Integral electric arc furnace bottom blowing gas supply element with safety alarm structure

Abstract

The invention discloses an integral electric arc furnace bottom blowing gas supply element with a safety alarm structure. The integral electric arc furnace bottom blowing gas supply element comprises a main body, a gas supply capillary steel pipe, a metal gas chamber, a gas supply gas inlet pipe, a first-stage alarm steel pipe, a first-stage alarm gas inlet pipe, an N-stage alarm steel pipe and an N-stage alarm gas inlet pipe, the metal air chamber is located at the lower end of the main body, and an air supply capillary steel pipe is pre-buried in the center of the interior of the main body and is independently connected with an air supply inlet pipe outside the main body; a first-stage alarm steel pipe and an N-stage alarm steel pipe with closed ends are pre-buried in different safety height line positions in the main body according to the alarm stage number requirement, and the first-stage alarm steel pipe and the N-stage alarm steel pipe are independently connected with a corresponding first-stage alarm air inlet pipe and a corresponding N-stage alarm air inlet pipe respectively and are independent of other air supply channels. And the first-stage alarm air inlet pipe and the N-stage alarm air inlet pipe are arranged outside the main body. By adopting the integral structure, the masonry of the gas supply element is simplified, the service life of the gas supply element is prolonged, and the safety of the gas supply element is improved.

Description

Technical Field

[0001] The invention relates to the technical field of electric arc furnace steelmaking, in particular to an integrated electric arc furnace bottom blowing gas supply element with a safety alarm structure. Background Art

[0002] The electric arc furnace is the core equipment of the short-process steelmaking process. The inert gas Ar (N2) is blown from the bottom of the electric arc furnace to stir the molten steel, which can accelerate the flow of the molten steel, promote chemical reactions, quickly achieve uniform chemical composition and temperature of the molten steel in the molten pool, and reduce smelting costs.

[0003] The bottom blowing gas supply element of the electric arc furnace is a key element to realize the stirring function of the bottom blowing Ar (N2) gas of the electric arc furnace. Blowing inert gas into the molten steel in the furnace can strengthen the stirring of the molten pool, improve the dynamic conditions of the molten pool, and achieve the purpose of reducing power consumption, reducing the consumption of ferroalloys and electrodes, shortening the smelting time, and improving the efficiency of dephosphorization, desulfurization, and decarburization. The bottom blowing gas supply element of the electric arc furnace is in a high-temperature molten steel environment above 1600℃ for a long time. First, during use, the gas at room temperature is continuously blown into the molten steel through the gas supply element. The temperature difference between the upper and lower parts of the air-permeable brick is large. The main body of the refractory material must be able to withstand a large temperature difference and have good thermal shock resistance. Second, the bottom blowing gas is blown into the furnace through the gas supply element, and the gas enters the molten steel, constantly floating and expanding, forming a reflux stirring molten steel within a certain range, which continuously scours and rubs the gas supply element at the bottom of the furnace and the surrounding refractory materials, causing mechanical damage. Therefore, the bottom blowing gas supply element is required to have good thermal shock resistance and scouring and erosion resistance. Third, most electric arc furnace steelmaking operations use the steel-retaining and slag-retaining operation. The furnace bottom condition cannot be observed during the steelmaking process and operation intervals, and it is impossible to perform furnace replenishment and slag splashing operations like the converter. The gas supply components are constantly corroded during the steelmaking process. Without a safety alarm device, the safety of the furnace bottom and gas supply components cannot be guaranteed.

[0004] Traditional assembled electric arc furnace bottom blowing gas supply components, such as Figure 1 As shown: It is assembled by air-permeable core bricks, ramming materials and multiple base bricks. The air-permeable core bricks are relatively small, and the ramming strength and sintering strength of the ramming materials between the air-permeable core bricks and the base bricks restrict the service life of the bottom-blown air-permeable bricks of the electric arc furnace. Secondly, some of the traditional bottom-blowing gas supply components of the electric arc furnace do not have alarm devices, and the residual height cannot be measured. Stopping the furnace too early to replace the gas supply components will cause unnecessary waste; if they are replaced too late, when the bottom-blowing gas supply components are corroded, steel leakage accidents will occur. Some bottom-blowing gas supply components of the electric arc furnace use thermocouples for temperature alarm, but the alarm device is complex to make, and the thermocouple consumption is large and the cost is high. There are also some bottom-blowing gas supply components of the electric arc furnace that are designed with a first-level alarm at a safe height. When the alarm signal is issued, the furnace must be stopped, otherwise it is easy to cause steel leakage accidents, which is not conducive to production scheduling. Summary of the invention

[0005] The object of the present invention is to provide an integral bottom blowing gas supply element for an electric arc furnace with a safety alarm structure, which is easy to lay and install. On the premise of ensuring that gas is blown into the furnace to stir the molten steel, the service life of the gas supply element is increased and its safety is improved, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an integral bottom-blown gas supply element for an electric arc furnace with a safety alarm structure, comprising a main body, on which are provided a gas supply capillary steel pipe, a metal gas chamber, a gas supply inlet pipe, a first-level alarm steel pipe, a first-level alarm inlet pipe, an N-level alarm steel pipe and an N-level alarm inlet pipe; the metal gas chamber is located at the lower end of the main body, and a gas supply capillary steel pipe is pre-buried at the center of the main body, and the gas supply capillary steel pipe is separately connected to the gas supply inlet pipe outside the main body; the main body is pre-buried with a first-level alarm steel pipe and an N-level alarm steel pipe with closed ends at different safety height line positions inside the main body according to the alarm level requirements, the first-level alarm steel pipe and the N-level alarm steel pipe are separately connected to the corresponding first-level alarm inlet pipe and the N-level alarm inlet pipe, respectively, and are independent of other gas supply channels, and the first-level alarm inlet pipe and the N-level alarm inlet pipe are arranged on the outside of the main body.

[0007] Preferably, the main body of the gas supply element is made of high-grade fused large crystal magnesia and high-purity large flake graphite as main raw materials, phenolic resin, phenolic resin combined with asphalt or phenolic resin combined with carbon black as binder, and antioxidants are various composite antioxidants, wherein high-grade fused large crystal has good erosion resistance, and high-purity large flake graphite has good slag corrosion resistance; in terms of mass percentage, it includes 70-94wt% of magnesium oxide (MgO), 2-25wt% of graphite (C), 2-6wt% of phenolic resin binder and 0-5wt% of composite antioxidant. The antioxidant can be metal Al powder, Mg powder, Si powder, Mg-Al alloy powder, non-metallic composite B4C powder, BN powder, AlN powder, SiC powder or Al4C3 powder. Because the environment in which the matrix is ​​used is a harsh environment such as high temperature, repeated scouring and wear, the magnesium-carbon refractory material is required to have excellent oxidation resistance, thermal shock resistance and scouring resistance. Therefore, the selected antioxidant is a composite oxidant, including one or more of metal Al powder, Mg powder, Si powder, Mg-Al alloy powder, non-metallic composite B4C powder, BN powder, AlN powder, SiC powder or Al4C3 powder; among them, the phenolic resin binder in the magnesium-carbon refractory material provides room temperature strength guarantee for the main body of the refractory material, and generally uses thermoplastic or thermosetting phenolic resin. The antioxidant is to improve the oxidation resistance of the magnesium-carbon refractory material. The added antioxidant is oxidized before graphite, and the delayed oxidation of graphite maintains its excellent thermal shock resistance and erosion resistance. The integral structure is not suitable for ordinary friction brick press molding due to its large working end face and volume, and requires isostatic pressing.

[0008] Preferably, the main body shape is one of a cylinder, a truncated cone, a boss, an inclined cone, a cuboid and a multi-sided cone, the main body cross-section is circular with a diameter of 250-600mm, the end face is rectangular or polygonal, the cross-sectional size is ≥220mm*220mm, and the external dimensions are designed according to the use conditions; since the gas supply element supplies gas into the furnace, the gas supply element is subjected to aggravated effects such as stirring and scouring of the molten steel caused by the gas blowing, and since the strength of the gas supply element is higher than the strength of the surrounding furnace bottom ramming material, the larger the size of the gas supply element, the stronger the protection of the furnace bottom, the smaller the erosion rate of the gas supply element, and the longer the service life.

[0009] Preferably, the gas supply capillary steel tube is a steel tube with an inner diameter of 0.5-4 mm, a wall thickness of 1-2 mm, and is made of heat-resistant stainless steel.

[0010] Preferably, the metal air chamber is used to connect and fix the main body with the gas supply capillary steel pipe and alarm steel pipes at various levels. The metal air chamber adopts a circular air chamber or is designed as a square air chamber or a polyhedron air chamber according to a brick-type structure. The wall thickness of the metal air chamber is 8-25mm and the material is carbon steel or stainless steel.

[0011] Preferably, the gas supply inlet pipe is used to supply gas to the gas supply capillary steel pipe and maintain a certain pressure to meet the gas pressure and flow requirements required for blowing. The outer diameter of the gas supply inlet pipe is 10-40mm, the wall thickness is 2-4mm, and the actual size is set according to the size of the bottom blowing gas supply component of the electric arc furnace and the pipeline connection requirements. The material is carbon steel or stainless steel.

[0012] Preferably, the first-level alarm steel pipe is a steel pipe with an inner diameter of 1-4mm, a wall thickness of 1-2mm, and is made of heat-resistant stainless steel. The height of the first-level alarm steel pipe is the minimum safe height of the main body, which is set 250-500mm above the metal gas chamber. The first-level alarm signal is issued, indicating that the bottom blowing gas supply element of the electric arc furnace must be taken offline and shut down.

[0013] Preferably, the first-level alarm air inlet pipe is used to supply air to the first-level alarm steel pipe and maintain a certain pressure, so that when the arc furnace gas supply element is corroded to the alarm position, changes in pressure and flow rate occur, and the corresponding pressure transmitter or flow meter inputs the pressure value or flow rate value into the PLC system. According to the set pressure and flow alarm value parameters, the sound and light alarm (such as a buzzer that emits a sound alarm) set by the PLC control system will sound an alarm; the outer diameter of the first-level alarm air inlet pipe is 6-20mm, and the wall thickness is 2-4mm. The actual size is set according to the size of the arc furnace bottom blowing gas supply element and the pipeline connection requirements.

[0014] Preferably, N in the N-level alarm steel pipe is ≥1, and the alarm levels are divided into 1-5 levels. In most cases, one or two level safety alarms are used, and the alarm position is the safe height of the gas supply component and the height that needs to be warned. Multi-level alarms are generally made according to special requirements of steel mills. The more alarm levels there are, the more alarm gas supply pipelines the steel mill needs to configure. Generally, the length of the second-level alarm steel pipe is 100-200mm longer than that of the first-level alarm steel pipe, that is, the second-level alarm steel pipe is 100-200mm above the safe height. The second-level alarm signal is issued, prompting future smelting operations to pay more attention to the furnace bottom conditions and the safe use of gas supply components. Other three-level, four-level and multi-level alarm steel pipes can be set as needed, and the height can be set according to the safety warning requirements, or it can be set in a step-by-step increase of 100-200mm.

[0015] Preferably, the N-level alarm air inlet pipe is used to supply air to the N-level alarm steel pipe and maintain a certain pressure, so that when the arc furnace gas supply element is corroded to the alarm position, changes in pressure and flow are generated, and the corresponding signal is input into the PLC system, which in turn triggers the sound and light alarm (such as a buzzer that emits a sound alarm) to alarm. The outer diameter of the N-level alarm air inlet pipe is 6-20mm, and the wall thickness is 2-4mm. The actual size is set according to the size of the arc furnace bottom blowing gas supply element and the pipeline connection requirements.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. This integrated arc furnace bottom blowing gas supply element with a safety alarm structure has a gas supply steel pipe and a multi-level alarm steel pipe arranged inside. It uses the change of gas pressure or flow value to alarm. It is simple and easy, and has low cost. The multi-level alarm prompts the operator to arrange the production scheduling reasonably.

[0018] 2. This integral bottom-blowing gas supply component of an electric arc furnace with a safety alarm structure is easy to build and install. On the premise of ensuring that gas is blown into the furnace to stir the molten steel, the service life of the gas supply component is increased and its safety is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the bottom blowing gas supply components of a traditional assembled electric arc furnace;

[0020] Figure 2 is a front view of the overall structure of the first embodiment of the present invention;

[0021] Figure 3 is a top view of the overall structure of the first embodiment of the present invention;

[0022] Figure 4 is a front view of the overall structure of the second embodiment of the present invention;

[0023] Figure 5 is a front view of the overall structure of the third embodiment of the present invention;

[0024] Figure 6 is a top view of the overall structure of the third embodiment of the present invention;

[0025] Figure 7 is a front view of the overall structure of the fourth embodiment of the present invention;

[0026] Figure 8 It is a top view of the overall structure of the fourth embodiment of the present invention.

[0027] In the figure: 1. Main body; 2. Air supply capillary steel pipe; 3. Metal air chamber; 4. Air supply inlet pipe; 5. First-level alarm steel pipe; 6. First-level alarm inlet pipe; 7. Second-level alarm steel pipe; 8. Second-level alarm inlet pipe; 9. Third-level alarm steel pipe; 10. Third-level alarm inlet pipe; 11. First-level alarm steel pipe and air pipe; 12. Support frame; 13. Second-level alarm steel pipe and air pipe. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1:

[0030] See also Figure 2-3In this embodiment, an integrated bottom-blown gas supply element for an electric arc furnace with a safety alarm structure is provided, comprising a main body 1, a gas supply capillary steel pipe 2, a metal gas chamber 3, a gas supply air inlet pipe 4, a first-level alarm steel pipe 5, a first-level alarm air inlet pipe 6, a second-level alarm steel pipe 7 and a second-level alarm air inlet pipe 8; the gas supply capillary steel pipe 2 and the first-level alarm steel pipe 5 and the second-level alarm steel pipe 7 are arranged inside the main body 1 of the refractory material, and the metal gas chamber 3 and the refractory material main body 1 are assembled into one body through the gas supply capillary steel pipe 2 and the first-level alarm steel pipe 5 and the second-level alarm steel pipe 7. The closed end of the alarm steel pipe is placed inside the refractory material main body 1, and the open end is connected to the alarm air inlet pipe. The refractory material body 1 has a truncated cone structure. The diameter of the upper cylinder of the truncated cone is 400mm, and the diameter of the lower cylinder of the truncated cone is 450mm. The lower size is larger, which can prevent the molten steel from directly penetrating downward, thereby improving the safety of the gas supply component. The number of gas supply capillary steel pipes 2 is 8; the outer diameter of the metal gas chamber 3 is 200mm, and the wall thickness is 20mm; the height of the secondary alarm steel pipe 7 is 100mm higher than that of the primary alarm steel pipe 5. The air intake pipe and the alarm height are marked with different colors: the air intake pipe 4 for air supply is sprayed with black paint; the primary alarm air intake pipe 6 is sprayed with red paint, and a red ribbon is sprayed at the corresponding safety height of the refractory material body 1, with a ribbon width of 10mm; the secondary alarm air intake pipe 8 is sprayed with yellow paint, and a yellow ribbon is sprayed at the corresponding safety height of the refractory material body 1, with a ribbon width of 10mm. The color spraying is only used to distinguish the air intake pipe and the alarm position, including but not limited to the three colors described.

[0031] During implementation, the integral arc furnace bottom blowing gas supply element with a two-level alarm structure is directly installed at the bottom of the arc furnace, and the refractory body 1 is compacted with the furnace bottom knotting material. The gas supply inlet pipe 4 and the first-level alarm steel pipe 5 and the second-level alarm steel pipe 7 are respectively connected to the corresponding gas source pipelines at the furnace bottom. During the steelmaking process, inert gas Ar or N2 is blown into the furnace for stirring. When the gas supply element is corroded to the alarm position of the second-level alarm steel pipe 7, the closed end of the alarm steel pipe is melted, the gas flow rate increases sharply, and the flow meter of the valve system detects that the flow rate is greater than the alarm setting value (for example, considering the micro-leakage of the pipeline, the alarm value is set to 10L / min), and the flow signal is input to the PLC system. The PLC control system instructs the sound, light, and electric alarm (this embodiment uses a buzzer for sound alarm) to sound an alarm, prompting the operator to pay attention to the height of the furnace bottom in the later operation and pay attention to the safety of the furnace bottom and the gas supply element. When the gas supply element is corroded to the alarm position of the first-level alarm steel pipe 5, the closed end of the alarm steel pipe is melted, the gas flow rate increases sharply, and the flow meter of the valve system detects that the flow rate is greater than the alarm setting value (for example, considering the micro-leakage of the pipeline, the alarm value is set to 10L / min), and the flow signal is input to the PLC system. The PLC control system instructs the sound, light, and electric alarm (the present embodiment uses a sound alarm, and the alarm is a buzzer) to sound an alarm, prompting the operator to stop the furnace. Generally, there are two operating modes: one is to shut down the gas supply of the gas supply element, repair the furnace bottom, and do not replace the furnace bottom as a whole; the other is to directly stop the furnace and replace the furnace bottom and bottom blowing gas supply element.

[0032] Compared with the prior art, the arc furnace bottom blowing gas supply element with an alarm structure provided in this embodiment has a secondary alarm element inside the base body, which can be used as an early warning prompt, indicating that the gas supply element has been used close to the safe distance, prompting the operator to pay attention to the usable height of the gas supply element, pay attention to the safety of the furnace bottom, reasonably arrange the production rhythm, and prepare in advance for the arc furnace bottom blowing gas supply element to go offline.

[0033] This embodiment is applied to an electric arc furnace of a special steel plant in the west. Its service life exceeds 1,000 furnaces, which is synchronized with the life of the furnace bottom refractory material. When the furnace bottom is replaced, the furnace bottom refractory material and bottom blowing gas supply components can be replaced simultaneously. Compared with the service life of about 400 furnaces of the traditional assembled electric arc furnace gas supply components, the service life of the integral electric arc furnace gas supply components is greatly improved.

[0034] Embodiment 2

[0035] In order to meet the production needs of large and medium-sized electric furnaces, in the second embodiment of the present invention, a first-level alarm steel pipe 5, a second-level alarm steel pipe 7 and a third-level alarm steel pipe 9 are provided. Figure 4As shown, the gas supply element includes a main body 1 of refractory material, a gas supply capillary steel tube 2, a metal gas chamber 3, a gas supply inlet pipe 4, a first-level alarm steel tube 5, a first-level alarm inlet pipe 6, a second-level alarm steel tube 7, a second-level alarm inlet pipe 8, a third-level alarm steel tube 9 and a third-level alarm inlet pipe 10; the gas supply capillary steel tube 2 and the alarm steel pipes, the first-level alarm steel tube 5, the second-level alarm steel tube 7, and the third-level alarm steel tube 9 are arranged inside the main body 1, and the metal gas chamber 3 and the main body 1 are assembled into one through the gas supply capillary steel tube 2 and the first-level alarm steel tube 5, the second-level alarm steel tube 7, and the third-level alarm steel tube 9. The air intake pipe and the alarm height are marked with different colors: the air intake pipe 4 is sprayed with black paint; the first-level air intake alarm steel pipe 6 is sprayed with red paint, and a red ribbon is sprayed at the safety height corresponding to the refractory body 1, with a ribbon width of 10mm; the second-level alarm air intake pipe 8 is sprayed with yellow paint, and a yellow ribbon is sprayed at the safety height corresponding to the refractory body 1, with a ribbon width of 10mm; the third-level alarm air intake pipe 8 is sprayed with green paint, and a green ribbon is sprayed at the safety height corresponding to the refractory body 1, with a ribbon width of 10mm. Color spraying is only used to distinguish the air intake pipe and the alarm position, including but not limited to the three colors described.

[0036] The inner diameter of the first-level alarm steel pipe 5, the second-level alarm steel pipe 7 and the third-level alarm steel pipe 9 is 1-4mm, and the material is heat-resistant stainless steel. The first-level alarm steel pipe 5 is a safety height alarm. The first-level alarm signal is issued, indicating that the bottom blowing gas supply component must be offline and deactivated. The safety height is generally set 250-500mm above the connecting metal gas chamber 3. The length of the second-level alarm steel pipe 7 is generally 100-200mm above the safety height, that is, the length of the alarm steel pipe is 100-200mm longer than the first-level alarm steel pipe 5. The second-level alarm signal is issued, prompting the subsequent smelting operations to pay more attention to the furnace bottom conditions. The length of the third-level alarm steel pipe 9 is 100-200mm longer than the length of the second-level alarm steel pipe 7. The setting of the third-level alarm steel pipe 9 also serves as a measurement of the furnace bottom height and an early warning prompt.

[0037] Similarly, the alarm element adopts an alarm steel pipe, and in order to make the alarm steel pipe play an alarm role, the alarm steel pipe is set to be closed at one end and open at the other end, the closed end is placed in the refractory body 1, and the open end is connected to the alarm gas supply pipe. Gas is introduced into the alarm steel pipe, and the pressure or flow of the gas in the alarm steel pipe is detected by the detection element of the valve station system (not marked in the figure). According to the change of the pressure or flow of the gas in the alarm steel pipe detected, it is judged whether the bottom blowing gas supply element is corroded to the position of the alarm steel pipe. When the flow of gas in the alarm steel pipe is less than the set alarm value (for example, considering the micro leakage of the pipeline, the alarm value is set to 10L / min), it means that the bottom blowing gas supply element of the electric arc furnace has not been corroded to the position of the alarm steel pipe; and when the flow of gas in the alarm steel pipe is greater than the set alarm value (the alarm value is set to 10L / min, and the flow is greater than 10L / min), it means that the bottom blowing gas supply element of the electric arc furnace has been corroded to the position of the alarm steel pipe, which must be paid attention to in operation. When it reaches the alarm position of the first-level alarm steel pipe, the furnace must be stopped as soon as possible to repair the furnace bottom and replace the gas supply element.

[0038] It is worth noting that in order to meet the production needs of large and medium-sized electric arc furnaces, four, five or more levels of alarm steel pipes can be set, but considering the complexity of the gas supply system, it is advisable not to exceed five levels.

[0039] Considering the harsh use conditions of the bottom blowing gas supply element, the base material is required to be not only resistant to high temperature and oxidation, but also have good wear resistance. In order to make the size and structure of the main body of the magnesia carbon refractory material match the surrounding furnace lining bricks, the shape of the main body of the magnesia carbon refractory material in this embodiment is a truncated cone, and the diameter of the safety layer cylinder is larger than that of the upper working layer, which is conducive to preventing the molten steel from directly penetrating downward and avoiding the occurrence of steel leakage accidents.

[0040] Considering that the alarm is judged by detecting the flow of gas in the alarm steel pipe, the air intake pipe that provides gas to the alarm steel pipe needs to have a certain pressure, so as not to cause the alarm to be accurate and timely due to insufficient pressure in the air intake pipe. According to actual production needs, the outer diameter of the air supply air intake pipe is 10-40mm. At the same time, according to the size of the air supply component and the alarm steel pipe and the requirements of pipeline connection, the outer diameter of the alarm air intake pipe is mostly 6-20mm. It can also be designed to the required size according to the size of the valve air supply system pipeline.

[0041] Embodiment 3

[0042] Multi-level alarms require the configuration of multi-level air intake pipes, which will increase the hardware facility cost of the steel plant. In this embodiment, a more reliable embodiment is provided. Figure 5-6As shown, two first-level alarm steel pipes 5 are symmetrically arranged, and the gas supply element includes a main body 1 of refractory material, a gas supply capillary steel pipe 2, a metal gas chamber 3, a gas supply inlet pipe 4, a symmetrically arranged first-level alarm steel pipe 5, a first-level alarm inlet pipe 6, a first-level alarm steel pipe and gas pipe 11 and a support frame 12. The gas supply capillary steel pipe 2 and the first-level alarm steel pipe 5 are arranged inside the main body 1, and the metal gas chamber 3 and the main body 1 are assembled into one body through the gas supply capillary steel pipe 2 and the first-level alarm steel pipe 5. The first-level alarm steel pipe and gas pipe 11 is fixedly installed in the metal gas chamber 3 through the support frame 12.

[0043] The inner diameter of the first-level alarm steel pipe 5 is 1-4mm, and the material is heat-resistant stainless steel. The first-level alarm steel pipe 5 is a safety height alarm. The first-level alarm signal is issued, indicating that the bottom-blowing air supply component must be offline and out of service. The safety height is generally set 250-500mm above the connecting metal air chamber 3. The difference in this case is that the two symmetrically distributed first-level alarm steel pipes 5 can alarm as long as one of them reaches the position where the alarm steel pipe is set. In this way, if there is a difference in the degree of erosion of the air supply component, it can be ensured that the alarm operation can be performed when one end of the air supply component reaches the alarm height. The setting of the position of this alarm steel pipe effectively avoids the untimely alarm caused by different degrees of erosion of the bottom-blowing air supply component.

[0044] Embodiment 4

[0045] In another more reliable embodiment 4, two first-level alarm steel pipes 5 and two second-level alarm steel pipes 7 are symmetrically arranged. Figure 7-8 As shown, the gas supply element includes a main body 1 of refractory material, a gas supply capillary steel pipe 2, a metal gas chamber 3, a gas supply inlet pipe 4, a symmetrically arranged first-level alarm steel pipe 5, a first-level alarm inlet pipe 6, a first-level alarm steel pipe and gas pipe 11, a support frame 12, a symmetrically arranged second-level alarm steel pipe 7, a second-level alarm inlet pipe 8, and a second-level alarm steel pipe and gas pipe 13; the gas supply capillary steel pipe 2 and the first-level alarm steel pipe 5 and the second-level alarm steel pipe 7 are arranged inside the main body 1, and the metal gas chamber 3 and the main body 1 are assembled into one through the gas supply capillary steel pipe 2 and the first-level alarm steel pipe 5 and the second-level alarm steel pipe 7, and the first-level alarm steel pipe and gas pipe 11 and the second-level alarm steel pipe and gas pipe 13 are fixedly installed in the metal gas chamber 3 through the support frame 12.

[0046] The inner diameter of the first-level alarm steel pipe 5 and the second-level alarm steel pipe 7 is 1-4mm, and the material is heat-resistant stainless steel. The first-level alarm steel pipe 5 is a safety height alarm. The first-level alarm signal is issued, indicating that the bottom blowing gas supply component must be offline and deactivated. The safety height is generally set 250-500mm above the connecting metal gas chamber 3. The length of the second-level alarm steel pipe 7 is generally 100-200mm above the safety height, that is, the length of the alarm steel pipe is 100-200mm longer than the first-level alarm steel pipe. The second-level alarm signal is issued, prompting the subsequent smelting operation to pay more attention to the furnace bottom condition.

[0047] The difference in this example is that the two symmetrically distributed alarm steel pipes can alarm as long as one of them reaches the position where the alarm steel pipe is set. In this way, if there are differences in the erosion degree of the air supply component, it can be ensured that the alarm operation can be performed when one end of the air supply component reaches the alarm height. This setting of the alarm steel pipe position effectively avoids the untimely alarm caused by different erosion degrees of the bottom blowing air supply component.

[0048] The results of this implementation show that the bottom-blowing gas supply components of the electric arc furnace made of high-purity large-crystal fused magnesia and high-purity graphite as raw materials and added with composite antioxidants effectively increase the service life of the gas supply components and significantly reduce the erosion rate of the furnace bottom. The safety of the bottom-blowing gas supply components is improved by improving the structure of the gas supply components and adding alarm steel pipes. This implementation has obvious advantages in improving the efficiency of electric arc furnace steelmaking, improving the quality of molten steel and the safety of the steelmaking process.

[0049] When selecting the alarm element, this embodiment also considers the use of thermocouples for temperature alarm, but the alarm device requires an empirical value for the setting of the alarm temperature. Once this set value is wrong, it will affect the accuracy and effectiveness of the alarm. In addition, due to the low strength of the thermocouple and its armor, it is easy to be damaged if it is directly buried; if a blind hole is reserved and the thermocouple is installed later, the accuracy of the reserved blind hole is difficult to guarantee, and the installation is difficult. Due to the high possibility of damage to the thermocouple, the alarm accuracy is reduced. In addition, since the alarm device is destructive, the installation of multi-stage thermocouples has a high economic cost and a large continuous investment.

[0050] After comparison, the present invention chooses to use an alarm steel pipe as the alarm, which has the following advantages: using gas flow alarm, the alarm steel pipe is a heat-resistant stainless steel pipe with one end closed, which is pre-buried during the production process of the main body 1, with small position and height deviations, and the open end is welded or bonded to the alarm air inlet pipe. The air inlet element is connected to the external air supply valve system. Once the air supply element is corroded to the alarm position, the closed end is melted, and the alarm steel pipe begins to ventilate. The flow meter or pressure element of the valve system will show the flow or pressure value change, and an alarm can be issued with high alarm accuracy. The one-time investment cost of the external air supply system that provides gas for the alarm steel pipe is close to that of the temperature alarm system, but the subsequent investment is only a few closed heat-resistant stainless steel pipes, which is much lower than the cost of using thermocouples.

[0051] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0052] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An integrated arc furnace bottom blowing gas supply element with a safety alarm structure, comprising a main body (1), characterized in that: The main body (1) is provided with an air supply capillary steel pipe (2), a metal gas chamber (3), an air supply air intake pipe (4), a first-level alarm steel pipe (5), a first-level alarm air intake pipe (6), an N-level alarm steel pipe and an N-level alarm air intake pipe; the metal gas chamber (3) is located at the lower end of the main body (1), and the air supply capillary steel pipe (2) is pre-buried at the center of the main body (1), and the air supply capillary steel pipe (2) is separately connected to the air supply air intake pipe (4) outside the main body (1); the main body (1) is pre-buried with a first-level alarm steel pipe (5) and an N-level alarm steel pipe with closed ends at different safety height line positions inside the main body (1) according to the alarm level requirements, and the first-level alarm steel pipe (5) and the N-level alarm steel pipe are separately connected to the corresponding first-level alarm air intake pipe (6) and the N-level alarm air intake pipe, respectively, and are independent of other air supply channels, and the first-level alarm air intake pipe (6) and the N-level alarm air intake pipe are arranged outside the main body (1).

2. The integrated bottom blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 1, characterized in that: The main body (1) has an outer shape of a cylinder, a truncated cone, a boss, an inclined cone, a cuboid and a polygonal cone. The main body (1) has a circular cross-section with a diameter of 250-600 mm, an end face of a rectangle or a polygon, and a cross-sectional size of ≥220 mm*220 mm. The outer dimensions are designed according to the conditions of use.

3. The integrated bottom blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 1, characterized in that: The gas supply capillary steel tube (2) is a steel tube with an inner diameter of 0.5-4 mm and a wall thickness of 1-2 mm.

4. The integrated bottom blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 1, characterized in that: The metal air chamber (3) is used to connect and fix the main body (1) with the gas supply capillary steel tube (2) and the alarm steel tubes at various levels. The metal air chamber (3) is a circular air chamber or a square air chamber or a polyhedral air chamber designed according to a brick-type structure. The wall thickness of the metal air chamber (3) is 8-25 mm.

5. The integrated bottom blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 1, characterized in that: The air supply inlet pipe (4) is used to supply air to the air supply capillary steel pipe (2) and maintain a certain pressure to meet the gas pressure and flow requirements required for blowing. The outer diameter of the air supply inlet pipe (4) is 10-40 mm and the wall thickness is 2-4 mm.

6. The integrated bottom blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 1, characterized in that: The first-level alarm steel pipe (5) is a steel pipe with an inner diameter of 1-4 mm and a wall thickness of 1-2 mm. The height of the first-level alarm steel pipe (5) is the minimum safety height of the main body (1) and is arranged 250-500 mm above the metal gas chamber (3).

7. The integrated bottom blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 1, characterized in that: The first-level alarm air inlet pipe (6) is used to supply air to the first-level alarm steel pipe (5). The outer diameter of the first-level alarm air inlet pipe (6) is 6-20 mm, and the wall thickness is 2-4 mm.

8. The integrated bottom blowing gas supply element for an electric arc furnace with a safety alarm structure according to claim 1, characterized in that: In the N-level alarm steel pipe, N≥1, the alarm levels are divided into 1-5 levels, and the alarm position is the safe height and the height requiring warning of the main body (1).

9. The integrated bottom blowing gas supply component of an electric arc furnace with a safety alarm structure according to claim 1, characterized in that: The N-level alarm air inlet pipe is used to supply air to the N-level alarm steel pipe (7). The outer diameter of the N-level alarm air inlet pipe is 6-20 mm, and the wall thickness is 2-4 mm.

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