CN112595093B - Electrode heating process and device capable of blowing powder for electric arc furnace - Google Patents
Electrode heating process and device capable of blowing powder for electric arc furnace Download PDFInfo
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- CN112595093B CN112595093B CN202011346794.9A CN202011346794A CN112595093B CN 112595093 B CN112595093 B CN 112595093B CN 202011346794 A CN202011346794 A CN 202011346794A CN 112595093 B CN112595093 B CN 112595093B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
- F27B3/08—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces heated electrically, with or without any other source of heat
- F27B3/085—Arc furnaces
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/52—Manufacture of steel in electric furnaces
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
- F27B3/10—Details, accessories, or equipment peculiar to hearth-type furnaces
- F27B3/18—Arrangements of devices for charging
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
- F27B3/10—Details, accessories, or equipment peculiar to hearth-type furnaces
- F27B3/20—Arrangements of heating devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
- F27B3/10—Details, accessories, or equipment peculiar to hearth-type furnaces
- F27B3/22—Arrangements of air or gas supply devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/008—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases cleaning gases
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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Abstract
The invention discloses an electrode heating process and an electrode heating device for an electric arc furnace, which can spray powder, and comprises an electrode spraying and blowing integrated process and a tail gas recycling and nitrogen composite spraying and blowing process; the electrode blowing integrated process is to open a hole in the center of a graphite electrode, and insert a powder spray gun consisting of an inner layer central channel and an outer layer annular channel into a central hole of the electrode to be flush with the front end of the electrode, so that powder coming out of the inner layer central channel and protective gas coming out of the outer layer annular channel form coaxial power together and enter a molten pool; the tail gas produced in the smelting process is dedusted by a bag type dust collector, sent to an air compression station by an induced draft fan for storage, and the stored tail gas and nitrogen gas of a nitrogen gas pressure regulating station are sent to a gas mixing pressure regulating station in a certain proportion for storage, so that the mixed gas is used for blowing tank powder blanking, powder spray gun powder spraying and protective gas spraying. The invention can quickly and uniformly mix the powder and the liquid-phase melt, reduce the oxidation of the electrode and save the using amount of the reducing agent.
Description
Technical Field
The invention relates to the technical field of electric arc furnace smelting, in particular to an electrode heating process and device capable of blowing powder for an electric arc furnace.
Background
Electric arc furnaces are used as mainstream heating smelting equipment for steel and alloy smelting, ore smelting and metallurgical waste residue secondary treatment, and have various furnace types, such as a smelting reduction smelting furnace, an ore smelting furnace, a ladle refining furnace and the like. The power supply form is divided into an AC electric arc furnace and a DC electric arc furnace, and the DC electric arc furnace comprises a single-top electrode bottom electrode DC electric arc furnace, a multi-top electrode electric arc furnace and the like.
In the existing blowing adding technology, the insertion position of a spray gun is separated from the electrode heating position, powder sprayed by the spray gun inserted into a molten pool is in a local agglomeration state or floats to the surface layer of the molten pool to form foam slag, so that the powder and liquid-phase melt cannot quickly and sufficiently realize high-temperature chemical reaction, the product quality is poor, and although the smelting period is prolonged, the condition can be improved, but the smelting efficiency is reduced. Because the viscosity of the liquid phase melt is higher and the electrode and the spray gun are separately arranged, the electric arc stirring capability is poor, the sprayed powder lacks power and is dispersed to the whole molten pool, and the homogeneous chemical reaction is difficult to realize. The powder and the liquid-phase melt have density difference, the powder with small density is easily concentrated on the upper part of a molten pool to form a two-phase interface, and the thermochemical reaction efficiency is low.
The graphite electrode loss of the electric arc furnace is mainly oxidation loss, and the air or oxygen-containing gas in the molten pool can obviously increase the electrode consumption. Research shows that the oxygen concentration near the graphite electrode and the air flow speed on the surface of the graphite have obvious influence on the oxidation rate of the electrode. The unit consumption of the steel-making electrode of the electric arc furnace reaches 4-6 kg/t. molten steel, and the selling price of the graphite electrode is 20000-80000 yuan/t, so that the electrode loss is reduced, and the production cost can be greatly saved.
A large amount of tail gas is generated by smelting in the electric arc furnace and is discharged through a waste gas treatment system. The tail gas contains CO gas with higher concentration and heat quantity, and is not utilized. The CO gas has reducibility and can replace reducing agents such as coke, coal powder and the like. The general powder spraying conveying gas adopts nitrogen which is prepared by special air separation equipment. If the smelting tail gas of the electric arc furnace can be recycled to replace part of nitrogen, the consumption of the reducing agent can be reduced, and the consumption of the nitrogen can be saved.
Disclosure of Invention
The invention aims to provide an electrode heating process capable of blowing powder for an electric arc furnace, which overcomes the defects of the existing electric arc furnace smelting process, enables powder spray to be quickly and uniformly mixed with liquid-phase melt in a molten pool, improves metallurgical kinetic conditions, utilizes mixed gas of nitrogen and tail gas of the electric arc furnace as protective gas, reduces graphite electrode oxidation and saves the using amount of reducing agents.
Another object of the present invention is to provide a heating electrode assembly for an electric arc furnace that is capable of blowing powder.
The invention is realized in this way, a heating electrode process for an electric arc furnace capable of blowing powder comprises an electrode blowing integrated process and a tail gas recycling and nitrogen composite blowing process;
the electrode blowing integrated process is characterized in that a graphite electrode for heating an electric arc furnace is provided with a hole along the axis center, a powder spray gun composed of an inner layer central channel and an outer layer annular channel which are coaxially arranged is inserted into a graphite electrode center hole to be flush with the front end of the graphite electrode, and the process comprises the following steps: powder enters the molten pool from the inner layer central channel, and protective gas penetrates into the molten pool from the outer layer annular channel, so that the powder coming out of the inner layer central channel and the protective gas coming out of the outer layer annular channel form coaxial power together and go deep into the molten pool;
the tail gas recycling and nitrogen composite injection process is characterized in that the tail gas generated in the smelting process of an electric arc furnace is sent into an air pressure station for storage by an induced draft fan after being dedusted by a bag type dust collector, and the stored tail gas and the nitrogen of a nitrogen pressure regulating station are sent into a gas mixing pressure regulating station for storage in a certain proportion, so that the mixed gas is used for powder blanking of an injection tank, powder injection of a powder spray gun and protective gas injection.
The graphite electrode arc discharge can generate strong molten pool stirring force, and the sprayed powder is positioned in the arc discharge central area and can be diffused to the whole molten pool along with the arc stirring to form a uniform reaction system with liquid phase melt in the molten pool. A large amount of protective gas is blown into the molten pool from the center of the graphite electrode to drive the oxidizing gas around the graphite electrode and in the molten pool to be discharged out of the electric arc furnace.
Preferably, the powder can be added according to different process requirements, such as adding reducing agents of coke, coal powder and the like during smelting reduction and metal smelting, and adding a desulfurizing agent during molten steel refining.
Preferably, the maximum particle size of the powder is less than 500 μm.
More preferably, the maximum particle size of the powder is less than 200 μm.
Preferably, in the tail gas recycling and nitrogen compound injection process, the tail gas is mixed with nitrogen, and the component adjustment can be carried out according to the working condition of the electric arc furnace, and if the oxygen content in the tail gas is too high, the nitrogen proportion can be increased.
A heating electrode device capable of blowing powder for an electric arc furnace comprises the electric arc furnace, an electrode blowing integrated device, a tail gas recycling and nitrogen composite blowing device, a powder bin and a blowing tank;
the electrode blowing integrated device consists of a graphite electrode with an opening in the center of the axis and a powder spray gun, the graphite electrode extends into the electric arc furnace and is inserted into a molten pool, the aperture size of the center hole of the graphite electrode is matched with the outer diameter of the powder spray gun, the powder spray gun is arranged in the center hole of the graphite electrode, and the front end part of the powder spray gun is flush with the end part of the graphite electrode; the powder spray gun is composed of an inner layer central channel and an outer layer annular channel which are coaxially arranged, the inner layer central channel is a powder blowing channel, and the outer layer annular channel is an electrode shielding gas blowing channel;
the tail gas recycling and nitrogen compound injection device comprises a bag type dust collector, an induced draft fan, an air compression station, a nitrogen pressure regulating station and a mixed gas pressure regulating station, wherein an inlet of the bag type dust collector is connected with a waste gas discharge port of an electric arc furnace, an outlet of the bag type dust collector is connected with an inlet of the induced draft fan through a pipeline and a valve, an outlet of the induced draft fan is connected with an inlet of the air compression station through a pipeline, and an outlet of the air compression station and an outlet of the nitrogen pressure regulating station are respectively converged into a mixed gas pipeline through respective gas conveying pipelines and valves and are connected with an inlet of the mixed gas pressure regulating station;
the outlet of the powder bin is connected with the powder inlet of the blowing tank, and the powder-carrying air outlet of the blowing tank is connected with the central channel inlet of the powder spray gun through a powder distributor;
the pipeline at the outlet of the gas mixing and pressure regulating station is divided into three branches, a first branch pipeline for gas mixing and supplying is connected with a compressed air inlet of the blowing tank, the upper part and the lower part of the blowing tank are provided with compressed air inlets, a second branch pipeline for gas mixing and supplying is connected with an inlet of the powder distributor, and a third branch pipeline for gas mixing and supplying is connected with an annular channel inlet of the powder spray gun;
and valves are arranged on the first branch pipeline for gas mixing and supplying, the second branch pipeline for gas mixing and supplying and the third branch pipeline for gas mixing and supplying.
Preferably, the outlet of the powder bin is connected with the powder inlet of the blowing tank through a distributor.
Preferably, the base body of the powder spray gun is made of high-temperature-resistant ceramic materials, such as silicon carbide and silicon nitride, and can bear a high-temperature environment above 1600 ℃.
The invention has the following advantages and beneficial effects:
1. the electrode heating process for the electric arc furnace capable of blowing the powder adopts an electrode blowing integrated design, the powder spray gun with double channels is arranged in a central hole of the axis of the graphite electrode, the powder is sprayed into a molten pool and is diffused to the whole molten pool along with the stirring force of a powerful electric arc, the mixing uniformity of the melt and the powder is obviously improved, and the high-temperature chemical reaction is more sufficient and rapid. Compared with the existing electrode heating and powder injection separate technology, the single-furnace operation period is obviously shortened, the electric energy consumption is saved, and the machine-hour yield is improved.
2. The electrode heating process capable of blowing the powder into the electric arc furnace adopts an electrode blowing integrated design, the powder blowing adopts the mixed gas of nitrogen and tail gas as a gas source, a large amount of gas is added into an arc area, and the gas provides an electric arc ion source, so that the electric arc intensity is stronger, and the chemical reaction in a molten pool is quicker. Compared with the traditional solid electrode heating process, the electric arc energy utilization rate is higher.
3. The electrode heating process for the electric arc furnace capable of blowing the powder adopts an electrode blowing integrated design, a powder spray gun protective gas channel adopts mixed gas of nitrogen and tail gas as a gas source, a large amount of gas enters a molten pool to drive original oxygen-containing gas, air brought by original melt in the molten pool is separated from the molten pool, and the electric arc furnace is in a reducing atmosphere after repeated circulation, so that the oxidation consumption of the electrode is obviously reduced, the service life of the electrode is prolonged, and the production cost is reduced.
4. The electrode heating process capable of blowing the powder into the electric arc furnace adopts a tail gas recycling and nitrogen composite blowing design, utilizes the tail gas of the electric arc furnace and nitrogen to prepare a mixed blowing system, and replaces partial nitrogen as a powder blowing carrier and graphite electrode protective gas, thereby not only realizing the recycling of the tail gas, but also reducing the use amount of the nitrogen and solving the problem of overhigh nitrogen blowing cost of the electric arc furnace.
5. The electrode heating process capable of blowing the powder into the electric arc furnace adopts a tail gas recycling and nitrogen composite blowing design, the tail gas contains carbon monoxide reducing gas, and the tail gas is recycled into the electric arc furnace, so that the use amount of a reducing agent in the process is saved, and the cost of a reduction process is reduced. The carbon monoxide reducing gas in the tail gas can better protect the electrode and reduce the consumption of the electrode.
6. The invention provides a heating electrode device capable of blowing powder for an electric arc furnace, wherein an electrode blowing integrated device is characterized in that a double-channel powder spray gun is arranged in a central hole of an electrode axis, and powder blown into the central channel is mixed with molten pool melt in a uniform mixing mode under the action of strong electric arc stirring force. Compared with a device which is implemented by separately heating an electrode and blowing powder, the device has better mixing conditions, is more beneficial to mixing and diffusion of the powder in a molten pool, and has better service performance.
7. The invention provides a heating electrode device capable of spraying powder for an electric arc furnace, which is characterized in that a tail gas recycling and nitrogen compound spraying device is characterized in that a bag type dust collector and an induced draft fan for tail gas dust removal, an air pressure station for storing tail gas, a nitrogen pressure regulating station for storing nitrogen, and a mixed gas pressure regulating station for storing mixed gas are arranged outside the electric arc furnace, wherein the mixed gas pressure regulating station is divided into three gas paths which are communicated with a spraying tank for storing powder, a powder distributor for supplying powder to a plurality of electrodes, and a spray gun annular channel for protecting graphite electrodes. Compared with a device for directly discharging tail gas after treatment and injecting nitrogen gas singly, the device has the advantages of better process implementation and is more beneficial to cost reduction and efficiency improvement.
Drawings
FIG. 1 is a flow chart of a process for using a two-electrode DC arc furnace as a smelting reduction furnace according to an embodiment of the present invention.
FIG. 2 is a process flow diagram of an AC ladle refining furnace for refining molten steel according to a second embodiment of the present invention.
Fig. 3 is a schematic structural diagram of electrode blowing integration provided in the embodiment of the present invention.
Figure 4 is a top view of an electrode blowing integration provided by an embodiment of the present invention.
In the figure: 1. an electric arc furnace power supply; 2. a graphite electrode; 3. a powder spray gun; 3-1, a central channel; 3-2, annular channel; 4. an arcing zone; 5. a molten pool; 6. an electric arc furnace; 6-1, an exhaust gas discharge port; 7. a bag type dust collector; 8. an induced draft fan; 9. an air compression station; 10. a nitrogen pressure regulating station; 11. a gas mixing and pressure regulating station; 11-1, a first branch pipeline for gas mixing and supplying; 11-2, a second branch pipeline for gas mixing and supplying; 11-3, a third branch pipeline for gas mixing and supplying; 12. a powder storage bin; 13. a distributor; 14. a blowing tank; 15. a powder dispenser.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, e.g., as being fixed or detachable or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The electric arc furnace has the advantages of high electric arc temperature and easy and accurate control of the temperature in the furnace, and compared with furnace types such as a converter and the like, the electric arc furnace has longer smelting period, larger power consumption and higher smelting cost. The electric arc furnace is heated by a graphite electrode, and the consumption of the graphite electrode also obviously increases the production cost. When the powder is added into the electric arc furnace, the powder and the original melt are difficult to homogenize, the smelting period can be prolonged more, and the power consumption can be further increased. The waste gas generated by smelting is generally discharged after treatment, and the heat contained in the waste gas and the components beneficial to smelting in the gas components are not well utilized. The electrode heating process and the electrode heating device for the electric arc furnace capable of blowing the powder can reduce the consumption of the graphite electrode, recycle and smelt tail gas, shorten the smelting period, save electric energy, reduce cost and improve efficiency.
The embodiment of the invention provides an electrode heating process capable of blowing powder for an electric arc furnace, which comprises an electrode blowing integrated process and a tail gas recycling and nitrogen composite blowing process;
the electrode blowing integrated process is characterized in that a graphite electrode 2 for heating an electric arc furnace 6 is provided with a hole along the axis center, a powder spray gun 3 consisting of an inner layer central channel 3-1 and an outer layer annular channel 3-2 which are coaxially arranged is inserted into a central hole of the graphite electrode 2 to be flush with the front end of the graphite electrode 2, wherein: the powder enters the molten pool 5 from the inner layer central channel 3-1, and the protective gas penetrates into the molten pool 5 from the outer layer annular channel 3-2, so that the powder coming out of the inner layer central channel 3-1 and the protective gas coming out of the outer layer annular channel 3-2 form coaxial power together and enter the molten pool deeply;
the tail gas recycling and nitrogen composite injection process is characterized in that tail gas generated in the smelting process of an electric arc furnace 6 is dedusted by a bag type dust collector 7 and then is sent to an air pressure station 9 by an induced draft fan 8 for storage, and the stored tail gas and nitrogen of a nitrogen pressure regulating station 10 are sent to a mixed gas pressure regulating station 11 for storage according to a certain proportion, so that mixed gas is used for powder blanking of an injection tank 14, powder injection of a powder spray gun 3 and protective gas injection.
The electrode heating device for the electric arc furnace capable of blowing powder is characterized in that the electric arc furnace heating and additive adding are completed by adopting an electrode blowing integrated device, and tail gas generated in the smelting process is recycled by adopting a tail gas recycling and nitrogen composite blowing device.
The electrode blowing integrated device consists of a graphite electrode 2 with an opening in the center of the axis and a powder spray gun 3, wherein the graphite electrode 2 extends into an electric arc furnace 6 and is inserted into a molten pool 5, the powder spray gun 3 is arranged in the center hole of the graphite electrode 3, and the front end part of the powder spray gun 3 is flush with the end part of the graphite electrode 2. The powder spray gun 3 is composed of an inner layer central channel 3-1 and an outer layer annular channel 3-2 which are coaxially arranged, the inner layer central channel 3-1 is a powder blowing channel, and the outer layer annular channel 3-2 is an electrode shielding gas blowing channel.
Tail gas retrieval and utilization and nitrogen gas compound jetting device are become by bag collector 7, draught fan 8, air compression station 9, nitrogen gas pressure regulating station 10, gas mixing pressure regulating station 11 and relevant pipeline connecting piece and valve, 7 entry intercommunication electric arc furnace 6's exhaust gas discharge port 6-1 of bag collector, 8 entries of draught fan are connected through exhaust gas line and valve with 7 exits of bag collector, 9 entries of air compression station communicate with 8 exits of draught fan, nitrogen gas pressure regulating station 10 and air compression station 9 converge for gas mixing pipeline and communicate with gas mixing pressure regulating station 11 through gas conveying pipeline and valve separately.
The outlet of the powder bin 12 is communicated with the powder inlet of the blowing tank 14 through a distributor 13, the powder-carrying air outlet of the blowing tank 14 is connected with the inlet of a central channel 3-1 of a powder spray gun through a powder distributor 15, the pipeline of the outlet of the gas mixing pressure regulating station 11 is divided into three branches, namely a first branch pipeline 11-1 for gas mixing and air supplying, a second branch pipeline 11-2 for gas mixing and air supplying and a third branch pipeline 11-3 for gas mixing and air supplying, the first branch pipeline 11-1 for gas mixing and air supplying is connected with the compressed air inlet of the blowing tank 14, the upper part and the lower part of the blowing tank 14 are provided with compressed air inlets, the powder blowing air flow in the blowing tank is ensured to be uniform, the flowing state is stable, the second branch pipeline 11-2 for gas mixing and air supplying is connected with the inlet of the powder distributor 15, the outlet of the powder distributor 15 is communicated with the inlet of the central channel 3-1 of the powder spray gun through a pipeline, the third branch pipeline 11-3 for gas mixing and supplying is connected with the inlet of the annular channel 3-2 of the powder spray gun.
And valves are arranged on the first branch pipeline for gas mixing and supplying, the second branch pipeline for gas mixing and supplying and the third branch pipeline for gas mixing and supplying, and the opening of the valve is adjusted according to requirements.
When smelting production begins, an electric arc furnace power supply 1 is started, a graphite electrode 2 performs electric arc discharge to form an electric arc operation area 4, a mixed gas supply third branch pipeline 11-3 and a powder spray gun annular channel 3-2 are communicated with electrode protection gas, the protection gas enters an electric arc furnace 6, high-temperature oxidation of the graphite electrode is reduced, consumption of the graphite electrode is reduced, the protection gas forms an electric arc ion gas source in the electric arc discharge area 4, an electrode electric arc discharge effect is enhanced, and the electric arc operation area 4 with higher temperature is formed. The materials in the electric arc furnace 6 are melted by the electric arc operation area 4 at high temperature to form a molten pool 5, the powder distributor 15 is communicated with the central channel 3-1 of the powder injection to perform powder injection according to different smelting stage requirements, the powder can be added according to different process requirements, such as adding reducing agent coke, coal powder and the like when smelting reduction smelting metals, and adding a desulfurizing agent and the like when molten steel is refined. Because the powder is blown and the electric arc is in the same direction, the powder is brought into the deep part of the molten pool by the electric arc, and the powder is rapidly homogenized in the whole molten pool 5 under the action of strong stirring of the electric arc, so that the high-temperature chemical reaction of the powder and the melt is more sufficient. Compared with the conventional graphite electrode and spray gun separate process and device, the method has the advantages of saving the graphite electrode, shortening the smelting period, reducing the electric energy consumption and improving the product quality.
The tail gas generated in the smelting process of the electric arc furnace 6 is discharged through a waste gas discharge port 6-1, dust is removed by a bag type dust collector 7, the gas after dust removal is sent to an air compression station 9 by an induced draft fan 8 for storage, nitrogen stored in a nitrogen pressure regulating station 10 and the tail gas stored in the air compression station 9 are mixed according to a certain proportion and then sent to a mixed gas pressure regulating station 11 according to smelting requirements, the tail gas and the nitrogen are mixed, component adjustment can be carried out according to the working condition of the electric arc furnace, and if the oxygen content in the tail gas is too high, the proportion of the nitrogen can be increased. The mixed gas of the gas mixing and pressure regulating station 11 is sent into the blowing tank 14 through a first branch pipeline 11-1 for gas mixing and supply and is used for discharging of the blowing tank, the mixed gas of the gas mixing and pressure regulating station is sent into a powder distributor 15 through a second branch pipeline 11-2 for gas mixing and supply, the powder distributor 15 is connected with a central channel 3-1 of a powder spray gun and is used for powder blowing, and the mixed gas of the gas mixing and pressure regulating station is sent into an annular channel 3-2 of the powder spray gun through a third branch pipeline 11-3 for gas mixing and supply and is used for graphite electrode protective gas blowing.
The base body of the powder spray gun is made of high-temperature-resistant ceramic materials, such as silicon carbide and silicon nitride, and can bear a high-temperature environment above 1600 ℃.
In this embodiment, a gas component detecting instrument can be added at the outlet of the air compression station 9, and the proportion of the tail gas in the mixed gas can be flexibly adjusted according to the requirements of the smelting gas components of the electric arc furnace.
In conclusion, the electrode heating process and the device for the electric arc furnace capable of blowing the powder, provided by the invention, have the advantages that the electrode spray gun is coaxially and integrally manufactured to carry out electric arc heating and powder blowing, the electric arc smelting intensity is enhanced, the molten pool reactant phase is uniform, the electrode consumption is reduced, and the effective recycling of tail gas is realized.
1. Because the powder spray gun adopts a double-layer structure design, the powder spraying speed of the inner layer central channel of the powder spray gun is enhanced while the outer layer annular channel of the powder spray gun blows electrode protection gas, and thus powder is sent to a deeper area of a molten pool.
2. The powder spray gun and the electrode are positioned on the same axis, and the powder spraying area is superposed with the electrode arc area, so that the powder is uniformly dispersed to the whole molten pool by means of the electric arc stirring force.
3. The outer layer of the powder spray gun can be filled with protective gas, the protective gas is mixed into the whole molten pool by means of electric arc stirring force to drive oxidizing gas to be discharged out of the molten pool and discharged out of the electric arc furnace through a waste gas discharge port to form a protective atmosphere, so that the electrode is protected, and the consumption of the electrode is reduced.
4. Because the tail gas recycling and the nitrogen composite blowing are adopted, the tail gas recycling replaces part of reducing agent, so that the using amount of the reducing agent is reduced, and the using amount of the nitrogen is reduced.
In order that the above-described embodiments of the invention may be better understood, further description thereof may be had with reference to specific examples.
The first embodiment is as follows:
as shown in figure 1, the electrode heating process and the device for the double-top electrode direct current electric arc furnace capable of blowing powder are used for smelting reduction smelting of metallurgical waste residues. As shown in fig. 3 and 4, the graphite electrode 2 is a hollow electrode, the powder spray gun 3 is inserted in the middle, the powder spray gun 3 is divided into an inner layer and an outer layer, wherein the inner layer is a central channel 3-1 for blowing reducing agent coal dust, and the outer layer is an annular channel 3-2 for blowing protective gas nitrogen and assisting in blowing reducing agent coal dust. The double-electrode discharge heats metallurgical waste residues in the electric arc furnace, the high-temperature electric arc melts the solid metallurgical waste residues to form a molten pool, the electric arc forms strong stirring force, the reducing agent coal powder is sprayed to be stirred and dispersed to the whole molten pool along with the electric arc, the high-temperature chemical reaction with the metallurgical waste residues is completed, metal oxides in the metallurgical waste residues are reduced to beneficial metals, and carbon monoxide can be formed in the reducing agent coal powder reduction process, so that a certain amount of carbon monoxide is contained in waste gas.
A tail gas recycling and nitrogen compound injection process and a device are characterized in that waste gas is dedusted by a bag type dust collector 7, the waste gas is introduced into an air compression station 9 for storage by an induced draft fan 8, nitrogen of a nitrogen pressure regulating station 10 and the waste gas of the air compression station 9 are mixed in a proper proportion and then stored in a gas mixing pressure regulating station 11, the mixed gas is divided into three branches from an outlet pipeline of the gas mixing pressure regulating station 11, a first branch pipeline 11-1 of mixed gas supply supplies mixed gas to an injection tank 14 for discharging of the injection tank 14, a second branch pipeline 11-2 of mixed gas supply supplies the mixed gas to a powder distributor 15 and is used for pulverized coal injection of a central channel 3-1 of a powder spray gun 3 through the powder distributor 15, and a third branch pipeline 11-3 of mixed gas supply supplies the mixed gas to an annular channel 3-2 of the powder spray gun 3 for protecting a graphite electrode 2 and reducing graphite consumption.
The invention can realize that the reducing agent coal dust is uniformly dispersed into the molten pool along with the electric arc stirring force, thereby shortening the smelting time, reducing the power consumption and simultaneously improving the product quality; the generated waste gas is recycled through the tail gas recycling and nitrogen composite blowing device, the using amount of a reducing agent is reduced, the graphite electrode 2 is protected, the graphite consumption is reduced, and the production cost is reduced.
Example two:
as shown in figure 2, a heating electrode process and a heating electrode device capable of spraying and blowing a quenching and tempering agent for a double-top electrode ladle refining furnace are used for refining molten steel. As shown in fig. 3 and 4, the graphite electrode 2 is a hollow electrode, the powder spray gun 3 is inserted in the middle, the powder spray gun 3 is divided into an inner layer and an outer layer, wherein the inner layer is a central channel 3-1 for blowing the hardening and tempering agent quicklime, and the outer layer is an annular channel 3-2 for blowing the protective gas nitrogen and assisting in blowing the hardening and tempering agent quicklime. The molten steel in the ladle refining furnace is heated by double-electrode discharge, a strong stirring force is formed by high-temperature electric arc, a conditioner quicklime is sprayed and dispersed to the whole molten pool along with the electric arc stirring, the conditioner quicklime and the molten steel complete high-temperature chemical reaction, sulfur and phosphorus impurities in the molten steel are absorbed into a slag liquid phase, and waste gas is generated in the process of conditioning and refining.
A tail gas recycling and nitrogen compound injection process and a device are characterized in that waste gas is dedusted by a bag type dust collector 7, the waste gas is introduced into an air compression station 9 for storage by an induced draft fan 8, nitrogen of a nitrogen pressure regulating station 10 and the waste gas of the air compression station 9 are mixed in a proper proportion and then stored in a gas mixing pressure regulating station 11, the mixed gas is divided into three branches from an outlet pipeline of the gas mixing pressure regulating station 11, a first branch pipeline 11-1 of mixed gas supply supplies mixed gas to an injection tank 14 for discharging of the injection tank 14, a second branch pipeline 11-2 of mixed gas supply supplies the mixed gas to a powder distributor 15, the mixed gas is distributed to a central channel 3-1 of a powder spray gun 3 for injection of a modifying agent through the powder distributor 15, and a third branch pipeline 11-3 of mixed gas supply supplies the mixed gas to an annular channel 3-2 of the powder spray gun 3 for protecting a graphite electrode 2 so as to reduce graphite consumption.
The adoption of the invention can realize that the hardening and tempering agent quicklime is uniformly dispersed into the molten pool along with the electric arc stirring force, shorten the smelting time, reduce the power consumption and simultaneously improve the product quality; the generated waste gas is recycled through the tail gas recycling and nitrogen composite injection device, the graphite electrode 2 is protected, the graphite consumption is reduced, and the production cost is reduced.
It should be noted here that the nitrogen pressure regulating station 10 in the apparatus may be used for steel making after being replaced with an oxygen pressure regulating station. The inner layer is provided with a central channel 3-1 for blowing the modifier to lightly burn the dolomite, and the outer layer is provided with an annular channel 3-2 for blowing oxygen and assisting in blowing the modifier to lightly burn the dolomite. The electrode discharge heats the scrap steel and the molten iron in the electric arc furnace, the high-temperature electric arc melts the scrap steel and the molten iron together to form a molten pool, the high-temperature electric arc forms strong stirring force, the quenching and tempering agent is sprayed to lightly burn dolomite to be dispersed to the whole molten pool along with the electric arc stirring, the quenching and tempering agent and the molten iron complete high-temperature chemical reaction, excessive carbon in the molten iron is oxidized into gas to complete the decarburization of the molten iron, and other impurities of phosphorus, silicon and the like are absorbed into slag liquid to complete the dephosphorization and desilicification of the molten iron. The smelting time is shortened, the power consumption is reduced, and the product quality is improved; the generated waste gas is recycled, so that the use amount of oxygen is reduced, and the production cost is reduced.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: it is to be understood that modifications may be made to the technical solutions described in the foregoing embodiments, or some or all of the technical features may be equivalently replaced, and the modifications or the replacements may not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (8)
1. A heating electrode device capable of blowing powder for an electric arc furnace is characterized by comprising the electric arc furnace, an electrode blowing integrated device, a tail gas recycling and nitrogen composite blowing device, a powder bin and a blowing tank;
the electrode blowing integrated device consists of a graphite electrode with an opening in the center of the axis and a powder spray gun, the graphite electrode extends into the electric arc furnace and is inserted into a molten pool, the aperture size of the center hole of the graphite electrode is matched with the outer diameter of the powder spray gun, the powder spray gun is arranged in the center hole of the graphite electrode, and the front end part of the powder spray gun is flush with the end part of the graphite electrode; the powder spray gun is composed of an inner layer central channel and an outer layer annular channel which are coaxially arranged, the inner layer central channel is a powder blowing channel, and the outer layer annular channel is an electrode shielding gas blowing channel;
the tail gas recycling and nitrogen compound injection device comprises a bag type dust collector, an induced draft fan, an air compression station, a nitrogen pressure regulating station and a mixed gas pressure regulating station, wherein an inlet of the bag type dust collector is connected with a waste gas discharge port of an electric arc furnace, an outlet of the bag type dust collector is connected with an inlet of the induced draft fan through a pipeline and a valve, an outlet of the induced draft fan is connected with an inlet of the air compression station through a pipeline, and an outlet of the air compression station and an outlet of the nitrogen pressure regulating station are respectively converged into a mixed gas pipeline through respective gas conveying pipelines and valves and are connected with an inlet of the mixed gas pressure regulating station;
an outlet of the powder bin is connected with a powder inlet of the blowing tank, and an air outlet of the blowing tank carrying powder is connected with an inlet of a central channel of the powder spray gun through a powder distributor;
the pipeline at the outlet of the gas mixing and pressure regulating station is divided into three branches, a first branch pipeline for gas mixing and supplying is connected with a compressed air inlet of the blowing tank, the upper part and the lower part of the blowing tank are provided with compressed air inlets, a second branch pipeline for gas mixing and supplying is connected with an inlet of the powder distributor, and a third branch pipeline for gas mixing and supplying is connected with an annular channel inlet of the powder spray gun;
and valves are arranged on the first branch pipeline for gas mixing and supplying, the second branch pipeline for gas mixing and supplying and the third branch pipeline for gas mixing and supplying.
2. The powder-sprayable heating electrode assembly of claim 1, wherein the outlet of the powder hopper is connected to the powder inlet of the spray tank via a distributor.
3. The powder-sprayable powered electrode assembly for an electric arc furnace of claim 1, wherein the base of the powder spray gun is made of a high temperature resistant ceramic material.
4. A heating electrode process adopting the powder blowing agent heating electrode device for the electric arc furnace as claimed in any one of claims 1 to 3, which is characterized by comprising an electrode blowing integrated process and a tail gas recycling and nitrogen compound blowing process;
the electrode blowing integrated process is characterized in that a graphite electrode for heating an electric arc furnace is provided with a hole along the axis center, a powder spray gun composed of an inner layer central channel and an outer layer annular channel which are coaxially arranged is inserted into a graphite electrode center hole to be flush with the front end of the graphite electrode, and the process comprises the following steps: powder enters the molten pool from the inner layer central channel, and protective gas penetrates into the molten pool from the outer layer annular channel, so that the powder coming out of the inner layer central channel and the protective gas coming out of the outer layer annular channel form coaxial power together and go deep into the molten pool;
the tail gas recycling and nitrogen composite blowing process is characterized in that tail gas generated in the smelting process of an electric arc furnace is sent into an air compression station for storage after being dedusted by a bag type dust collector, and the stored tail gas and nitrogen of a nitrogen pressure regulating station are sent into a gas mixing pressure regulating station for storage according to a certain proportion, so that mixed gas is used for blowing tank powder blanking, powder spray gun powder blowing and protective gas blowing.
5. The process for blowing a dust in an electric arc furnace as claimed in claim 4, wherein said dust is added according to different process requirements.
6. The process of claim 4, wherein the maximum particle size of the powder is less than 500 μm.
7. The process of claim 6, wherein the maximum particle size of the powder is less than 200 μm.
8. The electrode-heating process for injectable powders of electric arc furnaces of claim 4 wherein the recycling of the off-gas is combined with the injection of nitrogen, the off-gas being mixed with nitrogen and being adjustable in composition according to the conditions of the electric arc furnace.
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| CN112974738A (en) * | 2021-04-23 | 2021-06-18 | 北京科技大学 | Continuous casting microalloying production method |
| CN115028193B (en) * | 2022-06-15 | 2023-12-05 | 广东先导稀贵金属材料有限公司 | Preparation method of nano indium oxide powder |
| CN115820964A (en) * | 2022-12-08 | 2023-03-21 | 徐州宏阳新材料科技股份有限公司 | Device and method for preparing high-carbon ferrochrome through whole-powder ore smelting |
| CN116103466B (en) * | 2023-02-27 | 2024-01-30 | 北京科技大学 | Top powder spraying high-efficiency steelmaking method and system for large-scale electric arc furnace |
| CN117433288B (en) * | 2023-12-20 | 2024-02-13 | 秦皇岛鸿通机械有限公司 | Molten metal holding furnace capable of reducing generation of oxidizing slag |
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| US5611838A (en) * | 1993-12-10 | 1997-03-18 | Voest-Alpine Industrieanlagenbau Gmbh | Process for producing an iron melt |
| WO2003037038A2 (en) * | 2001-10-26 | 2003-05-01 | Centro Sviluppo Materiali S.P.A. | Electrode, in particular for siderurgical electric arc furnaces and the like, and related operation method |
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| US20170280519A1 (en) * | 2016-03-25 | 2017-09-28 | Air Liquide Industrial U.S. Lp | Inert gas blanketing of electrodes in an electric arc furnace |
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| CN1072459A (en) * | 1991-11-18 | 1993-05-26 | 奥地利钢铁联合企业阿尔帕工业设备制造有限公司 | Electric furnace arrangement for producing steel |
| US5611838A (en) * | 1993-12-10 | 1997-03-18 | Voest-Alpine Industrieanlagenbau Gmbh | Process for producing an iron melt |
| WO2003037038A2 (en) * | 2001-10-26 | 2003-05-01 | Centro Sviluppo Materiali S.P.A. | Electrode, in particular for siderurgical electric arc furnaces and the like, and related operation method |
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