CN110388830B - Scrap steel preheating device, arc melting equipment and preheating method - Google Patents

Abstract

The invention provides a scrap steel preheating device, arc melting equipment and a preheating method. The scrap steel preheating device includes: a shaft, the upper end is a feed port, and the lower end side wall of the shaft is provided with a discharge port; an unloader is provided on The unloader is in the shaft and can move in the vertical direction relative to the shaft. The unloader has an upper surface inclined toward the discharge port; the material transport trolley can vibrate and transport materials, and the inlet end of the material transport trolley is connected to the discharge port; the guide The roller is arranged at the discharge port and is located above the entrance end of the material transport trolley. The guide roller can control the opening of the discharge port. The beneficial effect of the present invention is that the unloader can be adjusted in the height direction. By adjusting the height of the unloader and the position of the guide roller, different unloading speeds can be achieved. The transport trolley can move in the horizontal direction. By adjusting the transport trolley, The vibration frequency and amplitude of the material trolley can control the falling position of scrap steel and realize the continuous addition of scrap steel.

Description

Scrap steel preheating device, arc melting equipment and preheating method

Technical field

The invention relates to the field of metallurgical technology, and specifically to a scrap steel preheating device, arc melting equipment and a preheating method.

Background technique

Energy saving, consumption reduction and environmental protection in electric arc furnace steelmaking have always been one of the core technologies in the development of global electric arc furnace steelmaking technology.

In traditional electric arc furnaces for steelmaking, scrap steel is loaded from the top of the furnace in two to three steps, and the scrap steel is melted by relying on the arc generated between the electrode and the scrap steel. Therefore, the traditional electric arc furnace can only send power to the furnace intermittently, and the power is cut off after a period of time, and the furnace cover is unscrewed to load materials. This greatly reduces the productivity of the electric arc furnace and increases the heat loss and energy consumption of the electric arc furnace. At the same time, a large amount of smoke and dust is discharged into the factory during loading, which increases the difficulty of dust removal and environmental protection. Intermittent electrodes produce open arcs with scrap steel, which increases the impact on the power grid and the harm of noise. Energy saving and consumption reduction of high-temperature flue gas generated by steelmaking is an important issue in electric arc furnace smelting. Among them, the use of flue gas waste heat to preheat scrap steel has always been received widespread attention. During the smelting process of electric arc furnace, a large amount of high-temperature flue gas will be produced. The temperature of these flue gases is as high as over 1000℃, and the exhaust volume is as high as 500~1200m ³ /(h·t). Utilizing the sensible heat of flue gas to preheat scrap steel will produce huge economic benefits.

As we all know, scrap preheating is one of the development directions of energy-saving technology for electric arc furnace steel. Currently, in the scrap preheating supporting electric arc furnaces, the representative methods include horizontal continuous transportation mode and shaft furnace mode. The equipment used is such as Kangsidi Electric arc furnace (Consteel electric arc furnace) and grate shaft electric arc furnace.

Among them, the technology of using electric arc furnace flue gas to preheat scrap steel is a technology that has been studied at home and abroad for more than 20 years. However, due to its high technical difficulty, only a few solutions have been put into practical use. Typical examples include vibrating continuous feeding. Consteel (US5400358-1992), finger shaft furnace (DE4025294A1-1992), shaft side push feeding (US2007/0013112A1) technology.

The horizontal scrap steel preheating device has attracted the attention of some enterprises because it does not have excessive requirements on the height of the factory building.

At present, the representative horizontal continuous feeding scrap steel preheating device is mainly the so-called continuous steelmaking electric arc furnace (Consteel) imported from abroad.

Consteel (US5400358-1992) is a horizontal continuous feeding technology that can achieve stable arc smelting in electric arc furnaces. It is environmentally friendly and reduces electrode consumption. It can greatly reduce the production process cost of electric arc furnaces. However, in this method, only the upper layer of scrap steel is heated, so The scrap steel preheating effect is not good. According to domestic and foreign reports, the average energy saving effect is only 25kwh per ton of steel. In addition, due to the need to improve the heat exchange efficiency of the raw material (scrap steel), the scrap steel in the conveyor trough is relatively thin on the conveyor belt, so the preheating time must be increased. The length of the hot section and the total length of the equipment can reach 90 to 100m, which is very unfavorable for the layout of the workshop; thirdly, this solution has serious dynamic seal leakage and requires a large capacity for fans.

The hot flue gas of the Kansidi electric arc furnace flows against the scrap steel in the preheating device. Since the scrap steel cannot be filled in the horizontal preheating device, a large part of the air flow flows in the upper part of the scrap steel layer, causing the scrap steel preheating at the bottom to flow. The thermal effect is poor. In order to achieve higher heat exchange, a 60-meter-long preheating tunnel is usually required. Since scrap steel contains chlorine-containing compounds, such as PVC, theoretically, incomplete combustion of these chlorine-containing compounds below 800°C will produce dioxins, especially incomplete combustion in the range of 300 to 500°C is most likely to produce dioxins. Dioxins, due to the long preheating tunnel of the Kangsidi furnace, the temperature continues to decrease after the heat exchange between the hot flue gas and the scrap steel, making the chlorine-containing compounds in the scrap steel very easy to burn incompletely between 300 and 500°C. Produce dioxins and pollute the environment.

The inherent shortcomings of the Consteel electric arc furnace are: 1. Although its inventor Intel Steel believes that the Consteel process developed by the company can preheat scrap steel to about 500°C, the equipment supplier Dexing Company of Italy also promotes that it can preheat scrap steel. Preheat to 400℃~600℃, and the production practice of Kyoei Steel Company shows that the temperature of the scrap steel after preheating is uneven (higher at the top and lower at the bottom), and the scrap steel at a distance of 600mm to 700mm from the surface When the temperature is <100°C, the energy-saving effect is only 25kwh/t steel, and the heat transfer efficiency is very low. The production practice of Consteel electric arc furnace in use in China also proves that the scrap preheating temperature of this equipment is low and the energy saving effect is poor. 2. The length of the equipment is very long. Generally, the total length of the preheating channel and loading conveyor is about 60 meters. It covers a large area. It is very difficult to install the equipment and renovate the old factory building, and the one-time investment is very high. 3. The air leakage is large, and a large amount of wild wind is mixed into the flue gas, which not only increases the burden on the dust removal fan, but also greatly hinders the recovery and utilization of the waste heat of the flue gas. 4. The operating rate of loading electromagnetic cranes is very high, some reaching more than 90%, and sometimes production will be affected due to loading.

The finger shaft electric arc furnace was developed and developed by the German FUCHS company in the early 1990s. It is a typical electric arc furnace scrap steel preheating device. The so-called "finger" refers to a single unit between the shaft furnace and the electric arc furnace connection interface. One or more rows of finger rests that can be opened and closed by mechanical means. In the electric arc furnace smelting process, scrap steel is added directly to the waste gas flow to make full use of the preheating ability of the waste gas. Not only the sensible heat of the flue gas is used, but the chemical energy of the combustible gas in the flue gas can be used for secondary combustion. Therefore, this type of scrap steel preheating technology with a supporting device has good preheating and energy saving effects because the flue gas can penetrate the scrap steel layer, and can reach 60 to 100kwh per ton of steel. However, in traditional shaft furnaces, due to the impact of scrap steel on the finger brackets Direct impact can easily lead to damage by scrap steel, which increases equipment maintenance and affects the promotion and use of scrap steel preheating technology. At the same time, due to the presence of a certain amount of light and thin materials in the scrap steel, the secondary combustion of combustible gas may cause partial melting of the scrap steel, causing the scrap steel in the shaft furnace to stick, causing the problem that the shaft furnace scrap steel cannot enter the electric arc furnace smoothly. For this reason, by preventing scrap steel from falling directly onto the finger bracket, the impact of the scrap steel feeding process can be significantly reduced and the maintenance of the equipment can be reduced. FUCHS Company has launched a new generation of FUCHS-COSS electric arc furnace, which is an improvement on the shaft furnace. It uses an independent pushing system to replace the original shaft. The pushing system is a water-free cooling system and is composed of cast iron plates, which avoids the original shaft problem. Water leakage will affect the smelting cycle, but the mechanical structure is huge and the operation is complex.

Although the vertical scrap steel preheating technology has high thermal efficiency and high scrap steel preheating temperature, it requires a high elevation of the factory building, huge equipment, high one-time investment, and is not suitable for the transformation of the old electric arc furnace steelmaking workshop. In a grate-type shaft furnace, the hot flue gas from the electric arc furnace enters from the lower end of the shaft and is discharged from the upper end of the shaft. In this way, the cross-section of the shaft must be large enough to allow the hot flue gas to flow through the gaps between the scrap steel. In actual production, the water-cooled finger grate is easily damaged by scrap steel, leaks, or gets stuck by scrap steel. The cost of equipment is high and the maintenance of the equipment is large. Therefore, grate-type shaft furnaces are only part of the large furnaces in electric arc furnace steelmaking. use.

Contents of the invention

The invention provides a scrap steel preheating device, arc melting equipment and a preheating method to solve the problem of equipment leakage in the prior art due to the deformation and cracking of finger-type mechanisms caused by the impact of falling scrap raw materials.

The technical solution adopted by the present invention to solve the technical problem is: a scrap steel preheating device, which includes: a vertical shaft, the upper end is a feed port, and the lower end side wall of the vertical shaft is provided with a discharge port; an unloader is arranged in the vertical shaft and Able to move in the vertical direction relative to the shaft, the unloader has an upper surface inclined toward the discharge port; the material transport trolley is capable of vibrating the material, and the inlet end of the material transport trolley is connected to the discharge port; the guide roller is provided At the discharge port and located above the entrance end of the material transport trolley, the guide roller can control the opening of the discharge port.

Further, the guide roller includes a telescopic rod, a swing rod and a guide roller. One end of the telescopic rod is hinged with the shell of the shaft, the other end of the telescopic rod is hinged with the rotation center of the guide roller, and one end of the swing rod is hinged with the shell of the shaft. The other end of the rod is hinged with the rotation center of the guide roller, and one end of the telescopic rod is misaligned with one end of the swing rod.

Further, a plurality of discharge rollers are provided at the upper end of the unloader. The plurality of discharge rollers are evenly spaced and form the upper surface of the unloader.

Further, the side wall of the unloader facing the discharge port is provided with a flue gas through hole for the passage of preheated flue gas, and the flue gas through hole is used to connect the upper surface of the unloader and the inlet of the electric arc furnace respectively.

Further, a flue gas pipe is provided on the lower side of the feed inlet of the shaft, and a flue gas analysis component and a temperature measurement component are provided at the flue gas pipe.

Further, the scrap steel preheating device also includes a lifting mechanism, which is arranged below the unloader and can drive the unloader to move in the vertical direction relative to the shaft.

Further, a fuel spray gun and a combustion-supporting oxygen gun are provided in the shaft. The fuel spray gun and the combustion-supporting oxygen gun are both located below the feed port and above the unloader.

Further, a feeding assembly for feeding material is provided at the feeding inlet of the shaft.

Further, the feed assembly includes: a shaft furnace hopper, which is a funnel-shaped structure. The small diameter end of the shaft furnace hopper is connected to the feed port. The large diameter end of the shaft furnace hopper is located vertically along the small diameter of the shaft furnace hopper. Above the end; the first sealing slide plate is arranged at the large diameter end of the shaft furnace receiving hopper and can control the opening and closing of the large diameter end of the shaft furnace receiving hopper; the second sealing sliding plate is arranged at the small diameter end of the shaft furnace receiving hopper and can control the opening and closing of the shaft furnace receiving hopper. The furnace is opened and closed by the small diameter end of the hopper, and the first sealing slide plate and the second sealing slide plate can move independently.

The feeding component includes: a transmission guide rail, which is arranged at an angle and connects the feed port and the ground material pile; a hopper, which is installed on the transmission guide rail and can move with the transmission guide rail, and the hopper can add materials to the feed port.

The invention also provides an electric arc melting equipment, which includes an electric arc furnace and the above-mentioned scrap steel preheating device. The inlet of the electric arc furnace is connected to the outlet of the material transport trolley.

The invention further provides a preheating method, which includes the following steps: Step 10, raise the unloader to the set highest position, and add scrap steel into the vertical shaft through the feed port to form a scrap steel accumulation area; Step 20, turn on the fuel The spray gun and combustion-supporting oxygen gun heat the scrap accumulation area; step 30, when the scrap accumulation area is heated to the set temperature, lower the unloader to connect the scrap accumulation area with the discharge port, and at the same time open the transport trolley to the electric arc furnace Transport scrap steel; Step 40. As the electric arc furnace melts scrap steel, a large amount of high-temperature flue gas will be generated in the electric arc furnace. Multiple roller gap pairs are provided along the flue gas through hole of the unloader and the upper end of the unloader. Preheat the scrap steel accumulation area; Step 50, adjust the opening of the fuel spray gun and combustion oxygen gun through the measurement results of the flue gas analysis component and the temperature measurement component; Step 60, after the molten steel in the electric arc furnace reaches the set requirements, the electric arc furnace Carry out tapping operation; step 70, cycle step 10, step 30, step 40, step 50 and step 60 in sequence.

Further, in step 30, the tapping speed of the discharge port is controlled through the unloader and the guide roller.

The beneficial effect of the present invention is that the unloader can be adjusted in the height direction. By adjusting the height of the unloader and the position of the guide roller, different unloading speeds can be achieved. At the same time, the above-mentioned guide roller can close the discharge port, so as to To achieve the purpose of stopping the feeding; the material transport trolley can move horizontally. By adjusting the vibration frequency and amplitude of the material transport trolley, the falling position of the scrap steel can be controlled to realize the continuous addition of scrap steel.

Description of drawings

The description and drawings that constitute a part of this application are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the attached picture:

Figure 1 is a schematic structural diagram of an embodiment of the present invention;

Figure 2 is a schematic diagram of the process of continuously adding scrap steel to the shaft;

Figure 3 is a schematic diagram of the unloader, feeding chute feeding process and feeding process;

Figure 4 is a schematic diagram of the unloader, continuous feeding of feed chute and scrap melting process;

Figure 5 is a schematic diagram of the unloader, feed chute stopping feeding and molten steel smelting process;

Figure 6 is a schematic diagram of the shaft charging process and the molten steel smelting process;

Figure 7 is a schematic diagram of the remaining molten steel amount after tapping and the feeding process of the unloader and feeding chute;

Figure 8 is a schematic diagram of the smelting process using hopper loading.

Reference numbers in the figure: 10. Shaft; 11. Flue gas pipe; 12. Flue gas analysis component; 13. Temperature measurement component; 14. Fuel spray gun; 15. Combustion oxygen gun; 16. Shell frame; 20. Unloading 21. Lifting mechanism; 211. Connectors; 22. Flue gas holes; 23. Unloading roller; 30. Material transport trolley; 31. Feed chute; 40. Guide roller; 41. Telescopic rod; 42. Swing Rod; 43. Guide roller; 50. Electric arc furnace; 51. Furnace cover; 52. Conductive cross arm; 53. Cluster oxygen lance; 54. Electrode lifting device; 55. Rotating lifting device; 56. Lower furnace shell tilting mechanism; 61 , Shaft furnace receiving hopper; 62. First sealing sliding plate; 63. Second sealing sliding plate; 70. Material basket; 71. Transfer guide rail; 72. Hopper; 73. Lifting vehicle; 74. Dumping mechanism; 75. Traction device; 76 , limit stop; 80, base; 81, limit lock component; 82, seal component.

Detailed ways

It should be noted that, as long as there is no conflict, the embodiments and features in the embodiments of this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

As shown in FIGS. 1 to 7 , an embodiment of the present invention provides a scrap steel preheating device, including a shaft 10 , an unloader 20 , a transport trolley 30 and a guide roller 40 . The upper end of the shaft 10 is a feed port, and the lower end side wall of the shaft 10 is provided with a discharge port. The unloader 20 is disposed in the shaft 10 and can move in a vertical direction relative to the shaft 10 . The unloader 20 has an upper surface inclined toward the discharge opening. The material transporting trolley 30 can vibrate and transport materials. The inlet end of the material transporting trolley 30 is sealingly connected to the discharge port, and the outlet end of the material transporting trolley 30 is connected to the electric arc furnace 50 . The guide roller 40 is disposed at the discharge port and is located above the entrance end of the material transport trolley 30 . The guide roller 40 can control the opening of the discharge port.

The present invention proposes for the first time a method of adding scrap steel using the unloader 20 and the transport trolley 30, eliminating the finger-shaped valve group mechanism that is cooled by water in the traditional design, and avoiding deformation and cracking of the finger-type mechanism due to the impact of the falling scrap raw materials. The disadvantages of equipment leakage are eliminated, and the steel pushing mechanism is eliminated. The large frame and hydraulic mechanism of the steel pushing structure are reduced. The inclined upper surface of the unloader 20 is used to realize the falling of scrap steel. Combined with the vibration feeding of the transport trolley 30, Realize the continuous addition of scrap steel.

It should be noted that the above-mentioned shaft 10 , unloader 20 and material transport trolley 30 are all arranged on the base 80 , and a sealing assembly 82 is arranged between the unloader 20 and the electric arc furnace 50 .

The above-mentioned material transport trolley 30 is equipped with running wheels at the bottom, and the base 80 is provided with a limit locking assembly 81 at a position close to the electric arc furnace 50, which can limit and fix the material transport trolley 30 and at the same time lock the material transport trolley 30 to avoid During the feeding process of the feeding chute 31, the material transport trolley 30 moves.

The guide roller 40 includes a telescopic rod 41, a swing rod 42 and a guide roller 43. One end of the telescopic rod 41 is hinged with the housing frame 16 of the shaft 10. The other end of the telescopic rod 41 is hinged with the rotation center of the guide roller 43. One end of the swing rod 42 It is hinged with the shell frame 16 of the shaft 10 , the other end of the swing rod 42 is hinged with the rotation center of the guide roller 43 , and one end of the telescopic rod 41 is offset from one end of the swing rod 42 .

The scrap steel preheating device also includes a lifting mechanism 21. The lifting mechanism 21 is arranged below the unloader 20 and can drive the unloader 20 to move in the vertical direction relative to the shaft 10. The lifting mechanism 21 and the unloader 20 are connected through a connecting piece 211.

The unloader 20 can be adjusted in the height direction. By adjusting the height of the unloader 20 and through the joint action of the unloader 20 and the guide roller 40, different discharge speeds can be achieved; at the same time, the above-mentioned guide roller 43 can seal the discharge. mouth to achieve the purpose of stopping feeding. The material transport trolley 30 can move in the horizontal direction, and the vibration frequency and amplitude of the material transport trolley 30 can be adjusted to control different scrap steel falling positions.

Preferably, the material transport trolley 30 can move in the horizontal direction to realize dynamic adjustment of the scrap steel dropping position of the feeding chute 31; the upper feeding chute 31 adopts a telescopic structural design, when the material transport trolley 30 cannot meet the scrap steel dropping position When required, the scrap throwing position can be dynamically adjusted by adjusting the length of the feeding chute 31. The feeding chute 31 of the material transport trolley 30 can use mechanical vibration to transport scrap steel horizontally, or can also use a grate machine to transport scrap steel. The material transport trolley 30 uses a variable frequency motor to realize dynamic adjustment of the vibration amplitude and frequency of the feeding trough to meet different feeding speed requirements, and the feeding capacity is controlled at a feeding speed of 0.4 to 4.5 tons/minute. The feeding chute 31 of the material transport trolley 30 can adopt a U-shaped structure, and at the same time, a field-shaped protrusion is processed along the inner wall of the U-shaped chute to increase the friction of the feeding chute 31 to the scrap steel and prevent the scrap steel from slipping and rolling.

As shown in FIG. 1 , a plurality of discharge rollers 23 are provided at the upper end of the unloader 20 . The plurality of discharge rollers 23 are evenly spaced and form the upper surface of the unloader 20 . The rotation of the discharge roller 23 can promote the scrap steel to fall to the feeding chute 31 of the transport trolley 30, making the scrap steel easier to transport, thereby eliminating the steel pushing mechanism and reducing the large frame and hydraulic mechanism of the steel pushing structure. .

In the embodiment of the present invention, the upper surface of the unloader 20 adopts an inclined arrangement, and the angle between the upper surface and the horizontal plane is between 30° and 60°.

The side wall of the unloader 20 facing the discharge port is provided with a flue gas through hole 22 for the passage of preheated flue gas. The flue gas through hole 22 is respectively connected to the upper surface of the unloader 20 and the inlet of the electric arc furnace 50 . A flue gas duct 11 is provided on the lower side of the feed opening of the shaft 10 , and a flue gas analysis component 12 and a temperature measurement component 13 are disposed at the flue gas duct 11 . A fuel spray gun 14 and a combustion-supporting oxygen gun 15 are provided in the shaft 10 . The fuel spray gun 14 and the combustion-supporting oxygen gun 15 are both located below the feed port and above the unloader 20 .

Preferably, the guide roller 40 adopts a porous design, and the internal hollow form allows high-temperature flue gas to pass through. The flue gas can enter the shaft 10 through the guide roller 40 and the upper part of the unloader 20 to achieve smooth flow of the flue gas. The guide roller 40 can also control the height of scrap steel on the feeding trough 31 to achieve uniform horizontal distribution of scrap steel on the feeding trough.

The height of the side wall of the feeding chute 31 is greater than 200 mm, which avoids the possibility of scrap steel falling from the side wall of the feeding chute 31 due to rolling, vibration, etc. during the feeding process.

As the molten steel in the electric arc furnace 50 is smelted, a large amount of high-temperature flue gas (flue gas temperature is between 1300 and 1600° C.) is formed inside the furnace of the electric arc furnace 50 . The gap and the upper cavity of the material roller 23 enter the shaft 10, and the scrap steel is preheated inside the shaft 10. The flue gas analysis component 12 and the temperature measurement component 13 installed on the shaft 10 are used to monitor and detect the flue gas temperature and the main components of the flue gas. , according to the flue gas temperature and flue gas composition, adjust the fuel lance 14 and the combustion oxygen lance 15 to ensure that the scrap steel preheating temperature reaches the process requirements, adjust the scrap steel loading speed, with the continuous addition of scrap steel and the continuous progress of smelting, The large amount of high-temperature flue gas generated in the electric arc furnace 50 continues to preheat the scrap steel, and at the same time, the fuel lance 14 and the combustion oxygen lance 15 can be closed.

It should be noted that for the first heat of steel smelted by the electric arc furnace 50, since there is no molten steel and flue gas in the hearth of the electric arc furnace 50, it is necessary to open the fuel lance 14 and the combustion oxygen lance 15 on the shaft 10 to heat the scrap while continuing to add Scrap steel. When the temperature of the scrap steel in the lower part of the shaft 10 reaches 600°C, the unloader 20 is lowered, the vibration mechanism of the transport trolley 30 is turned on, the discharge roller 23 on the top of the unloader 20 is turned on, and the rotation of the discharge roller 23 is used to promote the scrap steel to fall to The feeding chute 31 of the transport trolley 30 uses the vibration of the transport trolley 30 to transport the scrap steel into the electric arc furnace; at the same time, the guide roller 40 can move up and down under the action of the driving mechanism to prevent the scrap steel raw materials from hitting the outlet position. The above-mentioned guide The roller 40 has the function of closing the discharge port according to the process requirements.

In the embodiment of the present invention, a feeding assembly for feeding material is provided at the feeding inlet of the shaft 10 . The feeding assembly includes a shaft furnace hopper 61 , a first sealing slide 62 and a second sealing slide 63 . The shaft furnace receiving hopper 61 has a funnel-shaped structure. The small diameter end of the shaft furnace receiving hopper 61 is connected to the feed port. The large diameter end of the shaft furnace receiving hopper 61 is located above the small diameter end of the shaft furnace receiving hopper 61 in the vertical direction. The first sealing slide plate 62 is provided at the large diameter end of the shaft furnace receiving hopper 61 and can control the opening and closing of the large diameter end of the shaft furnace receiving hopper 61 . The second sealing sliding plate 63 is provided at the small diameter end of the shaft furnace receiving hopper 61 and can control the opening and closing of the small diameter end of the shaft furnace receiving hopper 61, and the first sealing sliding plate 62 and the second sealing sliding plate 63 can move independently.

During operation, the basket 70 carrying the scrap steel charge is transported to the top of the shaft furnace hopper 61 through the crane, the first sealing slide 62 is opened, the second sealing slide 63 is closed, and the scrap raw materials are added into the shaft furnace hopper 61. The unloader 20 is raised to the highest position, the first sealing slide 62 is closed, and the second sealing slide 63 is opened. The scrap steel raw materials gradually fall to the lower section of the shaft 10 and form a scrap steel accumulation area. The subsequent falling scrap steel gradually falls on the previously fallen scrap. Scrap steel above.

Of course, the feeding assembly is not limited to the above embodiment. As shown in FIG. 8 , the feeding assembly includes a conveying guide rail 71 , a hopper 72 , a lifting vehicle 73 , a dumping mechanism 74 , a traction device 75 and a limiting block 76 .

The conveying guide rail 71 is arranged obliquely and connects the feed port and the floor material pile. The lifting car 73 is disposed on the conveying guide rail 71 and can move along with the conveying guide rail 71 . The above-mentioned hopper 72 is disposed on the lifting car 73 and is connected to the lifting car 73 through the dumping mechanism 74 . The above-mentioned traction device 75 is disposed at the upper end of the transmission guide rail 71 and can drive the transmission guide rail 71 to move, and the limiting stop 76 can limit the movement displacement of the lifting vehicle 73 . The above-mentioned hopper 72 can dump the scrap steel into the shaft 10, and other structures are the same as in the previous embodiments and will not be described again here.

Further, the present invention can adopt the method of loading the material in the basket, the form of the inclined hopper, or the form of the ladder chain bucket conveyor to add the scrap steel raw materials into the shaft receiving hopper. The feeding mechanism can also use a belt conveyor for continuous feeding.

It should be noted that the vibrating working surfaces of the discharge roller 23, the guide roller 40, and the transport trolley 30 are made of high-temperature-resistant wear-resistant materials, preferably heat-resistant steel and heat-resistant alloys, to extend the service life of the equipment. At the same time, the above-mentioned wear-resistant parts The partial installation method can realize partial replacement after wear and tear, which reduces the operating cost of the equipment.

The present invention also provides an electric arc melting equipment, which includes an electric arc furnace 50 and the above-mentioned scrap steel preheating device. The entrance of the electric arc furnace 50 is connected to the exit of the material transport trolley 30 .

Among them, in the embodiment of the present invention, the above-mentioned electric arc furnace 50 mainly includes a furnace bottom, a furnace shell, a furnace wall, a furnace lid 51, an electrode and a conductive cross arm 52, an electrode lifting device 54, a furnace lid support frame, a load-bearing member, and a rotating lifting device. 55. Lower furnace shell tilting mechanism 56. The specific connection structure is similar to the structure of the electric arc furnace in the prior art, and will not be described again here.

During operation, as the scrap steel in the electric arc furnace 50 continues to be added, the scrap steel falls into the molten steel pool, and the molten steel molten pool heats and melts the scrap steel. At the same time, the cluster oxygen lance 53 on the side wall of the electric arc furnace 50 is turned on to blow the molten steel. Oxygen, according to actual needs, the side wall carbon gun can be used to inject carbon powder into the furnace, and the cluster oxygen gun 53 and the carbon gun can be used to stir, carburize, oxidize and other operations on the molten pool.

As the molten steel in the electric arc furnace 50 is smelted, when the quality, temperature and composition of the molten steel in the furnace furnace reach the target requirements, the rotating lifting device 55 is driven to raise the furnace cover 51 to a certain height to achieve a small gap between the furnace cover 51 and the furnace wall. Separate, drive the lower furnace shell tilting mechanism 56 connected to the lower furnace shell frame of the electric arc furnace, tilt the lower furnace shell, use the tapping port at the bottom of the furnace to perform the steel tapping operation, and pour molten steel that meets the subsequent process requirements into the molten steel ladle. After the molten steel in the ladle reaches a predetermined quality, and a predetermined remaining molten steel is retained in the furnace, the lower furnace shell tilting mechanism 56 connected to the lower furnace shell frame is adjusted to adjust the electric arc furnace to the smelting state; the electric arc furnace can continue to tap during the tapping process. Scrap steel is added to the shaft 10 and scrap steel is preheated. At the same time, scrap steel preheated to a predetermined temperature is continuously added to the furnace hearth. The electrode does not need to be raised, lowered or powered off, so that scrap steel raw materials can be continuously added to the electric arc furnace hearth.

After the last tapping operation is completed, the scrap steel continues to be heated, the electrodes continue to heat, the scrap steel continues to be added to the molten pool, and the retained liquid molten steel is used to continue to melt the scrap steel. The scrap steel continues to melt to form a larger molten pool. As the molten steel continues to increase, it reaches After predetermining the quality, temperature and composition of the molten steel, the tapping operation can be carried out. After the tapping operation is completed, the electric arc furnace enters the next smelting cycle. Shaft 10 can realize non-intermittent continuous feeding and scrap preheating. Electric arc furnace 50 can realize non-intermittent feeding of scrap steel into the furnace and non-intermittent heating of electrodes. The smelting of qualified molten steel can achieve stable periodic tapping and predetermined remaining molten steel to meet the needs of subsequent processes. .

An embodiment of the present invention also provides a preheating method, which includes the following steps:

Step 10: Raise the unloader 20 to the set highest position, and add scrap steel into the shaft 10 through the feed port to form a scrap steel accumulation area;

Step 20: Turn on the fuel spray gun 14 and the combustion oxygen gun 15 to heat the scrap steel accumulation area;

Step 30: When the scrap steel accumulation area is heated to the set temperature, lower the unloader 20 to connect the scrap steel accumulation area with the discharge port, and at the same time open the transport trolley 30 to transport scrap steel to the electric arc furnace 50, wherein, through the unloader 20 and guide roller 40 control the tapping speed of the discharge port;

Step 40: As the electric arc furnace 50 melts scrap steel, a large amount of high-temperature flue gas will be generated in the electric arc furnace 50. The high-temperature flue gas is provided with multiple rollers along the flue gas through hole 22 of the unloader 20 and the upper end of the unloader 20. Preheat the scrap steel accumulation area in the gap;

Step 50: Adjust the openings of the fuel spray gun 14 and the combustion oxygen gun 15 through the measurement results of the flue gas analysis component 12 and the temperature measurement component 13;

Step 60: After the molten steel in the electric arc furnace 50 reaches the set requirement, tap the electric arc furnace 50;

Step 70: Repeat step 10, step 30, step 40, step 50 and step 60 in sequence.

The details of steps 10 and 20 are as follows, as shown in Figure 1 and Figure 2,

The basket 70 carrying the scrap steel charge is transported to the top of the shaft 10 through the crane, the first sealing slide 62 is opened, the second sealing slide 63 is closed, the scrap steel raw materials are added into the shaft furnace hopper 61, and at the same time, the unloader 20 liters To the highest position, the guide roller 40 and the discharger 20 are used to seal the outlet of the shaft 10 . Then the first sealing slide 62 is closed, the second sealing slide 63 is opened, and the scrap steel raw materials gradually fall to the lower section of the shaft, and a scrap steel accumulation area is formed.

For the first heat of steel smelted by the electric arc furnace 50, since there is no molten steel and flue gas in the hearth of the electric arc furnace 50, the fuel lance 14 and the combustion oxygen lance 15 on the shaft 10 are turned on to heat the scrap steel, while continuing to add scrap steel; the shaft furnace receives the hopper Scrap steel in 61 continues to be added to shaft 10. The specific operation of step 30 is shown in Figure 3 and Figure 4. When the temperature of the scrap steel in the lower part of the shaft 10 reaches 600°C, lower the unloader 20, turn on the vibration mechanism of the transport trolley 30, and turn on the unloader on the top of the unloader 20. The material roller 23 uses the rotation of the discharge roller 23 to promote the scrap steel to fall to the material transport trolley 30, and uses the vibration of the material transport trolley 30 to transport the scrap steel into the electric arc furnace.

At the same time, the scrap steel raw materials in the basket 70 can be added to the shaft furnace hopper 61; the guide roller 40 can move up and down under the action of the driving mechanism to prevent the scrap steel raw materials from hitting the exit position; at the same time, according to the process requirements, there is a closed shaft furnace discharge port effect. Referring to Figure 5, when the scrap steel in the shaft 10 drops to a certain height, the second sealing slide 63 is closed, the first sealing slide 62 is opened, and the basket 70 loaded with scrap steel raw materials is lifted by the overhead crane to the shaft furnace hopper. 61, open the bottom discharging mechanism of the basket 70, and add the scrap steel raw materials into the shaft furnace receiving hopper 61 at the upper part of the shaft 10. After the scrap steel completely falls into the shaft furnace receiving hopper 61, close the first sealing slide 62 and open the second sealing The sliding plate 63 adds scrap steel raw materials into the shaft 10 .

The unloader 20 can be adjusted in the height direction. By adjusting the height of the unloader 20 and utilizing the cooperation of the guide rollers 40, different unloading speeds can be achieved. The transport trolley 30 can move in the horizontal direction, and the vibration frequency and amplitude of the transport trolley 30 can be adjusted to control different scrap falling positions. The scrap steel falling into the bottom of the furnace is accumulated at the bottom of the furnace. When the scrap steel raw materials are accumulated at the bottom of the furnace, When the predetermined amount is reached, the electrode lifting device 54 is started to lower the height of the electrode, and electricity is applied to heat the scrap steel. As the arc continues to be heated, the scrap steel gradually melts, forming a liquid molten pool at the bottom of the furnace and a foamed slag layer on the surface of the molten steel molten pool. , the arc is buried in the foam slag for continuous heating.

As the scrap steel continues to be added, after the scrap steel in the shaft 10 is completely loaded into the electric arc furnace, there is no scrap steel to be preheated in the shaft 10, and the unloading action of the unloader 20 is stopped.

Steps 40 and 50 are shown in Figure 6. The lifting mechanism 21 is used to lift the unloader 20 to the highest position. At the same time, the unloader 20 and the guide roller 40 are used to seal the bottom of the shaft 10, and the second sealing slide plate 63 is closed. Open the first sealing slide 62, use the crane to lift the basket 70 loaded with scrap steel raw materials to the upper part of the shaft furnace receiving hopper 61, open the bottom discharge mechanism of the basket 70, and add the scrap steel raw materials to the shaft furnace receiving hopper at the upper part of the shaft. 61, after the scrap steel completely falls into the receiving funnel, the first sealing slide plate 62 is closed, the second sealing slide plate 63 is opened, and the scrap steel raw materials are added into the shaft 10.

After the scrap steel of the predetermined quality is completely loaded into the electric arc furnace, the molten steel pool heats and melts the scrap steel. At the same time, the cluster oxygen lance 53 on the side wall of the electric arc furnace is turned on to blow oxygen into the molten steel. According to actual needs, a side wall carbon gun can be used Inject carbon powder into the furnace, and use the cluster oxygen gun 53 and the carbon gun to stir, carburize, oxidize and other operations on the molten pool.

As the molten steel in the electric arc furnace is smelted, a large amount of high-temperature flue gas is formed inside the furnace of the electric arc furnace 50. The high-temperature flue gas enters the shaft 10 along the flue gas through hole 22, the gap and the upper cavity of the discharge roller 23, and scrap steel is processed inside the shaft. Perform preheating, use the flue gas analysis component 12 and temperature measurement component 13 installed in the shaft 10 to monitor and detect the flue gas temperature and main components of the flue gas, and adjust the fuel nozzle 14 and combustion oxygen gun 15 according to the flue gas temperature and flue gas components to ensure Under the premise that the scrap steel preheating temperature reaches the process requirements, the scrap loading speed is adjusted. As the scrap steel continues to be added and the smelting continues, a large amount of high-temperature flue gas generated in the furnace of the electric arc furnace 50 continues to preheat the scrap steel, and at the same time, the scrap steel can be preheated. Close the fuel spray gun 14 and the combustion oxygen gun 15.

Steps 60 and 70 are shown in Figure 7. When the quality, temperature and composition of the molten steel in the furnace furnace reach the target requirements, the furnace cover lifting device 52 is driven to raise the furnace cover 51 to a certain height to achieve the alignment between the furnace cover 51 and the furnace wall. After the small gap is separated, the lifting device 56 connected to the lower furnace shell frame of the electric arc furnace is driven, the lower furnace shell is tilted, and the tapping port at the bottom of the furnace hearth is used to perform the tapping operation. The molten steel that meets the subsequent process requirements is poured into the molten steel ladle. After the molten steel in the ladle reaches the predetermined quality, the predetermined remaining molten steel is retained in the furnace. The lifting device connected to the lower furnace shell frame is adjusted to adjust the electric arc furnace to the smelting state. During the tapping process of the electric arc furnace, scrap steel can be continuously added to the shaft 10 and scrap steel is preheated. At the same time, the scrap steel preheated to a predetermined temperature is continuously added to the furnace hearth. The electrode does not need to be lifted or cut off, so that scrap steel raw materials can be continuously added to the electric arc furnace 50. hearth.

After the last tapping operation is completed, the scrap steel continues to be preheated, the electrodes continue to heat, the scrap steel continues to be added to the molten pool, and the retained liquid molten steel is used to continue to melt the scrap steel. The scrap steel continues to melt to form a larger molten pool. As the molten steel continues to increase, After reaching the predetermined quality, temperature and composition of the molten steel, the tapping operation can be carried out. After the tapping operation is completed, the electric arc furnace enters the next smelting cycle. The shaft preheater can realize non-intermittent continuous feeding and scrap preheating. The electric arc furnace can realize non-intermittent adding of scrap steel into the furnace and non-intermittent heating of the electrodes. The smelting of qualified molten steel can achieve stable periodic tapping and predetermined remaining molten steel to meet the requirements of subsequent processes. need. From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects:

The invention can realize continuous preheating of scrap steel, and at the same time can use the fuel spray gun and the combustion-supporting oxygen gun to preheat the scrap steel of the first furnace of smelting, and can measure the flue gas temperature through the flue gas analyzer and the temperature measuring instrument, and provide feedback control. The input amount of the combustion-supporting oxygen gun and the fuel spray gun simultaneously burns and releases heat for the combustible gases in the flue gas, eliminating the production of toxic substances such as dioxins in the flue gas.

The invention uses an unloader to capture the falling scrap steel, realizes continuous heating of the scrap steel, and continues the automatic falling process. It eliminates the finger-shaped valve group or other forms of control mechanisms of the traditional shaft furnace preheater and avoids the failure of the scrap steel charge during the falling process. Disadvantages of the electric arc furnace shutting down due to leakage from the finger valve group due to impact. An unloader and a transport trolley are used to feed scrap steel into the electric arc furnace. A discharge roller is installed on the upper part of the unloader. The rotation and tilting surface of the discharge roller are used to achieve smooth falling of scrap steel, and a smaller driving force and structure are used. Realize the feeding action of scrap steel raw materials.

The lifting of the unloader can reduce the impact of scrap steel on the unloading roller, and at the same time, it can accurately adjust the unloading speed of scrap steel. Due to the cooperative use of the guide roller and the transport trolley, the feeding speed of the transport trolley can be adjusted in real time. Realizing the continuous addition of scrap steel at a constant speed or changing speed is conducive to the smoothness of the feeding and reducing the violent fluctuations of the molten pool liquid level. By utilizing the lifting and lowering of the unloader and the cooperation of the guide rollers, the addition of scrap steel can be stopped as needed. , the scrap steel can completely seal the discharge port of the shaft furnace and realize the stop of adding scrap steel.

The transport trolley can have a weighing function to accurately record and control the amount of scrap added.

The above are only specific embodiments of the present invention and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the patent protection scope of the present invention, should still be covered by this patent. category. In addition, the technical features in the present invention can be freely combined with each other, between technical features and technical solutions, and between technical solutions and technical solutions.

Claims (10)

1. A scrap steel preheating device, characterized by comprising:

the upper end of the vertical shaft (10) is provided with a feed inlet, and the side wall of the lower end of the vertical shaft (10) is provided with a discharge outlet;

-a discharger (20) arranged in the shaft (10) and movable in a vertical direction relative to the shaft (10), the discharger (20) having an upper surface inclined towards the discharge opening;

the material conveying trolley (30) can vibrate and convey materials, and the inlet end of the material conveying trolley (30) is connected with the discharge port;

the guide roller (40) is arranged at the discharge port and is positioned at the upper side of the inlet end of the material conveying trolley (30), and the opening degree of the discharge port can be controlled by the guide roller (40);

the guide roller (40) comprises a telescopic rod (41), a swinging rod (42) and a guide roller (43), one end of the telescopic rod (41) is hinged with the shell frame (16) of the vertical shaft (10), the other end of the telescopic rod (41) is hinged with the rotation center of the guide roller (43), one end of the swinging rod (42) is hinged with the shell frame (16) of the vertical shaft (10), the other end of the swinging rod (42) is hinged with the rotation center of the guide roller (43), and one end of the telescopic rod (41) is arranged in a staggered mode with one end of the swinging rod (42);

the upper end of the discharger (20) is provided with a plurality of discharge rollers (23), and the discharge rollers (23) are uniformly distributed at intervals to form the upper surface of the discharger (20);

the side wall of the discharger (20) facing the discharge hole is provided with a flue gas through hole (22) for preheating flue gas to pass through, and the flue gas through hole (22) is used for respectively connecting the upper part of the upper surface of the discharger (20) and the inlet of the electric arc furnace (50).

2. Scrap steel preheating device according to claim 1, characterized in that the lower side of the feed opening of the shaft (10) is provided with a flue gas duct (11), the flue gas duct (11) being provided with a flue gas analysis assembly (12) and a temperature measurement assembly (13).

3. Scrap steel preheating device according to claim 1, characterized in that it further comprises a lifting mechanism (21), which lifting mechanism (21) is arranged below the discharger (20) and is able to drive the discharger (20) in a vertical direction in relation to the shaft (10).

4. Scrap steel preheating device according to claim 1, characterized in that a fuel lance (14) and a combustion-supporting oxygen lance (15) are arranged in the shaft (10), both the fuel lance (14) and the combustion-supporting oxygen lance (15) being located below the feed opening and above the discharger (20).

5. Scrap steel preheating device according to claim 1, characterized in that the feed opening of the shaft (10) is provided with a feed assembly for feeding.

6. The scrap steel preheating device of claim 5 wherein the feed assembly includes:

a shaft furnace receiving hopper (61) in a funnel-shaped structure, wherein the small diameter end of the shaft furnace receiving hopper (61) is connected with the feeding hole, and the large diameter end of the shaft furnace receiving hopper (61) is positioned above the small diameter end of the shaft furnace receiving hopper (61) along the vertical direction;

a first seal slide plate (62) which is provided at the large diameter end of the shaft furnace receiving hopper (61) and can control the opening and closing of the large diameter end of the shaft furnace receiving hopper (61);

the second sealing slide plate (63) is arranged at the small diameter end of the shaft furnace receiving hopper (61) and can control the opening and closing of the small diameter end of the shaft furnace receiving hopper (61), and the first sealing slide plate (62) and the second sealing slide plate (63) can move independently.

7. The scrap steel preheating device of claim 5 wherein the feed assembly includes:

a conveying guide rail (71) which is obliquely arranged and connects the feed inlet and the ground material pile;

and a hopper (72) which is arranged on the conveying guide rail (71) and can move along with the conveying guide rail (71), wherein the hopper (72) can feed materials to the feeding hole.

8. An arc melting apparatus comprising an arc furnace (50) and a scrap preheating device, characterized in that the scrap preheating device is a scrap preheating device according to any one of claims 1 to 7, the inlet of the arc furnace (50) being connected to the outlet of the transporting trolley (30).

9. A preheating method, characterized in that the scrap steel preheating device according to any one of claims 1 to 7 is employed, comprising the steps of:

step 10, lifting a discharger (20) to a set highest position, and adding scrap steel into a vertical shaft (10) through a feed inlet to form a scrap steel accumulation area;

step 20, starting a fuel spray gun (14) and a combustion-supporting oxygen gun (15) to heat the scrap steel accumulation area;

step 30, when the scrap steel accumulation area is heated to a set temperature, reducing the discharger (20) to enable the scrap steel accumulation area to be connected with a discharge hole, and simultaneously starting a conveying trolley (30) to convey the scrap steel into an electric arc furnace (50);

step 40, along with smelting the scrap steel by the electric arc furnace (50), a large amount of high-temperature flue gas is generated in the electric arc furnace (50), and a plurality of roller gaps are arranged along the flue gas through holes (22) of the discharger (20) and the upper end of the discharger (20) to preheat the scrap steel stacking area;

step 50, adjusting the opening degrees of the fuel spray gun (14) and the combustion-supporting oxygen gun (15) according to the measurement results of the flue gas analysis assembly (12) and the temperature measurement assembly (13);

60, after the molten steel in the electric arc furnace (50) reaches a set requirement, tapping the electric arc furnace (50);

step 70, sequentially looping through the steps 10, 30, 40, 50 and 60.

10. The preheating method according to claim 9, characterized in that in said step 30, the tapping speed of the tap hole is controlled by means of the discharger (20) and guide rollers (40).