JPS5952359B2 - Preheating device for charging materials for steelmaking - Google Patents

Description

[Detailed description of the invention] The present invention relates to a preheating device for steelmaking charges.

In the steelmaking process, it is desirable to preheat materials such as scrap, ferroalloy, directly reduced iron, and lime that are charged into an electric furnace.

That is, the material is preheated from the standpoint of preventing steam explosion accidents during material charging and ensuring work safety, as well as promoting melting of the material and improving steelmaking efficiency.

Although the auxiliary burner is most commonly used as a preheating device for raw materials, this device is not preferred in today's world where energy conservation is desired.

For this reason, devices are being implemented that collect and utilize the high-temperature exhaust gas heat generated from the electric furnace between the electric furnace and the dust collector for forced discharge of the exhaust gas, but these devices have the following drawbacks. be.

That is, basically, the exhaust gas heat recovery efficiency is, for example, 20 to 30
%, and because sufficient preheating is not performed, it takes a long time to make steel.On the other hand, if we try to improve this recovery efficiency, the preheating equipment will become larger and more complicated, which will increase the equipment price. In the end, the energy saving effect cannot be achieved.

However, increasing the size of the preheating device will lengthen the cycle time for supplying and discharging materials to the preheating device, which is contrary to the shortening of melting time accompanying the rapid progress of current steelmaking technology. This was not a desirable situation.

In addition, in conjunction with the above-mentioned demand for shortening the cycle time, conventional preheating devices are complicated to operate;
There were safety issues.

Furthermore, with conventional preheating devices, exhaust gas heat recovery is not sufficient, so the gas discharged into the atmosphere is relatively high temperature (150°C, for example), and therefore there is a lot of oil mist etc. in the exhaust gas. These oil mist and the like are contained in a gaseous state and are discharged into the atmosphere together with exhaust gas, producing so-called white smoke and causing air pollution.

The present invention was created in view of the above-mentioned problems, and the first object of the present invention is to use the exhaust gas heat of steel manufacturing equipment to preheat the raw material to the equipment, for example, about 70%
The purpose is to shorten the melting time, that is, the steel manufacturing time, by effectively utilizing the steel material to the extent of approximately 10% and sufficiently preheating the steel material.

Another object of the present invention is to provide a device for preheating raw material with a simple and compact structure, and to keep equipment construction costs low.

Still another object of the present invention is to facilitate and shorten the work of supplying and discharging the material to the preheating device, and to sufficiently preheat the material within a range that can keep up with the melting time. .

Still another object of the present invention is to recover and decompose substances contained in exhaust gas that cause air pollution in a preheating device, thereby preventing the occurrence of pollution as much as possible.

The present invention is characterized in that, in a preheating device that introduces exhaust gas from an electric furnace into a plurality of preheating tanks in series to preheat the material in the preheating tanks, the preheating tanks are arranged on a fixed side. a fixing tank with an upward opening provided in the fixing tank, and the fixing tank is inserted and removed from the opening of the fixing tank,
The upper part has a supply port for receiving the material, and the lower part has a movable tank with a discharge port that can be opened and closed to discharge the material and allow exhaust gas to pass through, and the supply port of the movable tank can be opened and closed. It consists of an upper lid to cover and a transfer device for horizontally moving the upper lid, an exhaust gas inlet is provided in the upper lid of each of the preheating tanks, an exhaust gas outlet is provided in the fixed tank, and an exhaust gas discharge part of the electric furnace. The inlet pipe connected to is connected to each exhaust gas inlet through a first on-off valve, and the exhaust gas outlet of the own preheating tank and the exhaust gas inlet of another preheating tank are connected via a second on-off valve to a connecting pipe. and each exhaust gas outlet is connected to an exhaust pipe for external discharge via a third on-off valve. The point is that it is placed in a predetermined position and controlled so that it can pass through.

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

First, to explain the first embodiment shown in FIGS. 1 to 5, in FIG.
For example, a pipe line is installed between an electric furnace and a baghouse 3 that collects dust from the exhaust gas discharged from the steelmaking equipment 2, and an exhaust fan 4 is installed between the preheating device 1 and the baghouse 3. Li, the exhaust gas is drawn into the piping line and forced to flow.

The preheating device 1 is a device that preheats charging materials such as scrap, ferroalloy, directly reduced iron, lime, etc. in the steelmaking equipment 2 with heat generated from the exhaust gas of the equipment, and accommodates and discharges the charging materials. It has a plurality of preheating tanks 5, although there are two tanks in the illustrated example.

The exhaust gas discharge section 6 of the steelmaking equipment 2 and the exhaust gas inlet section 7 of each preheating tank 5 are connected by branched introduction pipes 8, and the introduction pipes 8
A vertical gas distribution tower 9 is installed near the steelmaking equipment 2,
Further, in the introduction pipe 8 between the exhaust gas discharge section 6 and the exhaust gas inlet section 7 of each preheating tank 5, a butterfly-type electric or cylinder-driven first on-off valve 10 is interposed.

The exhaust pipe 11 is for exhausting the exhaust gas that has finally passed through the preheating tank 5, and connects the exhaust gas outlet 12 of each preheating tank 5 and the exhaust fan 4, and has a vertical gas collection in the middle. Tower 1
3, and each exhaust pipe 11 is provided with a third on-off valve 14 of the same type as the first on-off valve 10, respectively.

The connecting pipe 15 connects the second exhaust gas outlet 12a of the preheating tank 5 and the exhaust gas inlet of the other preheating tank 5 so that the exhaust gas sequentially passes through the preheating tanks 5 in series from the inlet pipe 8 to the exhaust pipe 11. 7, and in the illustrated example, the connecting pipe 15 connects to the first on-off valve 10.
A second on-off valve 16 of a similar type is provided between each preheating tank 5, respectively.

The second exhaust gas outlet section 12a is communicated with the exhaust gas outlet section 12 within the preheating tank 5.

To explain the configuration of the connecting pipe 15 more specifically, the second exhaust gas outlet portion 12a of each preheating tank 5, the introduction pipe 8 between the exhaust gas inlet portion 7 of the preheating tank 5 and the first on-off valve 10,
are connected by a communication pipe 15a, first and second outlet valves 16a and 16b are provided in series in the pipeline of each communication pipe 15a, and a communication pipe 15a between these first and second outlet valves 16a and 16b,
15a are interconnected by a common pipe 15b.

Here, if the first outlet valve 16a is a valve closer to the preheating tank 5, one of the preheating tanks 5 (the left side in the figure) is A tank A, and the other (the right side in the figure) is B tank B. , one of the connecting pipes 15 mutually provided between each preheating tank 5 is connected to the second exhaust gas outlet part 12a of tank A, and is shared with the communicating pipe 15a of the part having the first outlet valve 16a. It is composed of a pipe 15b and a communicating pipe 15a that is connected to the introduction pipe 8 of tank B and has a second outlet valve 16b, and in this case, the first and second outlet valves 1
6a and 16b are the second on-off valves 1 in this connecting pipe 15.
6.

The other connecting pipe 15 is constituted by a pipe line extending from the second exhaust gas outlet section 12a of the B tank B to the introduction pipe 8 of the A tank A, as described above.

The on-off valves 10, 14, 16 are operated to open and close according to an electrical program or the like so that the exhaust gas sequentially passes through the preheating tanks 5 of the selectably selected order in series.

To explain the route of this exhaust gas based on the diagram, the first on-off valve 10 and first outlet valve 16a on the A side of tank A, and the second outlet valve 16b and third on-off valve 14 on the side of tank B are all "open". When the valves and other valves are closed, the exhaust gas from the steelmaking equipment 2 first enters tank A through the introduction pipe 8, as shown by the dotted line in the figure, and the charged material contained in tank A. After passing through the connecting pipe 15
, and enters tank B through the tank B and the exhaust pipe 11
It passes through and is sucked into the exhaust fan 4, and then the baghouse 3
After being subjected to dust collection processing, it is discharged into the atmosphere.

By opening and closing each of the on-off valves 10, 14, and 16 in the opposite manner to the above, the exhaust gas is passed from tank B to tank A in series.

During this time, the dust in the exhaust gas is inertially collected in the gas distribution tower 9 and the gas collection tower 13, and the settled dust is removed from each group 9, 13 as appropriate.

On the other hand, the gas distribution tower 9 and the gas collecting tower 13 are connected to the fourth on-off valve 17.
A direct connection pipe 18 is provided which is directly connected to the fourth on-off valve 17 through a pipe, and the fourth on-off valve 17 is normally closed, but when the preheating device 1 is not in use, the fourth on-off valve 17 is opened. Then, each first on-off valve 10 is closed and the exhaust gas is discharged via the exhaust fan 4, baghouse 3, etc.

In addition, each pipe is lined with fireproof lining as appropriate.
And/or processing for water cooling is performed.

In addition, in the illustrated example, two types of preheating tanks 5 are shown, but there may be more than this, and in any case, the various types 5 are connected in series with the introduction pipe 8, the connecting pipe 15, and the exhaust pipe 11, Each on-off valve 10. 14. 16, these on-off valves 10
, 14 and 16, the exhaust gas is configured to sequentially pass through the preheating tanks 5 of the selected order in series.

In FIGS. 2 to 5, the preheating tank 5 includes a cylindrical fixed tank 20 provided on the floor surface 19, which is a fixed side, and having a vertical axis and an upward opening, and a part that accommodates performer materials, The upper part is the righteous material supply port 21. , a movable tank 24 whose lower part is a discharge port 23 having a bottom cover 22 that can be opened and closed, and which is inserted into the fixed tank 20 so as to be inserted and removed by vertical movement;
and an upper lid 25 that can be opened and closed by horizontal movement to cover the supply port 21.

The movable tank 24 is, as shown in FIG.
An annular lid 24b is protruded from the outer periphery of the main body 24a, and when the movable tank 24 is inserted into the fixed tank 20, the annular lid 2
4b closes the annular opening between these two vessels 20,24.

The bottom cover 22 also includes a pair of planar semicircular members 22a, 22.
When the bottom lid 22 is in the closed position, the material for performing artists is accommodated and held in the main body 24a, and when the bottom lid 22 is in the open position (as shown by the two-dot chain line in FIG. 5), the charged materials are discharged. be done.

A hook 27 that is hung on a crane 26 is pivotally connected to the main body 24a, and the crane 26 moves the main body 24a and the bottom cover 2.
2 are integrally movable.

Further, the upper lid 25 has a truncated conical cylindrical shape, and a lower large-diameter portion is detachably attached to the main body 24a via a sealing member.

The introduction pipe 8 includes a fixed introduction pipe 8b extending from the steel manufacturing equipment 2 and having a pipe end 8a with a horizontal axis, and a fixed introduction pipe 8b.
The movable introduction pipe 8C can be freely connected to the movable introduction pipe 8C. It is vertically slidably connected to the pipe 8C via a seal member.

In addition, the tube end 8a of the fixed introduction tube 8b and the movable introduction tube 8C
A cylindrical connecting body 28 is fitted onto one of the horizontal ends of the connecting body 2 through a cylinder 29 so as to be slidable in the axial direction.
8 is removably fitted into the other introduction pipe by sliding, and these two introduction pipes 8b and 8C can be freely connected.

On the other hand, the connecting pipe 15 and the exhaust pipe 11 are connected to the lower part of the fixed tank 20 at symmetrical positions in the radial direction, and the exhaust gas passes through the upper lid 25 from the inlet pipe 8, as shown by the solid arrow in FIG. Then, it is made to flow into the main body 24a, passes between the charged materials in the main body 24a (not shown), and is discharged through the gap between the main body 24a and the bottom cover 22, and the connecting pipe 15 or the exhaust pipe 11. .

The transfer device 30 transfers the preheating tanks 5 adjacent to each other with each preheating tank 5 in between.
, 5, and a cart 32 that moves self-propelled on the horizontal rail 31, and the cart 32 has wheels 33 that roll on the horizontal rail 31.
An electric device 34 for driving the wheels 33 is provided.

The movable introduction pipe 8C is fixed to the truck 32 and is horizontally movable along the horizontal rail 31, and the upper lid 25 is vertically movable by a lifting device 35 provided on the truck 32. The introduction pipe 8C and the upper lid 25 are movable by the transfer device 30 to a position that allows the movable tank 24 to be inserted into and removed from the fixed tank 20, particularly to allow vertical movement.

Furthermore, the respective carts 32 corresponding to these preheating tanks 5 are movable alternately on the horizontal rails 31 between the face heating tanks 5 (positions indicated by two-dot chain lines in FIGS. 2 and 3).

In the illustrated example, the connecting body 28 is fitted into a movable introduction pipe 8C, and a cylinder 29 for operating the connecting body 28 is provided on a frame on a carriage 32.

The lifting device 35 also includes an electric motor 36 provided on the cart 32, a hoisting shaft 37 that is rotated by the electric motor 36 by a chain drive, and an upper lid 25 that is wound around the hoisting shaft 37.
It is mainly composed of a winding rope body 38 such as a chain connected to the winding rope body 38.

Therefore, when the movable tank 24 is separated from the fixed tank 20, the movable tank 24 is separated from the inlet pipe 8, the connecting pipe 15, and the exhaust pipe 11, and conversely, the movable tank 24 is separated from the fixed tank 20. By inserting and attaching the upper lid 25 to the movable tank 24, the movable tank 24 is connected to the container tubes 8.11, 15.

In addition, each part of the preheating tank 5 has the same shape and size, and the movable tank 2
4 is interchangeable with that of another preheating tank 5.

Next, a method of operating the preheating device 1 based on the above configuration will be explained.

Entertainer materials, such as scraps, are supplied to the movable tank 24 removed from the fixed tank 20 by a crane 26 or the like using a dump truck, a magnetic crane, etc., and stored in the movable tank 24.

Next, this movable tank 24 is inserted into the fixed tank 20, the transfer device 30, which had been moved horizontally in advance, is returned to the top of the movable tank 24, the upper lid 25 is lowered by the lifting device 35, and the supply port 21 is opened. At the same time, the movable tank 24 and the introduction pipe 8 are connected.

At the same time, the connecting body 28 is slid and the fixed introduction pipe 8 is
b to connect the fixed introduction pipe 8b and the movable introduction pipe 8C.

In this way, the movable tanks 24 each containing the charging material
is inserted into the corresponding fixed tank 20, and the container tubes 8, 11, 1
5, then the first to third on-off valves 10, 14,
16, the exhaust gas from the steel manufacturing equipment 2 passes through A-tank A and B-tank B sequentially in series and is discharged from the baghouse 3, as shown in FIG. 1, for example.

In this case, A-tank A will be preheated with higher temperature exhaust gas than B-tank B.

Then, once the preheating of the charging material in tank A is completed,
The upper lid 25 of several types A is attached to the transfer device 3 together with the movable introduction pipe 8C.
0, the movable tank 24 is moved away from the type A, the movable tank 24 is moved onto the steel making equipment 2, and the preheated charging material is filled into the steel making equipment 2 by opening the bottom cover 22.

During this time, another movable tank 24, which has previously housed the charging material, is inserted into the fixed tank 20 of tank A, and the container tubes 8, 11
．． 15.

Next, by operating the first to third on-off valves 10, 14, and 16,
Contrary to the above, the exhaust gas is made to pass through the B tank B and the A tank A sequentially in series.

In this case, since the charging material in tank B has been preheated to some extent, the preheating is completed in a short period of time and sufficient preheating is achieved.

Moreover, the sensible heat of the exhaust gas after passing through tank B is sufficiently given to the charging material of tank A, and the heat of the exhaust gas is effectively recovered.

Furthermore, the timing of filling the preheated charging material from the movable tank 24 into the steelmaking equipment 2 is matched with the timing of attaching the movable tank 24 filled with the charging material to be newly preheated to the fixed tank 20. As a result, the waiting time during the process is shortened and a sufficient preheating period can be taken, resulting in good work efficiency.

Furthermore, as the flow progresses downstream, the exhaust gas temperature increases to, for example, 100°C.
Since the charging material in the downstream preheating tank 5 is at a low temperature, the exhaust gas at this location is below the dew point, and moisture such as oil mist condenses on the surface of the low-temperature charging material. As a result, oil mist, etc., which is a source of secondary pollution in exhaust gas, is recovered.

Then, during the next stage of preheating the charging material, the oil mist etc. recovered is oxidized and decomposed by exhaust gas at a high temperature of about 750 degrees Celsius, reducing overall emissions of pollutants into the atmosphere. .

6 and 7, the figures show another embodiment of the transfer device 30, in which a post 39 is provided protruding from the floor surface 19, and the top of the post 39 is rotated about a vertical axis via a gear device 40. A freely pivoting member 41 is provided.

The movable introduction tube 8C is fixed to the rotating member 41 in the same manner as in the embodiment described above, and the upper lid 25 is provided so as to be vertically movable via the lifting device 35.
approaches the fixed introduction pipe 8b and the movable tank 24 in a horizontal direction, drawing an arcuate trajectory, and can be freely connected to each other (the sixth
(as shown in the figure), and can be freely separated by drawing the same circular arc trajectory (as shown in the seventh figure).

In FIG. 8, the figure shows still another embodiment, in which the exhaust gas outlet section 12 is single in each preheating tank 5, and the exhaust pipe 11 between the exhaust gas outlet section 12 and the third on-off valve 14, The first on-off valve 10 from the exhaust gas inlet section 7 in the other preheating tank 5
The introduction pipes 8 between the two are connected to each other by connecting pipes 15, and each connecting pipe 15 is provided with a second on-off valve 16, respectively.

Further, the exhaust pipe 11 and the lower part of the gas distribution tower 9 are directly connected via a fourth on-off valve 17.

Then, the fourth on-off valve 17 is normally closed, and the on-off valve 1
With the operations of 0.14 and 16, the exhaust gas sequentially passes through the preheating tank 5 in series, for example as shown by the dotted line in FIG.

The other configurations and operations are substantially the same as in the previous embodiment.

Next, an example of the temperature distribution and air volume distribution during the preheating operation with the configuration shown in FIG. 8 will be shown.

However, tank A is on the upstream side of tank B.

In the above case, the gradual increase in the amount of exhaust gas toward the downstream is due to leakage from the outside into the piping line.

The present invention is as described above, and next, the effects of the present invention and the prior art will be compared.

(1) In terms of efficiency; (2) In terms of overall effect (Example) According to the present invention, since the preheating tanks 5, 5 are connected in series, the sensible heat of the exhaust gas is effectively utilized; Therefore, since the charging material is sufficiently preheated, the steel manufacturing time is advantageously shortened.

In addition, the portion of the preheating tank 5 that accommodates the charging material is mutually exchangeable with the same portion of other preheating tanks 5, and the exhaust gas sequentially passes through the preheating tanks 5 in the selected order in series. Because of this structure, operations such as supplying and discharging the charging material to the preheating tank 5 are facilitated, and the charging material can be sufficiently preheated in a short time.

Furthermore, oil mist, etc., which is a source of secondary pollution in the exhaust gas, is collected in the preheating tank 5 on the downstream side, and when this preheating tank 5 is placed on the upstream side, the oil mist, etc. collected is oxidized and decomposed. This is beneficial because the generation of pollution is suppressed.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view showing an embodiment of the present invention, FIG. 2 is a front sectional view taken along the line II-II of FIG. 1, and FIG.
4 is a side view of FIG. 2, FIG. 5 is an enlarged partial sectional view of the preheating tank, FIG. 6 is a front view of another embodiment of the transfer device, and FIG. 7 is the same front view. FIG. 8 is an overall perspective view showing still another embodiment of the present invention. 1... Preheating device, 2... Steel manufacturing equipment, 5
..... Preheating tank, 6 ..... Exhaust gas discharge section, 7
...Exhaust gas inlet section, 8...Introduction pipe, 1
0...First on-off valve, 11...Exhaust pipe,
12... Exhaust gas outlet section, 14... Third
Opening/closing valve, 15...Connecting pipe, 16...Second
Opening/closing valve, 20...Fixed tank, 24...Movable tank, 25...Upper lid, 30...Transfer device.

Claims (1)

[Claims] 1. In a preheating device that introduces exhaust gas from an electric furnace into a plurality of preheating tanks in series to preheat charging materials in the preheating tanks, the preheating tank 5 is provided on a fixed side. The fixed tank 20 has an upper opening, and is inserted into and removed from the opening of the fixed tank 20, and has a supply port 21 at the upper part for receiving the charged material, and a lower part for discharging the material and exhaust gas. A movable tank 24 having a discharge port 23 that can be opened and closed to allow passage through it, and an upper lid 2 that can open and close the supply port 21 of the movable tank 24.
5 and a transfer device 30 for horizontally moving the upper lid 25, the upper lid 25 of each preheating tank 5 is provided with an exhaust gas inlet part 7, the fixed tank 20 is provided with an exhaust gas outlet part 12, and an electric furnace. The introduction pipe 8 connected to the exhaust gas discharge part 6 of the second
It is connected to each exhaust gas intake section 7 through an on-off valve 10, and the exhaust gas outlet section 12 of its own preheating tank 5 and the exhaust gas inlet section 7 of another preheating tank 5 are connected via a second on-off valve 16 to a connecting pipe 15. and each exhaust gas outlet part 12 is connected to the exhaust pipe 11 for external discharge via the third on-off valve 14, and each on-off valve 10, 14. 1. A preheating device for steelmaking charging material, characterized in that it is arranged at a predetermined position and controlled so that it can pass through tanks 5, 5 in series in any combination. 2. The introduction pipe 8 is divided into a fixed introduction pipe 8b and a movable introduction pipe 8C that can be freely connected to the fixed introduction pipe 8b, the movable introduction pipe 8C is fixed to the horizontally movable transfer device 30, and the upper lid 25 is The upper lid 25 is connected to the movable introduction tube 8C so as to be vertically movable, and the upper lid 25 is provided on the transfer device 30 so as to be vertically movable.
2. The preheating device for steelmaking charging material according to claim 1, wherein the transfer device 30 allows the movable tank 24 to be moved to a position where it is inserted into and removed from the fixed portion 20. 3. A cylindrical connecting body 28 is fitted onto either the fixed introduction pipe 8b or the movable introduction pipe 8C so as to be slidable in the axial direction, and the coupling body 28 is slidably fitted into the other introduction pipe and removably fitted thereto. 3. The preheating device for steelmaking charging material according to claim 2, wherein both the grooved pipes 8b and 8C are connected. 4. Claim 3, characterized in that the transfer device 30 has a cart 32 that moves on a horizontal rail 31.
A preheating device for charging material for steelmaking as described in 2. 5 A horizontal rail 31 is installed across the adjacent preheating tanks 5, 5, and each trolley 32, 32 corresponding to these preheating tanks 5, 5
5. The preheating device for steelmaking charging material according to claim 4, wherein the preheating device is configured to be able to move alternately on a rail 31 between the two-hand heat tanks 5, 5. 6 The transfer device 30 rotates around the vertical axis with the rotating member 4
1. A preheating device for steelmaking charging material according to claim 3, characterized in that the device comprises: 1.