A method for preheating furnace burden of submerged arc furnace and a preheating device

Abstract

The present invention provides a method for preheating the furnace burden of a submerged arc furnace. A preheating channel is arranged in a sealed cavity between the feeding mechanism of the submerged arc furnace and the furnace body of the submerged arc furnace. Its inner side is isolated from the electrodes in the furnace, and the outer side enables flue gas to flow between the preheating channel and the sealed cavity; a feeding tray is fixed below the feeding mechanism, and a number of feeding holes are arranged on the feeding tray. The preheating channel surrounds all the feeding holes; when the material enters the furnace body of the submerged arc furnace from the feeding mechanism, it first passes through the feeding holes and then through the preheating channel. The high-temperature gas generated in the furnace body of the submerged arc furnace rises and first enters the preheating channel from the bottom and around of the preheating channel to preheat the material in the preheating channel; part of the harmful substances on part of the high-temperature gas passing through the preheating channel are adsorbed on the material and enter the furnace body of the submerged arc furnace for smelting along with the material. Part of the high-temperature gas continues to rise to preheat the material in each feeding hole and is recovered by a waste heat recovery device. The present invention also provides a preheating device to improve the energy utilization rate.

Description

Technical Field

[0001] The present invention relates to the field of submerged arc furnace equipment, and particularly relates to a preheating device for the furnace charge of a submerged arc furnace. Background Art

[0002] A submerged arc furnace is also known as an electric arc furnace or a resistance furnace. It is mainly used for reducing and smelting ores, carbonaceous reducing agents, and solvent raw materials. It mainly produces ferroalloys such as ferrosilicon, ferromanganese, ferrochrome, ferrotungsten, and silicomanganese alloy, and is an important industrial raw material in the metallurgical industry and chemical raw materials such as calcium carbide. Submerged arc furnaces can be divided into semi-closed submerged arc furnaces and fully closed submerged arc furnaces. The flue gas of a fully closed submerged arc furnace has high physical sensible heat and chemical energy. The flue gas temperature is as high as over 850°C, the proportion of CO in the flue gas is about 60% - 80%, and there are other substances such as gas with a relatively high calorific value. Currently, the waste heat utilization of fully closed submerged arc furnaces mainly focuses on recovery. This utilization method can only utilize part of the flue gas and cannot utilize other substances such as gas with a relatively high calorific value, resulting in a great waste of energy after recovery. Summary of the Invention

[0003] To solve the problem of waste heat utilization of submerged arc furnaces in the prior art, the present invention proposes a preheating device for the furnace charge of a submerged arc furnace.

[0004] The technical solution of the present invention is realized as follows:

[0005] A preheating method for the furnace charge of a submerged arc furnace. A preheating channel is arranged in a sealed cavity between the feeding mechanism of the submerged arc furnace and the furnace body of the submerged arc furnace. The inner side of the preheating channel is isolated from the electrodes in the furnace, and the outer side enables the flue gas to flow between the preheating channel and the sealed cavity; a feeding tray is fixed below the feeding mechanism, and a number of feeding holes are arranged on the feeding tray, and the preheating channel surrounds all the feeding holes;

[0006] When the material enters the furnace body of the submerged arc furnace from the feeding mechanism, it first passes through the feeding holes and then through the preheating channel. The high-temperature gas generated in the furnace body of the submerged arc furnace rises and first enters the preheating channel from the bottom and around of the preheating channel to preheat the material in the preheating channel; some harmful substances on a part of the high-temperature gas passing through the preheating channel are adsorbed on the material and enter the furnace body of the submerged arc furnace for smelting along with the material. A part of the high-temperature gas continues to rise to preheat the material in each feeding hole, and finally is recovered by a waste heat recovery device.

[0007] Preferably, a smoke exhaust pipe is arranged on the feeding mechanism, and the smoke exhaust pipe is connected to the waste heat recovery device. A part of the high-temperature gas passing through the preheating channel in the furnace body of the submerged arc furnace passes through the feeding holes and then through the feeding mechanism during the recovery process, preheats the material in the feeding mechanism, and then is recovered to the waste heat recovery device.

[0008] A preheating device for the preheating method of the charge of a submerged arc furnace is provided with a blanking plate, a partition board and a ventilation grid in a sealed cavity between the blanking mechanism of the submerged arc furnace and the furnace body of the submerged arc furnace. The blanking plate is fixed at the bottom end of the blanking mechanism. A plurality of blanking holes are arranged on the blanking plate, and the plurality of blanking holes are communicated with the blanking port of the blanking mechanism. The partition board and the ventilation grid are fixed at the bottom end of the blanking plate. The partition board surrounds the outside of the electrode in the furnace and is located inside the blanking holes. The ventilation grid is located outside the blanking holes, and a preheating channel is formed between the ventilation grid and the partition board.

[0009] Preferably, a smoke exhaust pipe is arranged on the blanking mechanism. The smoke exhaust pipe is communicated with the blanking port of the blanking mechanism, and the smoke exhaust pipe is connected to a waste heat recovery device.

[0010] Preferably, a plurality of bottom plates are hinged to the bottom of the ventilation grid. A hoisting rope is arranged at the top of each bottom plate, and the plurality of hoisting ropes are fixed on a hoisting device. After all the bottom plates are closed, the preheating channel between the ventilation grid and the partition board is closed.

[0011] Preferably, the ventilation grid is arranged as a regular-shaped steel wire mesh with a closed head and tail and more than one independent circular-shaped steel wire mesh.

[0012] Preferably, the partition board is arranged as a heat-insulating board.

[0013] Preferably, the smoke exhaust pipe includes a branch pipe and an annular main pipe. A plurality of branch pipes are arranged on the blanking mechanism. The tops of all the branch pipes are communicated with the annular main pipe, and the annular main pipe is connected to a waste heat recovery device.

[0014] The beneficial effects of the present invention are as follows: For the preheating method of the charge of the submerged arc furnace of the present invention, the high-temperature gas generated in the furnace body of the submerged arc furnace rises and first enters the preheating channel from the bottom and around of the preheating channel to preheat the materials in the preheating channel. Some harmful substances on a part of the high-temperature gas passing through the preheating channel are adsorbed on the materials and enter the furnace body of the submerged arc furnace for smelting along with the materials. A part of the high-temperature gas continues to rise to preheat the materials in each blanking hole, and finally is recovered by the waste heat recovery device. It can improve the utilization of harmful substances and reduce the emission of harmful substances. For the preheating device for the preheating method of the charge of the submerged arc furnace of the present invention, a preheating channel is formed by using the blanking plate, the ventilation grid and the partition board. The blanking holes on the blanking plate extend the preheating channel, make full use of the high-temperature gas generated in the furnace body of the submerged arc furnace, and reduce the emission of harmful substances. Description of the Drawings

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 It is a schematic diagram of the overall structure of a preheating device for a preheating method of furnace burden in a submerged arc furnace according to the present invention;

[0017] Figure 2 It is a schematic diagram of a partial structure of a preheating device for a preheating method of furnace burden in a submerged arc furnace according to the present invention;

[0018] Figure 3 It is a schematic diagram of the bottom structure of a preheating device for a preheating method of furnace burden in a submerged arc furnace according to the present invention;

[0019] Figure 4 is Figure 3 a schematic diagram of the structures of the air-permeable fence and the partition board shown.

[0020] In the figure:

[0021] 1. Feeding mechanism; 2. Submerged arc furnace body; 3. Preheating channel; 4. Feeding tray; 5. Smoke exhaust pipe; 6. Partition board; 7. Air-permeable fence; 8. Bottom plate; 9. Lifting rope; 41. Feeding hole. Specific embodiments

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0023] Embodiment: As Figure 1 and Figure 2As shown in the figure, there is a preheating method for the burden of a submerged arc furnace. A preheating channel 3 is arranged in the sealed cavity between the feeding mechanism 1 of the submerged arc furnace and the furnace body 2 of the submerged arc furnace. The inner side of the preheating channel 3 is isolated from the electrodes in the furnace, and the outer side enables flue gas to flow between the preheating channel and the sealed cavity; a feeding tray 4 is fixed below the feeding mechanism 1, and a number of feeding holes 41 are arranged on the feeding tray 4. The preheating channel 3 surrounds all the feeding holes; when the material enters the furnace body 2 of the submerged arc furnace from the feeding mechanism 1, it first passes through the feeding holes 41 and then through the preheating channel 3. The high-temperature gas generated in the furnace body 2 of the submerged arc furnace rises and first enters the preheating channel 3 from the bottom and around of the preheating channel to preheat the material in the preheating channel 3; some harmful substances in a part of the high-temperature gas passing through the preheating channel are adsorbed on the material and enter the furnace body of the submerged arc furnace for smelting along with the material. A part of the high-temperature gas continues to rise to preheat the material in each feeding hole and is finally recovered by the waste heat recovery device. It can improve the utilization of harmful substances and reduce the emission of harmful substances.

[0024] As Figure 1 and Figure 2 shown in the figure, a smoke exhaust pipe 5 is arranged on the feeding mechanism 1. The smoke exhaust pipe 5 is connected to the waste heat recovery device. A part of the high-temperature gas passing through the preheating channel in the furnace body 2 of the submerged arc furnace passes through the feeding holes and then through the feeding mechanism during the recovery process, preheats the material in the feeding mechanism and is recovered to the waste heat recovery device, extending the preheating channel to make full use of the heat of the high-temperature gas in the furnace body of the submerged arc furnace.

[0025] As Figures 1 to 3 shown, the preheating device for the preheating method of the burden of the submerged arc furnace. A feeding tray 4, a partition plate 6 and a ventilation grid 7 are arranged in the sealed cavity between the feeding mechanism 1 of the submerged arc furnace and the furnace body 2 of the submerged arc furnace. The feeding tray is fixed at the bottom end of the feeding mechanism. A number of feeding holes 41 are arranged on the feeding tray 4, and a number of feeding holes are communicated with the feeding port of the feeding mechanism; the partition plate 6 and the ventilation grid 7 are fixed at the bottom end of the feeding tray. The partition plate 6 surrounds the outside of the electrodes in the furnace and is located inside the feeding holes. The ventilation grid 7 is located outside the feeding holes, and a preheating channel is formed between the ventilation grid 7 and the partition plate 6. A smoke exhaust pipe 5 is arranged on the feeding mechanism 1, and the smoke exhaust pipe 5 is communicated with the feeding port of the feeding mechanism and is connected to the waste heat recovery device. The preheating channel is located above the furnace body of the submerged arc furnace. The high-temperature gas generated in the furnace body of the submerged arc furnace rises and first enters the preheating channel 3 from the bottom and around of the preheating channel to preheat the material in the preheating channel 3. When rising into the feeding mechanism, it preheats the material in the feeding mechanism through the smoke exhaust pipe, extends the preheating channel, effectively utilizes the discharged heat and reduces the heat loss during the discharge process.

[0026] The isolation plate 6 is used to separate the electrodes in the furnace and the preheating channel. The air-permeable fence 7 is located in the sealed cavity between the feeding mechanism 1 and the submerged arc furnace body 2, so that the high-temperature gas and other substances in the submerged arc furnace enter the preheating channel through the air-permeable fence, enter the feeding hole through the preheating channel, and then pass through the feeding mechanism after passing through the feeding hole and enter the exhaust pipe for recovery. The isolation plate is set as a heat-insulating plate, which has a heat-insulating function for the preheating channel.

[0027] As Figure 4 shown, several bottom plates 8 are hinged to the bottom of the air-permeable fence 7, and a lifting rope 9 is arranged on the top of each bottom plate 8. Several lifting ropes 9 are fixed on the lifting device; the preheating channel between the air-permeable fence and the isolation plate is closed after all the bottom plates are closed. When it is not necessary to feed materials into the submerged arc furnace body through the preheating channel, the preheating channel is closed to improve the versatility of the use of the preheating channel.

[0028] As Figure 4 shown, the air-permeable fence 7 is set as a regular-shaped steel mesh with a closed head and tail and more than one independent circular-shaped steel mesh. When there are peripheral feeding holes on the feeding tray, this structure can not only increase the contact surface of the preheating channel, but also be convenient for installation, and also reduce the space occupation rate, which is very convenient for use in a closed submerged arc furnace.

[0029] As Figure 3 shown, the exhaust pipe 5 includes a branch pipe and an annular main pipe. Several branch pipes are arranged on the feeding mechanism, the tops of all the branch pipes are connected to the annular main pipe, and the annular main pipe is connected to the waste heat recovery device. Multiple branch pipes on the feeding mechanism enable the high-temperature gas to fully preheat the materials in the feeding mechanism in all directions, and make more efficient use of the high-temperature gas and other high-temperature substances in the submerged arc furnace body.

[0030] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preheating the furnace charge of a submerged arc furnace, characterized in that, A preheating channel is arranged in the sealed cavity between the feeding mechanism of the submerged arc furnace and the furnace body of the submerged arc furnace. The inner side of the preheating channel is isolated from the electrodes in the furnace, and the outer side enables flue gas to flow between the preheating channel and the sealed cavity; a feeding tray is fixed below the feeding mechanism, and a plurality of feeding holes are arranged on the feeding tray, and the preheating channel surrounds all the feeding holes; When the material enters the furnace body of the submerged arc furnace from the feeding mechanism, it first passes through the feeding holes and then through the preheating channel. The high-temperature gas generated in the furnace body of the submerged arc furnace rises and first enters the preheating channel from the bottom and around of the preheating channel to preheat the material in the preheating channel; some harmful substances on a part of the high-temperature gas passing through the preheating channel are adsorbed on the material and enter the furnace body of the submerged arc furnace for smelting along with the material. A part of the high-temperature gas continues to rise to preheat the material in each feeding hole, and finally is recovered by the waste heat recovery device; A feeding tray, a partition board and a ventilation fence are arranged in the sealed cavity between the feeding mechanism of the submerged arc furnace and the furnace body of the submerged arc furnace. The feeding tray is fixed at the bottom end of the feeding mechanism, and a plurality of feeding holes are arranged on the feeding tray. The plurality of feeding holes are communicated with the feeding port of the feeding mechanism; the partition board and the ventilation fence are fixed at the bottom end of the feeding tray. The partition board surrounds the outside of the electrodes in the furnace and is located inside the feeding holes. The ventilation fence is located outside the feeding holes, and a preheating channel is formed between the ventilation fence and the partition board.

2. The method for preheating the burden of a submerged arc furnace according to claim 1, wherein, A smoke exhaust pipe is arranged on the feeding mechanism. The smoke exhaust pipe is communicated with the feeding port of the feeding mechanism. The smoke exhaust pipe is connected to the waste heat recovery device. A part of the high-temperature gas passing through the preheating channel in the furnace body of the submerged arc furnace passes through the feeding holes and then through the feeding mechanism during the recovery process, preheats the material in the feeding mechanism and is then recovered to the waste heat recovery device.

3. The method for preheating furnace burden of submerged arc furnace according to claim 1, wherein A plurality of bottom plates are hinged to the bottom of the ventilation fence. A lifting rope is arranged at the top of each bottom plate, and the plurality of lifting ropes are fixed on a lifting device; when all the bottom plates are closed, the preheating channel between the ventilation fence and the partition board is closed.

4. The method for preheating furnace charge of submerged arc furnace according to claim 1, characterized in that, The ventilation fence is arranged as a regular-shaped steel wire mesh with a closed head and tail and more than one independent circular-shaped steel wire mesh.

5. The method for preheating charge of submerged arc furnace according to claim 1, characterized in that The partition board is arranged as a heat-insulating board.

6. The method for preheating the charge of a submerged arc furnace according to claim 2, characterized in that, The smoke exhaust pipe includes a branch pipe and an annular main pipe. A plurality of branch pipes are arranged on the feeding mechanism. The tops of all the branch pipes are communicated with the annular main pipe, and the annular main pipe is connected to the waste heat recovery device.

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