustor 15 and the dust collection hood 17 are It is possible to switch between preheating and melting through the steps of lowering separately and setting in the furnace body 1a.

In this case, the range occupied by these operations is, for example, in the case of a 20t arc furnace, L is approximately 12m and W is approximately
This allows it to move within a much narrower range of 12 meters.

According to the present invention, it is possible to significantly reduce the size of the building attached to the equipment, which is extremely economical, and because the moving distance is short, the switching time is short and efficient, and the furnace body 1a or the furnace body The time that the furnace mouth of 1b is left open is shortened, contributing to the reduction of heat loss. Furthermore, the dangerous range for work is narrowed, and an extremely favorable layout can be provided from the standpoint of work safety.

If a device according to an embodiment of the present invention shown in FIG. 3 is used as the preheating combustor 15, the raw material can be preheated more effectively.

As shown in FIG. 3, in this device, a vertical opening 21 is provided in the raw material 29 introduced into the arc furnace 1b that performs preheating operation, and a combustion chamber 22 is placed above the opening to preheat the raw material. The exhaust gas after preheating is recycled and used. In this raw material preheating device, the combustion chamber 22
A fuel combustion chamber 23 for burning fuel is provided in the center of the fuel combustion chamber 23, and an annular circulating exhaust gas flow path 24 for introducing circulating exhaust gas is provided around the outer periphery of the fuel combustion chamber 23. Fuel combustion chamber 23
Fuel is supplied from the fuel supply nozzle 25, and combustion is performed using air supplied from the combustion air flow path 26.
Since circulating exhaust gas is not mixed here, fuels such as kerosene, heavy oil, LPG, and coke are stably burned, and then mixed in the mixing chamber 27, so that no soot is generated due to unburned combustion.

Since the circulating exhaust gas is introduced into the mixing chamber 27 through the annular circulating exhaust gas passage 24, there is no need to provide a blow-off nozzle or the like to avoid early mixing with the combustion flame as in the conventional case. Reducing the required pressure, circulating exhaust gas blower 28
(installed on the building side) can reduce the lift height.

The tip of the mixing chamber 27 is tapered, resulting in a high-speed blowout flow rate of 30 m/s to 100 m/s.

In such a preheating method, the wall of the fuel combustion chamber 23 is heated, so it is necessary to cool this wall to maintain its strength, but the temperature of the circulating exhaust gas is relatively low at about 0 to 500°C. Therefore, it becomes possible to perform airflow cooling, and it is also possible to avoid structural difficulties. Further cooling may be enhanced by water cooling this wall.

As described above, according to the raw material preheating equipment according to the present invention, combustion stability is good, there is no adverse effect of soot generation, capacity reduction and power saving of the circulating exhaust gas blower can be achieved, and preheating is achieved by constant combustion gas temperature. The effects of stabilization and reduction of scrap oxidation loss are extremely large.

Raw material preheating combustor 1 used in the preheating equipment of the present invention
5 and dust collection hood 17 each lifting device 1
Other examples of devices of No. 6 and 18 are shown in FIGS. 4a and 4b. 4a and 4b show one embodiment of the present invention, and FIG. 4a shows a state in which the raw material preheating combustor 15 and the dust collection hood 17 are raised above the arc furnace 1b. The raw material preheating combustor 15 has supporting parts 3 fixed on both sides thereof.
0 via a pulley 31.
A support part 3 is attached to one of the sides of the raw material preheating combustor 15.
0 is fixed at 2 or more, or the raw material preheating combustor 1
5 may be fixed. Pulley 31 is connected to cylinder 32 and rod 33
is supported on 14a by. 34 is a belt or chain, and 14a is the front part of the traversing truck. The dust collection hood 17 is suspended from the support portion 30 by a hanging rod 35. The hanging rod 35 freely passes through a hole provided in the support section 30 and has a locking section 36 at its upper end.

FIG. 4b shows the lowered state, in which the raw material preheating device 15 is mounted above the opening 21 of the raw material 29, and the dust collection hood 17 is placed on the upper part of the arc furnace 1b.

To change the state from FIG. 4a to FIG. 4b, proceed as follows. In Figure 4a, cylinder 3
The second rod 33 is lowered to lower the support part 30, and the raw material preheating device 15 and the dust collection hood 17 suspended from the support part 30 are lowered, respectively. Once the dust collection hood 17 is placed on the arc furnace 1b, the hanging rod 35 is moved down as the support section 30 descends.
The locking part 36 moves upward away from the support part 30, and only the raw material preheating device 15 continues to descend and the raw material 2
It is placed on top of the hole 9 and stopped.

In order to change the state from Fig. 4b to Fig. 4a,
The support part 30 is raised to raise the raw material preheating combustor 15. When the support portion 30 reaches the locking portion 36 of the hanging rod 35, the locking portion 36 and the hanging rod 35 rise, and thereby the dust collection hood 17 rises together with the raw material preheating combustor 15. The movement of the cylinder 32 is stopped at the position shown in FIG. 4a, and the support part 30 is stopped.

Next, some modified examples of the device shown in FIG. 2 are shown in FIGS.
c, shown in Fig. 6a, b.

5a to 5c show the state in which the traversing cart 14 advances from the traveling cart 11 to the arc furnace 1b and is undergoing preheating operation in the arc furnace 1b; FIG. 5a is a plan view, and FIG. 5b is a top view. FIG. 5c is a right side view. However, the pipes 42 and 43 show a state in which the raw material preheating combustion device 15 is in the middle of being raised.

In this embodiment, a combustion air pipe 42 is connected to the traversing truck 14 at one end to the raw material preheating combustor 15.
A pipe group A is provided which includes a circulating exhaust gas pipe 43 and an exhaust gas pipe 44 connected at one end to the dust collection hood 17. Further, the traveling truck 11 is provided with a pipe group B consisting of a combustion air pipe 42', a circulating exhaust gas pipe 43', and an exhaust gas pipe 44'. One end of each pipe of the pipe group B is removably connected to the other end of each pipe of the pipe group A by break flanges A, B, and C, and the circulating exhaust gas pipes 43' and The other end of the exhaust gas pipe 44' is removably connected to one end of fixed pipes 45 and 46 provided on the building side, respectively, by break flanges B and E, respectively.

On the other hand, fuel is supplied to the fuel supply pipe 4 installed on the building side.
1' is supplied to the raw material preheating combustor 15 via a fuel hose 41. Further, the traveling truck 11 is provided with a combustion air fan 47 connected to the other end of the fuel air pipe 42' of the pipe group B.

As shown in FIGS. 5a to 5c, fuel is supplied to the raw material preheating combustor 15 through a fuel hose 41 from a fuel supply pipe 41' installed in a building, for example. Fuel air is supplied from a combustion air fan 47 provided on the traveling truck 11 to combustion air pipes 42',
42, and the circulating exhaust gas is supplied from the building side to the raw material preheating combustor 15 by a circulating exhaust gas blower (not shown) through circulating exhaust gas pipes 43' and 43, respectively. Exhaust gas is collected by dust collection hood 17
The gas is then discharged to the building side through the exhaust gas pipes 44, 44'. In FIGS. 5a and 5b, reference numeral 48 is a swivel joint, which allows the piping 42,
43 can move up and down together with the raw material preheating combustor 15.
6a and 6b show a state in which the traversing truck 14 is retracted onto the traveling truck 11 and is moving on the traveling truck,
FIG. 6a is a plan view, and FIG. 6b is a front view. As shown in Figure 6 a and b, the break flange A~
In case E, all the pipes are disconnected.

FIGS. 7a and 7b are partially enlarged sectional views of the break flange C shown in FIGS. 5a and 5b. FIGS. 7a and 7b correspond to the break flange D shown in FIG. 5a, and when FIGS. 7a and b are laid down, their horizontal views correspond to the break flanges A, B, and E. FIG. 7a shows a state in which the combustion air pipes 42, 42' are disconnected. A connecting tube 60 that can be expanded and contracted or bent is contracted or bent by the cylinder 50. Reference numeral 60' indicates the cross-sectional shape. The contact member 62 provided on the support frame 61 is spaced apart from the pipe 42'.

FIG. 7b shows the state in which the pipes 42, 42' are connected. The connecting pipe 60 is extended by the rod 51 of the cylinder 50 and is connected to the fitting member 62.
is in close contact with the pipe 42'. Reference numeral 60' indicates the cross-sectional shape. To release the connection, the rod 51 of the cylinder 50 is retracted as shown in FIG. 7a.

As shown in FIGS. 5a and 5b, a heat-resistant case 80 is installed on the traveling trolley 11. This is arranged so that it is located below the high-temperature raw material preheating combustor 15 when the traversing truck 14 moves backward toward the traveling truck 11 and retreats. The raw material preheating combustor is then lowered by the lifting device 16 and housed in a heat-resistant case to protect surrounding equipment from high temperatures. When the traversing truck 14 travels on the traveling truck 11, the raw material preheating combustor is raised by the lifting device 16 and taken out from the heat-resistant case.

In addition, as shown in FIG.
2, the wheels are rotated by a motor via a drive shaft and run on the rail 10.
Further, as shown in FIG. 5a and FIG. 8, the traversing truck 14 is equipped with a motor 100 and a traversing drive shaft 101, and the wheels 13 are rotated by the motor 100 via the drive shaft 101 to guide the traversing. 12, the traversing truck 14 runs on the traveling truck 11.

(Effects of the Invention) As explained above in detail, according to the present invention, it is possible to significantly reduce the size of the building attached to the equipment, which is extremely economical, and the changeover time is short because the moving distance is short. It is short and efficient, and the time the furnace mouth of the furnace body is left open is shortened, contributing to the reduction of heat loss. Furthermore, the dangerous range for work is narrowed, and an extremely favorable layout can be provided from the standpoint of work safety.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams showing an embodiment of preheating equipment for a dual-furnace arc furnace according to the present invention, FIG. 1 is a plan view, and FIG. 2 is a partially sectional side view,
Fig. 3 is a sectional view showing an embodiment of the preheating combustor used in the preheating equipment of the present invention, and Figs. FIGS. 5 a to 6 c and 6 a and b are partially cross-sectional explanatory views showing one embodiment of the lifting device, and FIG. 5 a is a plan view, and FIG. Figure b is a partially sectional front view, Figure 5 c is a right side view, and the pipes 42 and 43 show the raw material preheating combustor 15 being raised halfway, and Figure 6 a is a partial cross-sectional front view.
is a plan view, FIG. 6b is a front view of FIG. 6a, FIGS. The figure is an omitted vertical cross-sectional view taken in the direction of the - arrow in FIG. 1a, 1b...furnace body, 2...electrode, 3...preheating device, 4...melting furnace lid, 5...swivel king pin,
6... Rotating post, 9... Preheating device, 10... Rail, 11... Traveling trolley, 12... Traversing guide,
13... Traversing wheel, 14... Traversing trolley, 14a...
...Front part of the traversing truck, 15... Preheating combustor, 16...
Preheating combustor lifting device, 17...dust collection hood, 18
...Dust collection hood lifting device, 19...Dust collection duct,
20... Dust collection pipe, 21... Opening, 22... Combustion chamber, 23... Fuel combustion chamber, 24... Annular circulating exhaust gas passage, 25... Fuel supply nozzle, 26... Combustion air flow Channel, 27... Mixing chamber, 28... Circulating exhaust gas blower, 29... Raw material, 30... Support part,
31... Pulley, 32... Cylinder, 33... Rod, 34... Belt or chain, 35... Hanging rod, 36... Locking part, 41... Fuel hose, 4
1'... Fuel supply pipe, 42, 42'... Combustion air pipe, 43, 43'... Circulating exhaust gas pipe, 44, 4
4'...Exhaust gas piping, 45, 46...Fixed piping,
47... Combustion air fan, 48... Swivel joint, 50... Cylinder, 51... Rod,
60... Connecting pipe, 61... Support frame, 62... Close contact member, 80... Heat resistant case, 90... Motor, 91... Speed reduction device, 92... Drive shaft, 100
...Motor, 101...Transverse drive shaft.

Claims (1)

[Claims] 1 A traversing truck that moves in a direction perpendicular to the traveling truck is installed on top of the traveling truck that runs parallel to the straight line connecting the centers of the two furnaces in a two-furnace arc furnace. Preheating equipment for an arc furnace with two furnaces, which is movable to a position above the furnace in a holding state, and is characterized in that a material preheating combustor and a dust collection hood are installed on a transverse carriage so that they can be raised and lowered independently.