JPH0336878Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) This invention relates to a melting furnace apparatus, and particularly to a melting furnace apparatus that supplies a predetermined amount of granular carbonaceous material to the melting furnace.

(Background Art) Conventionally, in melting furnaces such as blast furnaces and cupola furnaces, metals such as ore or scrap are charged into the furnace together with carbonaceous materials, and air is sent through the furnace to burn the carbonaceous materials.
The heat is used to melt the metal, but since the cost of this carbon material is high in the operation of the melting furnace, there is a problem that the melting cost is high. Various studies are being conducted to achieve this goal.

(Technical Issues) The present invention was developed against the background of the above circumstances, and in order to reduce melting costs, it uses powdery carbonaceous material and places the powdery carbonaceous material in the furnace. The object of the present invention is to provide a concrete pneumatic feeding system for supplying and burning granular carbonaceous material.

(Solution Means) The melting furnace apparatus according to the present invention to achieve such a problem includes a melting furnace, a blowing passage that guides air supplied from a predetermined air supply source to the melting furnace, and a predetermined amount of air supplied from a predetermined air supply source. a granular carbonaceous material supply means for supplying granular carbonaceous material; and a granular carbonaceous material supply path that guides the granular carbonaceous material supplied from the granular carbonaceous material supply means into the melting furnace. and a pressurizing blower means for providing a branch flow path in the air blow path, branching a part of the air blown in the air blow path, and pressurizing the branched air on the branch flow path. is provided, and the pressurized air from the pressure blower means is guided to the granular carbon material supply path to act on the granular carbon material supplied from the granular carbon material supply means, while the A bypass flow path that bypasses the pressure blower means is provided on the branch flow path, and a part of the pressurized air pressurized by the pressure blower is passed through the bypass flow path upstream of the pressure blower means. A flow rate control valve means is provided in the bypass flow path so that the flow rate of pressurized air returned to the upstream side of the pressurized blower means through the bypass flow path is controlled by the flow control valve means. It is designed so that it can be controlled by

(Operation/Effect) In such a melting furnace apparatus, a predetermined amount of granular carbonaceous material is supplied from the granular carbonaceous material supply means and is fed into the melting furnace through the granular carbonaceous material supply path. As granular materials like this are now fed into the melting furnace as carbon material, the temperature inside the furnace rises quickly in response to the supply of carbon material. This made it easier to control the temperature inside the furnace.

In addition, granular carbonaceous material has a high combustion efficiency and therefore increases the temperature inside the furnace, so the amount of carbonaceous material used can be reduced, and it is also possible to use low-quality charcoal. This results in a reduction in melting costs. Furthermore, in the case of cupola equipment for melting bare metals, as the temperature inside the furnace becomes higher, it becomes possible to increase the blending ratio of steel scraps etc. as raw metals. Costs have also been reduced. Moreover, since the CO gas in the furnace is enriched, the yield of ferrosilicon is improved. Enrichment of CO gas increases the reducing ability of the furnace atmosphere,
This is because oxidation loss of ferrosilicon added to the furnace for adjusting the composition of molten metal in a cupola device or the like is reduced.

In addition, in the melting furnace device according to the present invention, a part of the air blown into the melting furnace through the air passage for combustion of carbonaceous materials is branched into a branch flow passage, and is pressurized by a pressurized blower means. After being compressed, the granular carbonaceous material is transported through the granular carbonaceous material supply path and returned to the melting furnace, so even if the pressure inside the melting furnace fluctuates, the It has the feature that the amount of air blown into the furnace is always approximately constant, and in conjunction with this, a predetermined and approximately constant amount of granular carbon material is supplied into the furnace.

This is because the air pressure guided into the granular carbon material supply path to convey the granular carbon material maintains a certain amount higher than the air pressure in the ventilation path, and fluctuates to follow fluctuations in the pressure inside the melting furnace. This is because the air pressure in the air duct is adjusted in accordance with the pressure inside the furnace. In other words, if the pressure inside the furnace increases, the air pressure for transporting the granular carbonaceous material also increases, sending a nearly constant amount of air into the melting furnace, and conversely, if the pressure inside the furnace decreases, the air pressure for transporting the granular carbonaceous material increases. The air pressure for conveyance also decreases in synchrony with this, and similarly a predetermined, substantially constant amount of air is sent into the melting furnace.

As a result, even though the optimum amount of air is blown into the melting furnace from the air duct to burn the carbonaceous material, the air from the granular carbonaceous material supply channel is This prevents the amount of air supplied into the furnace by blowing from becoming irregularly larger or smaller than the appropriate amount. In addition, along with this, the amount of granular carbonaceous material transported to the melting furnace also becomes approximately constant.

By the way, the commonly thought method for feeding granular carbonaceous material into a melting furnace is to independently provide a pressurizing means such as an air compressor, and generate pressurized air with the air compressor. In this method, the pressurized air is applied to the granular carbonaceous material and sent into the melting furnace together with the granular carbonaceous material. very difficult to control. In order to reliably supply granular carbonaceous material even when the pressure inside the furnace fluctuates, it is necessary to set the pressurizing force of the air compressor, etc. based on the time when the pressure inside the furnace is at its highest. However, in this case, when the pressure inside the furnace decreases, an excessive amount of air will be sent into the furnace together with an excessive amount of granular carbonaceous material.

On the other hand, in the apparatus according to the present invention, the air pressure for conveying the granular carbonaceous material is made to fluctuate in synchronization with the pressure in the furnace, so the above-mentioned problems do not occur.

In addition, since the device according to the present invention uses a part of the air flowing in the air duct as a medium for conveying the granular carbonaceous material, it is possible to transfer the granular carbonaceous material by simply applying a small amount of driving force. In addition, since the only air sent into the melting furnace is the air sent through the air duct, it has the advantage that it is easy to adjust the overall amount of air sent into the furnace. ing.

Moreover, in the device according to the present invention, a part of the air pressurized by the pressure blower means is returned to the upstream side of the pressure blower means through the bypass passage provided in parallel with the pressure blower means. By changing the flow rate of the bypass flow path, the amount of pressurized air supplied to the granular carbonaceous material supply path can be stably and easily controlled over a wide range. There are some advantages. Although it is possible to directly control the pressurized amount of pressurized air supplied to the granular carbonaceous material supply path by controlling the operation of the pressure blower means, Therefore, it is difficult to control it. In particular, in such a melting furnace apparatus, if the difference between the pressure of the air introduced into the granular carbonaceous material supply path and the pressure inside the furnace is too large, the granular carbonaceous material conveyed within the granular carbonaceous material supply path may be damaged. As the conveyance speed increases, the problem of piping wear in the granular carbonaceous material supply path arises, so the pressure difference between the pressurized air introduced into the granular carbonaceous material supply path and the furnace pressure should preferably be approximately 5000 mmAq or less. Preferably
It is desirable to control within a low pressure range of about 2000 mmAq or less, but such
It is extremely difficult to directly control the amount of pressurized air supplied to the granular carbonaceous material supply path by controlling the operation of the pressure blower means.

(Example) Next, an example of the present invention will be described in detail based on the drawings.

FIG. 1 shows a cupola device as a melting furnace device. In this figure, the cupola device includes a cupola 10, a granular carbonaceous material supply device 12 that supplies a predetermined amount of granular carbonaceous material, an air passage 14 that sends air for combustion to the cupola 10, and a branch from the air passage 14. It has a granular carbon material supply pipe 18 as a granular carbon material supply path that connects the granular carbon material supply device 12 and the cupola 10. The cupola 10 is a general type used for melting foundry metals, and the furnace 20 is made of refractory material.
and a wind box 22 that stores the air sent through the air passage 14. From the wind box 22, the air pipe 2
4 extends, and its tip is positioned at the tuyere 26, so that the air contained and held in the wind box 22 is blown into the furnace 20 from there.

On the other hand, the granular carbonaceous material supply device 12 includes a tank 28 that accommodates granular carbonaceous material, and a screw-type delivery machine 30 disposed at the bottom of the tank 28, and the screw 32 rotates around the axis. By rotating, a certain amount of granular carbonaceous material is delivered into the supply pipe 18. As clearly shown in FIG. 2, the screw 32 of the screw type feeder 30 consists of a rotating shaft 34 of a motor 38 and a coil spring 36 fixed to the tip of the rotating shaft 34. When the spring 36 is rotated by the motor 38,
It is designed to continuously deliver granular carbonaceous material.

Further, the granular carbonaceous material supply pipe 18 extends from the lower part of the tank 28 and has its tip connected to the cupora furnace 20.
The tuyere 26 is located at the tuyere 26 to guide the granular carbon material sent out from the tank 28 to the tuyere 26.

A branch flow path 16 branched from the air blowing path 14 is connected to this granular carbonaceous material supply pipe 18, and a part of the combustion air sent through the air blowing path 14 is guided to the granular carbonaceous material supply pipe 18. It's starting to get worse. A ring blower 40 is disposed on the branch channel 16 as a pressurizing blower means for pressurizing and sending out the air guided into the branch channel 16. Pressurized air is sent by the blower 40. The air pressurized by the ring blower 40 is also transferred to the tank 2 through a communication passage 42.
It is also guided to the top of 8. Powder carbon material supply pipe 18
and the inside of the tank 28 to prevent the smooth flow of the granular carbonaceous material inside the tank 28 into the supply pipe 18 by the pressurized air led to the supply pipe 18. This is to do so.

The branch flow path 16 is provided with a bypass flow path 44 that bypasses the ring blower 40, and a part of the air pressurized by the ring blower 40 passes through this bypass flow path 44 and returns to the ring blower of the branch flow path 16. 40 and is returned to the upstream side. Further, a flow rate control valve 46 is provided on the bypass flow path 44, and a flow rate control valve 46 is provided on the bypass flow path 44.
The amount of pressurized air returned to the upstream side through the flow rate control valve 46 is adjusted by the flow rate control valve 46.

In the cupola device configured as described above, combustion air supplied from an air supply source (not shown) is temporarily stored in the wind box 22 and then blown into the furnace 20 from the tuyere 26 through the blast pipe 24. It can be done. On the other hand, from the tank 28 of the granular carbon material supply device 12, a certain amount of granular carbon material corresponding to the rotational speed of the screw 32 is delivered into the supply pipe 18, and the delivered granular carbon material is fed into the supply pipe 18. Together with the pressurized air introduced into the tube 18, it is sent into the furnace 20 through the tuyere 26. That is, the air is branched from the air passage 14, pressurized by the blower 40, and a part of it is returned to the upstream side through the bypass passage 44, so that the amount of pressurization is adjusted. The granular carbonaceous material sent into the supply pipe 18 is conveyed to the furnace 20 through the granular carbonaceous material supply pipe 18 .

Note that if the pressure of the air guided to the granular carbonaceous material supply pipe 18 is higher or lower than the pressure for feeding an appropriate amount of granular carbonaceous material, the flow rate on the bypass flow path 44 will be reduced. By operating the control valve 46,
By adjusting the amount of pressurized air returned to the upstream side through the bypass channel 44, the pressure of the air introduced into the granular carbonaceous material supply pipe 18 can be adjusted to an appropriate pressure.

In such a cupola device, cupola 1
The granular carbonaceous material injected into the furnace 20 of 0 has high combustion efficiency, and therefore the temperature inside the furnace becomes high, so the amount of carbonaceous material used is reduced, and as a granular carbonaceous material, it is possible to reduce the amount of coal waste etc. Since high-quality charcoal can be used, the melting cost can be reduced in combination. In addition, the method described above in which granular carbonaceous material is fed into the furnace by air has the advantage that the amount of carbonaceous material supplied can be easily adjusted. Instead, it becomes possible to increase the blended amount of steel scrap, which has the effect of reducing raw material costs by that much. Moreover, when granular carbonaceous material is used, the CO gas in the furnace is enriched and the reducing ability is increased, so the above device has the secondary effect of improving the yield of ferrosilicon. That is, ferrosilicon is added to the cupora furnace 20 in order to adjust the composition of the molten metal in anticipation of the amount of oxidation loss in the furnace 20, but as the reducing atmosphere becomes stronger, ferrosilicon Since the amount of oxidation loss is reduced, the yield of ferrosilicon is improved accordingly.

In addition, the above-mentioned cupola device includes a cupola furnace 20
It has a feature that the amount of air blown into the furnace 20 and the amount of granular carbonaceous material fed into the furnace 20 do not fluctuate irregularly with respect to the set amount. Air duct 14
The pressure inside the furnace 20 is controlled so that an appropriate amount of air is always blown into the furnace 20 depending on the condition inside the furnace 20. This is because the pressure of the air introduced into the carbonaceous material supply pipe 18 is always maintained at a certain amount higher than the pressure inside the furnace 20, and changes in synchronization with fluctuations in the pressure inside the furnace. That is, even if the pressure inside the furnace fluctuates, the difference between the pressure inside the furnace and the pressure introduced to the granular carbonaceous material supply pipe 18 will not fluctuate irregularly. A substantially constant amount of air is supplied. and,
Along with this, the amount of granular carbonaceous material sent into the furnace 20 by this air also becomes a predetermined constant amount, so that the combustion conditions in the furnace are always maintained appropriately.

The above device also has low energy costs for transporting the granular carbonaceous materials, and the air branched from the air passage 14 is returned to the furnace 20 to reduce the amount of air supplied into the furnace. It has the advantage of being easy to adjust. This is because a part of the air sent through the air passage 14 is used as a medium for feeding the granular carbonaceous material.

Moreover, in the device of this embodiment, the ring blower 40
A bypass flow path 44 is provided in parallel to the
A flow rate control valve 46 is provided on the bypass flow path 44, and as described above, the amount of pressurization of the air guided to the granular carbon material supply pipe 18 is controlled by operating the flow rate control valve 46. Since it has become like this,
The amount of pressurization can be continuously and stably adjusted within the capacity range of the ring blower 40. Therefore, in this example device, the amount of pressurized air is controlled within a low pressure range of about 5000 mmAq or less, and furthermore, about 2000 mmAq or less, to successfully suppress the problem of piping wear of granular carbon material. It became possible to do so.

As a means for delivering the granular carbonaceous material from the tank 28 of the granular carbonaceous material supply device 12, it is recommended to use the screw type delivery machine 30 equipped with the coil spring 36 as described above. Although desirable for achieving wear resistance, it is also possible to use a screw feeder with a conventional fin type screw instead.

Although one embodiment of the present invention has been described in detail above, the present invention can also be implemented in other embodiments. For example, as a pressurizing blower means for pressurizing air branched from an air duct,
The present invention is not limited to the ring blower described above, and it is of course possible to use other blowers, and it is also possible to use a common air passage for a plurality of cupora furnaces. Further, the cupola device to which the present invention is applied is not limited to the one shown in the above embodiment, but can be applied to various cupola devices.

In addition, based on the knowledge of those skilled in the art, within the scope of the invention, the present invention can also be applied to blast furnace equipment for melting ore, etc.
It is possible to implement the present invention with various modifications and improvements.

[Brief explanation of drawings]

FIG. 1 is a simplified diagram of a cupola device according to an embodiment of the present invention, and FIG. 2 is an enlarged front view of the main parts of the screw type feeder shown in FIG. 1. 10: Kyupora, 12: Powdered carbon material supply device, 1
4: Air blowing path, 16: Branch flow path, 18: Powder carbon material supply pipe, 30: Screw type delivery machine, 40: Ring blower (pressure blower means), 44: Bypass flow path,
46: Flow control valve.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A melting furnace, an air passage that guides air supplied from a predetermined air supply source to the melting furnace, and a granular carbon material supply that supplies a predetermined amount of granular carbon material. and a granular carbonaceous material supply path that guides the granular carbonaceous material supplied from the granular carbonaceous material supply means into the melting furnace, and a branch flow path is provided in the blowing path. , a pressurizing blower means for branching a part of the air blown in the air passage and pressurizing the branched air is provided on the branching flow path, and pressurization from the pressurizing blower means is provided. While guiding air to the granular carbon material supply path to act on the granular carbon material supplied from the granular carbon material supply means,
A bypass flow path that bypasses the pressure blower means is provided on the branch flow path, and a part of the pressurized air pressurized by the pressure blower means is passed through the bypass flow path to the pressure blower means. A flow rate control valve means is provided in the bypass flow path, and the flow rate of the pressurized air returned to the upstream side of the pressure blower means through the bypass flow path is controlled by the flow rate control valve. A melting furnace apparatus characterized in that it is controlled by a means. (2) The granular carbonaceous material supplying means is a screw-type delivery machine that is provided at the lower part of a tank containing the granular carbonaceous material and delivers the granular carbonaceous material from the tank by rotation around an axis. A melting furnace apparatus according to claim 1 of the utility model registration claim, comprising: