CN111321272A - Steelmaking device and process for continuously preheating scrap steel - Google Patents
Steelmaking device and process for continuously preheating scrap steel Download PDFInfo
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- CN111321272A CN111321272A CN201811526882.XA CN201811526882A CN111321272A CN 111321272 A CN111321272 A CN 111321272A CN 201811526882 A CN201811526882 A CN 201811526882A CN 111321272 A CN111321272 A CN 111321272A
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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
- C21C5/527—Charging of the electric furnace
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Abstract
The invention provides a steelmaking device and a steelmaking process for continuously preheating scrap steel, wherein the device comprises a scrap steel shaft which is divided into a scrap steel charging shaft and a scrap steel preheating shaft by a second shaft gate arranged at the upper part of the scrap steel shaft, and the top of the scrap steel charging shaft is provided with a first shaft gate for sealing the scrap steel charging shaft; the electric arc furnace comprises a furnace cover and a furnace body which are arranged up and down, wherein the furnace body comprises an upper furnace shell, a molten pool and a lower furnace shell which are arranged up and down in sequence; the upper furnace shell is provided with a multifunctional furnace wall gun; a flue gas outlet arranged on the upper furnace shell of the electric arc furnace is connected with an inlet of the waste steel preheating vertical shaft flue through a flue; and the vibrating feeder is used for feeding the preheated scrap steel into a molten pool of the electric arc furnace. The device and the process provided by the invention are a device and a process for steelmaking by using the scrap steel, which combine scrap steel preheating, electric arc temperature rising, primary energy fluxing, furnace bottom blowing stirring (bottom blowing) and high-efficiency oxygen blowing.
Description
Technical Field
The invention relates to a steelmaking device and a steelmaking process for continuously preheating scrap steel, belonging to the technical field of ferrous metallurgy.
Background
The existing electric furnace process and device for steelmaking by using the scrap steel can be divided into a cold charging mode and a hot charging mode, wherein the cold charging mode is that the scrap steel is directly charged into a furnace for smelting without preheating treatment, and the hot charging mode is that the scrap steel is preheated and then charged into the furnace for smelting. Most traditional electric arc furnace adopt the mode of cold charge to smelt, mainly rely on high temperature electric arc to melt steel scrap and heating molten steel among the smelting process, but electric arc is big to the steel scrap loss of burning, and it is big to melt the noise, and it needs a large amount of oxygen blasts carbon and adds a large amount of slagging scorings to make good foamy slag just can improve electric arc heating efficiency in order to realize submerged arc smelting in the later stage of smelting, produces a large amount of high temperature flue gas direct discharge in the stove. Meanwhile, the furnace cover needs to be unscrewed when scrap steel is added every time, so that environmental pollution and energy loss can be caused. At present, a scrap preheating type electric furnace for a hot charging mode mainly comprises a horizontal continuous preheating Consteel electric furnace and a shaft type electric furnace with a finger valve, wherein both the horizontal continuous preheating Consteel electric furnace and the shaft type electric furnace can realize feeding without opening a cover, and the horizontal molten pool smelting of electric arc heating molten steel is realized. The preheating of the scrap steel mainly utilizes high-temperature flue gas generated in the scrap steel smelting process of the electric furnace, and the high-temperature flue gas passes through the scrap steel to achieve the effect of preheating the scrap steel, so that the utilization rate of energy input into the electric furnace is improved, but the two scrap steel preheating type electric furnaces also have respective advantages and disadvantages. The technology of the Consteel electric furnace equipment is mature, the failure rate is low, the preheating effect is poor because the flue gas only passes through the top of the scrap steel, and the electric consumption of each ton of steel is saved by 30kWh at most. The flue gas of the shaft type electric furnace with the finger valve is diffused from the bottom of the scrap steel material column to the top of the scrap steel material column, so that the convection heat transfer is sufficient, and the ton steel power consumption can be reduced by about 100 kWh.
Therefore, it is an urgent technical problem to be solved in the art to provide a steel-making device and a process for continuously preheating scrap steel.
Disclosure of Invention
To solve the above-mentioned disadvantages and drawbacks, it is an object of the present invention to provide a steelmaking apparatus for continuously preheating scrap.
It is another object of the present invention to provide a process for continuously preheating scrap steel. The process combines scrap steel preheating, electric arc heating, primary energy fluxing, furnace bottom blowing stirring (bottom blowing) and efficient oxygen blowing.
In order to accomplish the above object, in one aspect, the present invention provides a steelmaking apparatus for continuously preheating scrap, wherein the steelmaking apparatus for continuously preheating scrap comprises:
a scrap steel shaft which is divided into a scrap steel charging shaft and a scrap steel preheating shaft by a second shaft gate arranged at the upper part of the scrap steel shaft, and the top of the scrap steel charging shaft is provided with a first shaft gate for sealing the scrap steel charging shaft;
the electric arc furnace comprises a furnace cover and a furnace body which are arranged up and down, wherein the furnace body comprises an upper furnace shell, a molten pool and a lower furnace shell which are arranged up and down in sequence; the upper furnace shell is provided with a multifunctional furnace wall gun;
a flue gas outlet arranged on the upper furnace shell of the electric arc furnace is connected with an inlet of the waste steel preheating vertical shaft flue through a flue;
and the vibrating feeder is used for feeding the preheated scrap steel into a molten pool of the electric arc furnace.
According to the specific embodiment of the invention, in the device, the flue can be a part of the scrap steel preheating vertical shaft, namely the flue and the scrap steel preheating vertical shaft are arranged in a connected mode, of course, the flue and the scrap steel preheating vertical shaft can be arranged in a separated mode, and the purpose of the invention can be achieved only by ensuring.
According to the specific embodiment of the invention, in the device, a plurality of bottom blowing devices are arranged at the bottom of the furnace body and are communicated with the molten pool.
The device provided by the invention is provided with a plurality of furnace bottom blowing devices, so that the melting speed (stirring effect) of the scrap steel can be increased, and the components of the homogenized molten steel can be homogenized; in addition, a person skilled in the art can set the number of bottom-blowing points and the related parameters of each point according to the size of the arc furnace, the molten steel cooling area point and other factors, for example, in the specific embodiment of the present invention, the related parameters of each point are as follows:
flow rate: 0-300L/min, pressure 0.3-0.4MPa, and medium argon or nitrogen.
According to a specific embodiment of the invention, the scrap steel shaft of the device is divided into a scrap steel charging shaft and a scrap steel preheating shaft by a second shaft gate, wherein the scrap steel is preheated only in the scrap steel preheating shaft, and the first shaft gate and the second shaft gate are not opened simultaneously, so as to ensure that the preheated flue gas is extracted into the combustion settling chamber in a relatively stable state all the time.
Specifically, firstly, the dust removal fan works all the time in the whole smelting process. If the scrap steel shaft is only provided with a shaft chamber and a gate, when the gate is opened during the process of adding the scrap steel into the scrap steel shaft (about 3 minutes), a large amount of wild wind can rush from the opened gate, so that the load of a fan is changed, and the temperature of smoke is also fluctuated severely. In the device, the scrap steel shaft is provided with two shaft chambers (one is large and the other is small, wherein the scrap steel preheating shaft is large, and the scrap steel charging shaft is small), and two gates are arranged (the two gates ensure that the scrap steel charging shaft and the scrap steel preheating shaft are both closed spaces), so that the two gates cannot be opened simultaneously in the scrap steel charging process, and the largest fluctuation of the dust removal fan is to increase the smoke volume in the space of the small scrap steel shaft (the scrap steel charging shaft), so that the arrangement mode of the scrap steel shaft in the device can ensure that the preheated smoke is extracted all the time in a relatively stable state and enters the combustion settling chamber (the operation of the fan is facilitated, the smoke temperature is easier to control, and the later-stage smoke treatment is facilitated).
According to the specific embodiment of the invention, the well wall of the scrap steel preheating vertical shaft adopts a structural form that refractory materials (refractory and heat-resistant materials) are attached to the back of a heat-resistant cast iron plate, and can also adopt a water-cooled wall form;
the second shaft gate water-cooling shaft gate plate;
in addition, when the first shaft gate is closed, it is necessary to ensure that it seals the scrap loading shaft.
According to a specific embodiment of the invention, the device further comprises a shaft base for supporting the scrap steel shaft.
In an embodiment of the present invention, the bottom of the scrap preheating shaft may be connected to the surface of the shaft base by welding or bolting.
According to a particular embodiment of the invention, in the device, the shaft base is further provided with a locking device for locking the shaft base.
According to the specific embodiment of the invention, the device also comprises a pusher which is positioned on the base of the vertical shaft and used for pushing the preheated scrap steel to the hopper of the vibrating feeder, and then the preheated scrap steel is sent to the molten pool of the electric arc furnace by the vibrating feeder.
According to a particular embodiment of the invention, the installation further comprises a shaft moving device connected to the shaft base for pulling the shaft base to separate the scrap steel shaft from the body of the electric arc furnace.
According to a particular embodiment of the invention, in the installation described, the scrap preheating shaft and the shaft base are located on one side of the electric arc furnace and can be separated from the electric arc furnace without affecting the operations of tapping, lower shell lifting replacement, etc. of the electric arc furnace.
According to the specific embodiment of the invention, the device also comprises a combustion settling chamber, wherein a flue gas outlet of the scrap steel preheating vertical shaft is connected with an inlet of the combustion settling chamber through a pipeline;
preferably, the inlet and/or the outlet of the combustion settling chamber are/is provided with a plurality of gas burners.
In a more preferred embodiment of the invention, the number of gas burners is 3 to 5, and the capacity of each gas burner is 1.5 to 3 MW.
According to a particular embodiment of the invention, the apparatus further comprises a quench tower, the gas outlet of the combustion settling chamber being connected via a line to the inlet of the quench tower.
According to a particular embodiment of the invention, in said apparatus, a temperature measuring device is provided at the inlet of the combustion settling chamber.
The temperature measuring device is arranged at the inlet of the combustion settling chamber and close to the combustion settling chamber and used for judging the temperature of the flue gas entering the combustion settling chamber, and if the temperature of the flue gas is lower than 800 ℃, a gas burner is required to be started to heat the flue gas entering the combustion settling chamber.
According to a specific embodiment of the invention, in the device, the furnace cover is provided with an electrode hole, an electrode is arranged in the electrode hole, the upper end of the electrode is positioned outside the electric arc furnace, and the lower end of the electrode is positioned in the electric arc furnace and extends into the molten pool;
preferably, the upper end of the electrode is connected with a conductive cross arm.
Wherein the electrode can move up and down along with the conductive cross arm.
According to the specific embodiment of the invention, the steelmaking device for continuously preheating the scrap steel is also provided with a sealing cover used for sealing the vibrating feeder in the flue of the scrap steel preheating vertical shaft.
In the specific implementation mode of the invention, the sealing cover is fixed on the scrap steel preheating vertical shaft and the vertical shaft base through bolts so as to seal the vibrating feeder in the flue of the scrap steel preheating vertical shaft; the sealing cover is only opened in the direction of a flue gas outlet of the furnace shell on the electric arc furnace, so that high-temperature flue gas in the electric arc furnace can smoothly enter the scrap steel preheating vertical shaft.
In addition, the sealing cover can be a composite structure formed by adhering refractory materials (conventional refractory materials in the field) to a steel plate, and can also be a water-cooling sealing cover.
On the other hand, the invention also provides a steelmaking process for continuously preheating the scrap steel, wherein the steelmaking process for continuously preheating the scrap steel adopts the steelmaking device for continuously preheating the scrap steel, and the steelmaking process for continuously preheating the scrap steel comprises the following steps:
(1) electrifying and melting: electrifying the electric arc furnace to melt furnace burden in the molten pool of the electric arc furnace;
(2) preheating and feeding scrap steel: introducing flue gas generated in the melting process into a scrap steel preheating vertical shaft for preheating scrap steel, and adding the preheated scrap steel into a molten pool;
(3) oxygen blowing and carbon spraying and secondary combustion: blowing oxygen into the molten pool according to a set flow and a certain proportion, and spraying carbon into the slag; secondary combustion of CO generated in the oxygen blowing and carbon spraying processes is carried out to obtain high-temperature flue gas, and the high-temperature flue gas is introduced into a scrap preheating vertical shaft to preheat scrap;
(4) deslagging;
(5) and (6) tapping.
According to the specific embodiment of the invention, the process further comprises operations of scrap steel pretreatment (classification, crushing, processing, screening), batching, transferring and the like, which are all conventional operations in the field, and a person skilled in the art can treat the scrap steel according to the existing technical means as long as the purpose of the invention can be achieved.
According to a specific embodiment of the invention, the preheating of the scrap, the melting of the electrodes, and the blowing of oxygen and carbon may be carried out simultaneously in the process.
According to the specific embodiment of the invention, the process step (1) further comprises the step of blowing oxygen into the molten bath according to a certain proportion to accelerate the melting of the charge materials when the charge materials are melted.
According to a specific embodiment of the present invention, the process further comprises blowing a bottom-blowing gas into the molten bath by a bottom-blowing device in steps (1) to (3).
According to the specific embodiment of the invention, the scrap steel preheating and feeding in the step (2) of the process specifically comprises the following steps:
pushing the preheated scrap steel into a hopper of a vibrating feeder in batches by using a pusher, and then feeding the preheated scrap steel into a molten pool of an electric arc furnace by the vibrating feeder; when the preheated scrap steel is pushed for a preset number of times, the scrap steel preheating shaft can leave a certain space, at the moment, a second shaft gate is opened to enable the scrap steel in the scrap steel charging shaft to fall into the scrap steel preheating shaft, and the second shaft gate is closed and preheating is continued; and opening the first shaft gate, closing the first shaft gate after continuously adding the scrap steel into the scrap steel charging shaft, and repeating the operations of adding the scrap steel into the scrap steel preheating shaft and the scrap steel charging shaft and preheating the scrap steel.
In the steel-making process for continuously preheating the scrap steel, the frequency of adding the scrap steel into the scrap steel charging vertical shaft can be reasonably controlled according to the field operation requirement (namely, feeding is discontinuously carried out at a certain frequency); however, the method for adding the steel scrap into the steel scrap charging vertical shaft is not particularly required, and in a specific embodiment of the invention, the steel scrap charging vertical shaft can be charged in a skew bridge trolley manner as long as the charging frequency is met.
According to the specific embodiment of the invention, the process also comprises the operation of introducing the preheated flue gas into the combustion settling chamber and treating the flue gas at the temperature of more than 800 ℃, and then introducing the treated gas into the quenching tower and cooling the gas to the temperature of less than 200 ℃. Wherein, the gas after the treatment of quench tower can be sent to flue gas dust pelletizing system and continue to handle.
According to the specific embodiment of the invention, in the process, the steel scrap smelting process adopts steel and slag retention operation, and the steel scrap is heated and melted in an energy supply mode combining electric arc heating, oxygen blowing and carbon spraying, oxygen and gas combustion fluxing, meanwhile, high-temperature flue gas generated in the steel scrap smelting process is led into a steel scrap charging vertical shaft in the whole process and preheats the steel scrap in a vertical shaft channel, the preheated steel scrap is pushed into a furnace molten pool for melting in batches by a steel pusher, and the preheating of the steel scrap is preheated in a mode of approximately continuous certain period; and then, a multifunctional furnace wall gun or an embedded oxygen gun is used for blowing oxygen efficiently and spraying carbon powder to make foam slag so as to realize submerged arc smelting, meanwhile, the molten steel can be continuously heated to the qualified tapping temperature by electric arc heating, the molten steel is heated by electric arc all the time in the whole smelting process, waste steel is melted in high-temperature molten steel, chemical reaction also occurs in a metal liquid phase, and the electric arc completely works under the condition of a flat bath.
And then introducing the preheated flue gas into a combustion settling chamber and treating the flue gas at the temperature of over 800 ℃, wherein the dioxin in the waste gas can be ensured to be fully cracked, and then introducing the treated gas into a quenching tower and cooling the gas to the temperature of below 200 ℃, so that the dioxin can be prevented from being generated again, and the gas reaches the environmental protection emission standard specified by the state.
According to the specific embodiment of the invention, in the process step (1), the furnace burden is retained steel, and when the retained steel exists in the electric arc furnace, the steelmaking process for continuously preheating the scrap steel can be operated according to the steps (1) to (5);
if the first smelting of the new furnace lining is carried out, namely no steel is left in the electric arc furnace, the steel is required to be left in the electric arc furnace, and the method specifically comprises the following steps:
firstly, lifting a conductive cross arm to lift an electrode into a furnace cover of an electric furnace, unscrewing the furnace cover and the electrode together through a rotating mechanism, adding a certain amount of scrap steel (the amount meeting the requirement of steel remaining in a molten pool) into the molten pool by using a scrap steel basket, and then screwing back the furnace cover and the electrode; and then electrifying to melt the scrap steel to obtain the retained steel.
According to a particular embodiment of the invention, in the process described, all the scrap is preheated after the second pass and then fed to the bath for melting, the scrap preheating being carried out in a cyclic, approximately continuous manner.
According to the specific embodiment of the invention, in the process, the smoke dust in the whole steel making process is extracted in a relatively stable state, the extracted smoke dust is adsorbed by the scrap steel (namely, the smoke gas is used for preheating the scrap steel), and no large amount of scrap steel is added in a mode of unscrewing the furnace cover of the electric furnace (except for first feeding), so that the smoke dust emission in the steel making process is reduced, and the power of a dust removal fan is further reduced.
Secondly, in the process, steel retention and slag retention are adopted, energy is transferred by the retained steel to accelerate the melting of scrap steel, electric arc only heats the molten steel, flat molten pool smelting is realized, electric arc heating is more stable, noise is lower, and impact on a power grid is small; specifically, in the application, the charging mode and the scrap melting mode ensure flat bath smelting: firstly, a certain amount of molten steel (steel remaining amount) is stored in a furnace body before smelting begins; and secondly, in a feeding mode, scrap steel in the scrap steel shaft is fed into a molten pool in batches through a steel pusher and a vibrating feeder in the whole smelting process, molten steel is heated by an electrode arc, the molten steel transfers heat to the scrap steel and melts the scrap steel, the feeding amount of each batch is matched with the heating power of the electrode arc, the next feeding is ensured, the last fed scrap steel is changed into a liquid state, a large amount of unmelted scrap steel is not accumulated in the molten pool, the electrode arc always heats the molten steel, and the flat molten pool smelting is realized (the scrap steel is melted by the conventional electric arc).
In addition, the process provided by the invention adopts an energy supply mode combining the heating of an electrified arc, the carbon blowing and spraying of oxygen, the combustion and the fluxing of oxygen and fuel gas to heat and melt the scrap steel at the same time, and a bottom blowing device at the bottom of the furnace is arranged to increase the melting speed of the scrap steel and homogenize the components of molten steel; and the secondary combustion of the flue gas, the preheating of the waste steel by the flue gas and the high-temperature flue gas and the cracking of dioxin are combined, and the flue gas is rapidly cooled by a quench tower to avoid the secondary synthesis of the dioxin.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic structural view of the steel-making apparatus for continuously preheating scrap according to embodiment 1 of the present invention.
The main reference numbers illustrate:
1. a furnace body; 2. a lower furnace shell; 3. a multifunctional furnace wall gun; 4. a furnace bottom blowing device; 5. an electrode; 6. a molten pool; 7. a furnace cover; 8. a conductive cross arm; 9. a vibrating feeder; 10. a locking device; 11. a sealing cover; 12. a shaft base; 13. a shaft mobile device; 14. a gas burner; 15. a combustion settling chamber; 16. a quench tower; 17. a temperature measuring device; 18. a pusher; 19. a second shaft gate; 20. a first shaft gate; 21. a scrap steel charging shaft; 22. a scrap steel preheating vertical shaft; 23, an upper furnace shell.
Detailed Description
In order to clearly understand the technical features, objects and advantages of the present invention, the following detailed description of the technical solutions of the present invention will be made with reference to the following specific examples, which should not be construed as limiting the implementable scope of the present invention.
Example 1
The present embodiment provides a steelmaking apparatus for continuously preheating scrap, which is schematically shown in fig. 1, and as can be seen from fig. 1, the steelmaking apparatus includes:
a scrap steel shaft partitioned into a scrap steel charging shaft 21 and a scrap steel preheating shaft 22 by a second shaft gate 19 provided at an upper portion thereof, and a first shaft gate 20 provided at a top of the scrap steel charging shaft 21 to seal it;
a shaft base 12 for supporting a scrap steel shaft; the shaft base 12 is also provided with a locking device 10 for locking the shaft base 12;
a shaft moving device 13, the shaft moving device 13 being connected to the shaft base 12 for pulling the shaft base 12 to separate the scrap steel shaft from the body 1 of the electric arc furnace;
the electric arc furnace comprises a furnace cover 7 and a furnace body 1 which are arranged up and down, wherein the furnace body 1 comprises an upper furnace shell 23, a molten pool 6 and a lower furnace shell 2 which are arranged up and down in sequence; the upper furnace shell 23 is provided with a multifunctional furnace wall gun 3; the upper furnace shell 23 is provided with a flue gas outlet, and the lower furnace shell is provided with a slag outlet and a steel outlet;
a flue gas outlet arranged on the upper furnace shell 23 of the electric arc furnace is connected with an inlet of a flue of the scrap steel preheating vertical shaft 22 through a flue;
the bottom of the furnace body 1 is provided with a plurality of furnace bottom blowing devices 4, and the furnace bottom blowing devices 4 are communicated with the molten pool 6;
the furnace cover 7 is provided with an electrode hole, the electrode 5 is arranged in the electrode hole, the upper end of the electrode 5 is positioned outside the electric arc furnace, and the lower end of the electrode 5 is positioned in the electric arc furnace and extends into the molten pool 6;
the upper end of the electrode 5 is connected with a conductive cross arm 8, and the electrode 5 can move up and down along with the conductive cross arm 8;
a vibrating feeder 9 for feeding the preheated scrap steel into the molten bath 6 of the electric arc furnace;
in this embodiment, the steelmaking device for continuously preheating the scrap steel is further provided with a sealing cover 11, and the sealing cover 11 is fixed on the scrap steel preheating shaft 22 and the shaft base 12 by bolts so as to seal the vibrating feeder 9 in the flue of the scrap steel preheating shaft 22; the sealing cover 11 is only opened in the direction of a flue gas outlet of an upper furnace shell 23 of the electric arc furnace, so that high-temperature flue gas in the electric arc furnace can smoothly enter a scrap steel preheating vertical shaft 22;
the sealing cover 11 is a composite structure formed by attaching refractory materials (conventional refractory materials in the field) to a steel plate, and can also adopt a water-cooling type sealing cover;
the pusher 18 is positioned on the vertical shaft base 12 and used for pushing the preheated scrap steel to the hopper of the vibrating feeder 9, and then the preheated scrap steel is sent to the melting bath 6 of the electric arc furnace by the vibrating feeder 9;
a combustion settling chamber 15, wherein the flue gas outlet of the scrap steel preheating vertical shaft 22 is connected with the inlet of the combustion settling chamber 15 through a pipeline;
a plurality of gas burners 14 are arranged at a flue gas inlet of the combustion settling chamber 15; a temperature measuring device 17 is also arranged at the flue gas inlet of the combustion settling chamber 15;
a quenching tower 16, wherein the gas outlet of the combustion settling chamber 15 is connected with the inlet of the quenching tower 16 through a pipeline, and the gas outlet of the quenching tower 16 is connected with the flue gas dust removal system through a pipeline.
Example 2
The embodiment provides a steelmaking process for continuously preheating scrap steel, which is realized by adopting the steelmaking device for continuously preheating scrap steel provided by the embodiment 1, wherein the steelmaking process for continuously preheating scrap steel comprises the following specific steps:
step (1): opening the furnace cover for charging for the first time.
The step is mainly suitable for the first smelting of a new furnace lining and is used for generating steel left in the furnace, and when the steel left in the furnace is existed, the step (2) is started. The step (1) specifically comprises the following steps: the electrode is lifted into the lid of the electric furnace by first raising the conductive cross arm, the lid and the electrode are unscrewed together by a rotating mechanism (not shown in fig. 1), a certain amount of scrap (the amount required to satisfy the steel retention in the molten pool) is added to the molten pool by a scrap basket, and then the lid and the electrode are rotated back.
Step (2): electrode melting and oxygen combustion fluxing.
After the step (1) is completed, the conductive cross arm drives the electrode to descend and the scrap steel to strike an arc, the scrap steel is melted by using the heat energy of the arc, and the conductive cross arm is controlled to ascend and descend by an electrode adjusting system (not shown in figure 1) so as to control the arc length to melt furnace burden; oxygen combustion fluxing and electrode melting can be carried out simultaneously, and a multifunctional furnace wall gun arranged on the furnace wall can be used in the furnace to blow oxygen into the molten pool according to a certain proportion, so that the fluxing function of a burner is exerted, and the operation of melting the furnace charge is accelerated.
And (3): initial charging in a steel scrap shaft.
This step (3) may be carried out simultaneously with the step (2). The scrap steel is added into the scrap steel vertical shaft through a scrap steel skew bridge trolley (not shown in figure 1; the feeding form is not restricted in the patent, and the feeding period is met).
And (4): leaving a molten steel pool to form.
In the process of executing the steps (2) to (3), the scrap steel is continuously melted, and the step (6) can be carried out after the steel-remaining molten pool is formed.
And (5): and preheating the scrap steel.
And (4) in the process of completing the steps (2) to (4), introducing high-temperature flue gas generated in the electrifying and melting process into the scrap steel preheating vertical shaft to preheat the scrap steel in the scrap steel preheating vertical shaft.
And (6): and (3) a circulation mode feeding mode in the scrap steel shaft.
Pushing the preheated scrap steel in the step (5) into a hopper of a vibrating feeder in batches by using a pusher, and then conveying the preheated scrap steel into a molten pool by the vibrating feeder; when the material pushing reaches a preset number of times, a certain space is left in the scrap steel preheating shaft, the second shaft gate is opened at the moment so that the scrap steel in the scrap steel charging shaft falls into the scrap steel preheating shaft, the second shaft gate is closed to preheat the scrap steel, then the first shaft gate is opened, the scrap steel is added into the scrap steel charging shaft by using an inclined bridge trolley, the first shaft gate is closed after the charging is finished, and the next cyclic charging period is repeated;
the circulating steps are as follows: preheating the steel scrap in the steel scrap preheating shaft, pushing the preheated steel scrap in the steel scrap preheating shaft in batches (making up the space for accommodating the steel scrap in the steel scrap charging shaft), opening a second shaft gate, blanking, closing the second shaft gate, opening a first shaft gate, feeding the steel scrap charging shaft, and closing the first shaft gate.
And (7): blowing oxygen and spraying carbon.
When the molten pool in the furnace body is formed, the oxygen-blowing and carbon-spraying operations can be synchronously carried out, the multifunctional furnace wall gun arranged on the furnace wall is used for blowing oxygen and spraying carbon to the molten pool according to the set flow and proportion, the oxygen is sprayed into the metal molten pool by adjusting the angle of the spray gun of the multifunctional furnace wall gun, and the carbon powder is sprayed into the slag, so that the reasonable thickness of the foamed slag is formed, and the temperature rising speed of the molten steel is ensured.
And (8): secondary combustion of flue gas.
In the smelting process, a large amount of CO gas (primary combustion) is generated in the carbon-spraying oxygen-blowing process, and before the gas enters the scrap preheating shaft, new air is supplemented (the new air refers to the air supplemented from the gap between the scrap preheating shaft 22 and the furnace body 1, wherein a certain gap is reserved between the scrap preheating shaft 22 and the furnace body 1 of the device in the design process), and the temperature of the flue gas is far higher than 650 ℃, so that secondary combustion of the CO gas is generated, the temperature of the flue gas is further increased through heat release of the secondary combustion, the flue gas with the increased temperature is pumped into the scrap preheating shaft, the scrap in the scrap preheating shaft is continuously preheated, and the energy consumption of the whole smelting is reduced.
And (9): and (4) bottom blowing.
In the step 2- (8), a bottom blowing device arranged at the bottom of the furnace can be opened to blow bottom blowing gas into the molten pool in stages so as to stir the molten steel, increase the heat transfer efficiency, accelerate the melting of the scrap steel and play a role in homogenizing the components of the molten steel.
Step (10): and (6) deslagging.
From step (7), slag is continuously produced in the furnace, and after accumulating to a certain extent, the slag can be continuously discharged through a slag outlet provided in the upper shell. Before slag discharging, the vertical shaft moving equipment is used for separating the scrap steel vertical shaft from the furnace body, and the tilting of the furnace body during slag discharging can not be influenced at the moment.
Step (11): and (6) tapping.
After the step (9) is completed, when the temperature and the content of the components in the molten bath in the furnace reach the set target, the molten steel can be discharged through a steel outlet arranged on the upper furnace shell. Before tapping, the shaft moving equipment is used for separating the scrap steel shaft from the furnace body, and the tilting of the furnace body during tapping can not be influenced at the moment.
Claims (10)
1. A steelmaking apparatus for continuously preheating scrap, comprising:
a scrap steel shaft which is partitioned into a scrap steel charging shaft (21) and a scrap steel preheating shaft (22) by a second shaft gate (19) provided at an upper portion thereof, and a first shaft gate (20) provided at a top of the scrap steel charging shaft (21) for sealing the same;
the electric arc furnace comprises a furnace cover (7) and a furnace body (1) which are arranged up and down, wherein the furnace body (1) comprises an upper furnace shell (23), a molten pool (6) and a lower furnace shell (2) which are arranged up and down in sequence; the upper furnace shell (23) is provided with a multifunctional furnace wall gun (3);
a flue gas outlet arranged on an upper furnace shell (23) of the electric arc furnace is connected with an inlet of a flue of the scrap steel preheating vertical shaft (22) through a flue;
a vibrating feeder (9) for feeding the preheated scrap steel into a molten pool (6) of the electric arc furnace;
preferably, a plurality of bottom blowing devices (4) are arranged at the bottom of the furnace body (1), and the bottom blowing devices (4) are communicated with the molten pool (6);
preferably, the steelmaking device for continuously preheating the scrap steel is also provided with a sealing cover (11) used for sealing the vibrating feeder (9) in a flue of the scrap steel preheating vertical shaft (22).
2. The apparatus according to claim 1, characterized in that it further comprises a shaft base (12) for supporting a scrap steel shaft.
3. Device according to claim 2, characterized in that the shaft bedplate (12) is further provided with locking means (10) for locking the shaft bedplate (12).
4. A device according to any one of claims 1-3, characterized in that the device further comprises a pusher (18) on the shaft base (12) for pushing the preheated scrap into the hopper of the vibrating feeder (9) and from there into the bath (6) of the electric arc furnace.
5. The apparatus according to any of claims 1 to 3, characterized in that the apparatus further comprises a shaft moving device (13), which shaft moving device (13) is connected to the shaft base (12) for pulling the shaft base (12) to separate the scrap shaft from the furnace body (1) of the electric arc furnace.
6. The plant according to any of the claims from 1 to 3, characterized in that it further comprises a combustion settling chamber (15), the fume outlet of said scrap preheating shaft (22) being connected via a pipe to the inlet of the combustion settling chamber (15);
preferably, the inlet and/or the outlet of the combustion settling chamber (15) is/are provided with a plurality of gas burners (14).
7. An apparatus according to claim 6, characterized in that the apparatus further comprises a quench tower (16), and that the gas outlet of the combustion settling chamber (15) is connected to the inlet of the quench tower (16) via a line.
8. The device according to claim 6, characterized in that the inlet of the combustion settling chamber (15) is provided with a temperature measuring device (17).
9. An apparatus according to any one of claims 1-3, characterized in that the furnace lid (7) is provided with an electrode hole, in which the electrode (5) is mounted, the upper end of the electrode (5) being located outside the electric arc furnace and the lower end of the electrode (5) being located inside the electric arc furnace and projecting into the molten bath (6);
preferably, the upper end of the electrode (5) is connected with a conductive cross arm (8).
10. A steel-making process for continuously preheating scrap steel, characterized in that the steel-making process for continuously preheating scrap steel employs the steel-making apparatus for continuously preheating scrap steel according to any one of claims 1 to 9, and the steel-making process for continuously preheating scrap steel comprises the steps of:
(1) electrifying and melting: electrifying the electric arc furnace to melt furnace burden in a molten pool (6) of the electric arc furnace;
(2) preheating and feeding scrap steel: introducing flue gas generated in the melting process into a scrap steel preheating vertical shaft (22) for preheating scrap steel, and adding the preheated scrap steel into a molten pool (6);
(3) oxygen blowing and carbon spraying and secondary combustion: blowing oxygen into the molten pool (6) according to a set flow and a certain proportion, and spraying carbon into the slag; CO generated in the oxygen blowing and carbon spraying processes is combusted secondarily to obtain high-temperature flue gas, and the high-temperature flue gas is introduced into a scrap preheating vertical shaft (22) to preheat scrap;
(4) deslagging;
(5) tapping;
preferably, the process step (1) further comprises the operation of blowing oxygen into the molten pool (6) according to a certain proportion to accelerate the melting of the charge when melting the charge;
also preferably, the process further comprises the operation of blowing bottom-blowing gas into the molten bath (6) by a bottom-blowing device in steps (1) to (3);
still preferably, the scrap steel preheating and feeding in the step (2) specifically comprises the following steps:
pushing the preheated scrap steel into a hopper of a vibrating feeder (9) by using a pusher (18) in batches, and then sending the preheated scrap steel into a molten pool (6) of an electric arc furnace by the vibrating feeder (9); when the preheated scrap steel is pushed for a preset number of times, the scrap steel preheating vertical shaft (22) can leave a certain space, at the moment, a second vertical shaft gate (19) is opened to enable the scrap steel in the scrap steel charging vertical shaft (21) to fall into the scrap steel preheating vertical shaft (22), and the second vertical shaft gate (19) is closed and preheating is continued; opening the first shaft gate (20), continuously adding the scrap steel into the scrap steel charging shaft (21), closing the first shaft gate (20), and repeating the operations of adding the scrap steel into the scrap steel preheating shaft (22) and the scrap steel charging shaft (21) and preheating the scrap steel;
preferably, the process also comprises the operation of introducing the preheated flue gas into the combustion settling chamber (15) and treating the flue gas at a temperature above 800 ℃, and then introducing the treated flue gas into the quenching tower (16) and cooling the treated flue gas to a temperature below 200 ℃.
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| CN201811526882.XA CN111321272A (en) | 2018-12-13 | 2018-12-13 | Steelmaking device and process for continuously preheating scrap steel |
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| CN201811526882.XA CN111321272A (en) | 2018-12-13 | 2018-12-13 | Steelmaking device and process for continuously preheating scrap steel |
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| CN112378269A (en) * | 2020-11-13 | 2021-02-19 | 圣力(清远)钢制品有限公司 | Electric furnace system |
| CN112648618A (en) * | 2020-10-28 | 2021-04-13 | 杭州正隆环保科技有限公司 | Material feeder |
| CN112902681A (en) * | 2021-02-05 | 2021-06-04 | 湖南省东安湘江焊材有限公司 | Waste gas heat recovery device for flux smelting |
| CN113203284A (en) * | 2021-04-15 | 2021-08-03 | 江苏迅隆铝业有限公司 | Aluminum alloy continuous melting furnace for regenerating resin sand by using waste heat |
| CN113957201A (en) * | 2021-11-15 | 2022-01-21 | 中冶京诚工程技术有限公司 | Method for preheating magnetic suspension scrap steel and electric arc furnace steelmaking device capable of preheating magnetic suspension scrap steel |
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| CN113203284A (en) * | 2021-04-15 | 2021-08-03 | 江苏迅隆铝业有限公司 | Aluminum alloy continuous melting furnace for regenerating resin sand by using waste heat |
| CN113957201A (en) * | 2021-11-15 | 2022-01-21 | 中冶京诚工程技术有限公司 | Method for preheating magnetic suspension scrap steel and electric arc furnace steelmaking device capable of preheating magnetic suspension scrap steel |
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| CN114774625B (en) * | 2022-05-10 | 2024-04-09 | 湖南华菱涟源钢铁有限公司 | Method for preheating and melting scrap steel step by step |
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