Pellet-electric furnace cogeneration system and method

Abstract

The present application belongs to the technical field of steel metallurgical production, and particularly relates to a pellet-electric furnace cogeneration system and method, wherein the system comprises: a chain grate machine for drying and preheating carbon-containing green pellets; a rotary kiln connected with the chain grate machine for reducing the preheated green pellets to generate metallized pellets and reducing gas; a waste gas utilization device for introducing the reducing gas into the chain grate machine for waste heat utilization, and using the utilized gas as auxiliary fuel for the chain grate machine combustion section and the rotary kiln; and a horizontal continuous charging electric furnace with a scrap steel preheating section communicated with a rotary kiln discharge end, which utilizes high-temperature metallized pellet waste heat and electric furnace flue gas to preheat the scrap steel, and the preheated material is fed into the electric furnace body for smelting. The present application realizes hot-state direct charging of metallized pellets into the electric furnace, avoids heat loss in the cooling and transfer process, significantly reduces electric furnace smelting energy consumption, and improves production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of iron and steel metallurgical production technology, and particularly relates to a pelletizing-electric furnace co-production system and method. Background Technology

[0002] In steel production, metallized pellet production and electric arc furnace smelting are two relatively independent processes. In the traditional production model, the metallized pellets produced by the chain grate rotary kiln need to be cooled, stored, and transferred before being sent to the electric arc furnace for smelting. During this process, a large amount of heat is lost from the metallized pellets, which means that the electric arc furnace smelting requires additional energy to heat the materials, resulting in high overall production energy consumption.

[0003] Meanwhile, the rotary kiln generates a large amount of waste gas containing reducing gases during the production of metallized pellets. Traditional treatment methods mostly involve direct discharge or simple combustion, which fails to fully utilize the heat energy and reducing components in the waste gas, resulting in energy waste. In addition, the high-temperature flue gas generated during the electric furnace smelting process is mostly discharged directly after dust removal treatment, and the large amount of heat it carries is not effectively recovered, further increasing the overall energy consumption and environmental pressure of production.

[0004] Therefore, there is an urgent need for a cogeneration system and method that can achieve synergistic coupling between metallized pellet production and electric furnace smelting, and efficient energy utilization, in order to solve the problems of high energy consumption and serious energy waste in existing technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a pelletizing-electric furnace co-production system and method to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides a pelletizing-electric furnace co-production system, comprising: The chain grate machine includes a drying section, a preheating section I, and a preheating section II arranged sequentially along the conveying direction of carbon-containing green pellets, and is used to dry and preheat the carbon-containing green pellets; A rotary kiln, whose feed end is connected to the discharge end of the chain grate machine, allows the preheated carbon-containing green pellets to undergo a reduction reaction and generate metallized pellets and reducing gas. The waste gas utilization device includes a waste heat utilization component and a waste gas utilization component. The waste heat utilization component is used to sequentially introduce the reducing gas into the preheating section II and the drying section for waste heat utilization. The waste gas utilization component is used to use the reducing gas discharged from the drying section as combustion gas for utilization by the preheating section I and the rotary kiln respectively. A horizontally continuous feeding electric arc furnace includes an electric arc furnace body and a scrap steel preheating section. The electric arc furnace body is connected to the discharge end of the rotary kiln through the scrap steel preheating section. The scrap steel preheating section is used to transport the metallized pellets and scrap steel, and uses the electric arc furnace flue gas generated by the electric arc furnace body and the waste heat of the metallized pellets to preheat the scrap steel. The electric arc furnace body melts the metallized pellets and scrap steel.

[0007] Preferably, the drying section, the preheating section I, and the preheating section II are all equipped with air boxes for guiding gas flow.

[0008] Preferably, the waste heat utilization component includes two hot air ducts, one end of which is connected to the exhaust port of the rotary kiln and the other end of which is connected to the air box on the preheating section II; the other hot air duct is connected to the exhaust port of the preheating section II and the other end of which is connected to the air box on the drying section.

[0009] Preferably, the waste gas utilization component includes a main pipe connected to the exhaust port of the drying section, and the main pipe is connected to two branch pipes via a tee. One of the branch pipes is connected to the air box on the preheating section I, and a combustion furnace is installed on the branch pipe; the other branch pipe is connected to the combustion chamber of the rotary kiln.

[0010] Preferably, the scrap steel preheating section includes a conveying pipe, which forms two channels, upper and lower, through a layered guide baffle. One end of the lower channel is connected to the discharge end of the rotary kiln via a hot conveying channel, and a spiral pushing mechanism is provided in the lower channel for pushing metallized pellets. A scraper conveying mechanism is provided in the upper channel for conveying scrap steel. A scrap steel feeding port is provided at the end of the upper channel near the hot conveying channel. The discharge ends of both the upper and lower channels are connected to the feeding end of the electric furnace body.

[0011] Preferably, a waste heat flue is provided at the bottom of the conveying pipe, and flue gas holes are provided on the bottom wall of the conveying pipe. The diameter of the holes is smaller than the diameter of the metallized pellets. One end of the waste heat flue is closed, and the other end is connected to the flue gas outlet of the rotary kiln. A flue is provided at the top of the conveying pipe.

[0012] The present invention also provides a method for co-producing pellets and electric furnaces, comprising the following steps: Carbon-containing green pellets are fed into the drying section of a chain grate machine, where the residual heat from the reducing gas in the rotary kiln is used to perform preliminary drying. The dried carbon-containing green pellets are sequentially introduced into the preheating stage I and preheating stage II of the chain grate machine. In the preheating stage I, the reducing gas is first preheated by burning the reducing gas through the residual gas utilization component. Then, in the preheating stage II, the reducing gas from the rotary kiln is used for further preheating. The preheated carbon-containing green pellets are introduced into the rotary kiln, where a reduction reaction occurs under high temperature conditions to generate high-temperature metallized pellets; the reducing gas generated by the rotary kiln flows sequentially through the preheating section II and the drying section to preheat and dry the green pellets. The high-temperature metallized pellets generated in the rotary kiln are directly fed into the lower channel of the scrap steel preheating section, while the scrap steel is fed into the upper channel of the scrap steel preheating section, using the residual heat of the high-temperature metallized pellets to preheat the scrap steel. The high-temperature electric furnace flue gas generated during the smelting process of the electric furnace body is introduced into the scrap steel preheating section to preheat the metallized pellets and the scrap steel inside. The metallized pellets and the scrap steel, after being preheated in the scrap steel preheating section, are fed into the electric furnace body for smelting.

[0013] Preferably, in the step of sequentially introducing the dried carbon-containing green pellets into the preheating stage I and preheating stage II of the chain grate, first preheating the reducing gas by burning the residual gas in the preheating stage I, and then further preheating the reducing gas from the rotary kiln in the preheating stage II, the gas discharged from the drying stage is divided into two paths: one path is introduced into the combustion furnace for heating and used for preheating in the preheating stage I, and the other path is introduced into the combustion chamber of the rotary kiln as auxiliary fuel.

[0014] Preferably, in the step of preheating the carbon-containing green pellets into the rotary kiln and undergoing a reduction reaction under high temperature conditions to generate high-temperature metallized pellets; and in the step of the reducing gas generated by the rotary kiln sequentially flowing through the preheating section II and the drying section to preheat and dry the green pellets, the reduction reaction temperature in the rotary kiln is 1100℃-1300℃, and the temperature of the generated metallized pellets is 900℃-1000℃.

[0015] Preferably, in the step of introducing the high-temperature electric furnace flue gas generated during the smelting process of the electric furnace body into the scrap steel preheating section to preheat the metallized pellets and the scrap steel inside, and then discharging the preheated electric furnace flue gas through the flue, the initial temperature of the electric furnace flue gas is 800-1000℃, and the discharge temperature after passing through the scrap steel preheating section is controlled to be 300-400℃.

[0016] Compared with the prior art, the present invention has the following advantages and technical effects: 1. This invention couples the production of metallized pellets by a chain grate machine-rotary kiln with the production of a horizontal continuous feeding electric furnace. After being produced by the rotary kiln, the metallized pellets are directly sent hot into the scrap steel preheating section, avoiding the heat loss caused by the cooling and transfer of metallized pellets in traditional production. This significantly reduces the heating energy consumption of electric furnace smelting and improves the overall production efficiency.

[0017] 2. The reducing gas generated by the rotary kiln is fully utilized and used sequentially for the processing of green pellets in the preheating stage II and the drying stage. At the same time, part of the reducing gas is returned to the rotary kiln as auxiliary fuel, realizing the recycling of reducing gas, reducing energy waste, and lowering fuel consumption.

[0018] 3. The high-temperature flue gas generated by the electric furnace is used to preheat the materials in the scrap steel preheating section, recovering and utilizing a large amount of heat energy in the flue gas, further reducing the overall production energy consumption. At the same time, the preheated materials enter the electric furnace, which can shorten the smelting time and improve smelting efficiency.

[0019] 4. The entire system realizes the coordinated recycling of materials and energy, reduces the direct emission of waste gas and flue gas, reduces environmental pressure, meets the development needs of the steel industry for green and low-carbon transformation, and has both economic and environmental benefits. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 This is a schematic diagram of the structure of a pelletizing-electric furnace co-production system proposed in this invention; The components are: 1. Chain grate machine; 2. Rotary kiln; 3. Horizontal continuous feeding electric furnace; 4. Drying section; 5. Preheating section I; 6. Preheating section II; 7. Scrap steel preheating section; 8. Electric furnace body; 9. Combustion furnace; 10. Hot conveying channel; 11. Blowbox; 12. Temperature control device; 14. Dust removal device; 15. Flue; 16. Carbon-containing green pellets; 17. Metallized pellets; 18. Scrap steel feeding port; 19. Reducing gas; 20. Pellet flue gas; 21. Electric furnace flue gas. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Reference Figure 1 As shown, the present invention provides a pelletizing-electric furnace co-production system, comprising: The chain grate machine 1 includes a drying section 4, a preheating section I 5 and a preheating section II 6 arranged sequentially along the conveying direction of the carbon-containing green pellets 16, for drying and preheating the carbon-containing green pellets 16; The rotary kiln 2 has its feed end connected to the discharge end of the chain grate machine 1, so that the preheated carbon-containing green pellets 16 undergo a reduction reaction to generate metallized pellets 17 and reducing gas 19. The waste gas utilization device includes a waste heat utilization component and a waste gas utilization component. The waste heat utilization component is used to introduce the reducing gas 19 into the preheating section II 6 and the drying section 4 in sequence for waste heat utilization. The waste gas utilization component is used to use the reducing gas 19 discharged from the drying section 4 as a combustion gas for combustion and utilization by the preheating section I 5 and the rotary kiln 2 respectively. The horizontal continuous feeding electric furnace 3 includes an electric furnace body 8 and a scrap steel preheating section 7. The electric furnace body 8 is connected to the discharge end of the rotary kiln 2 through the scrap steel preheating section 7. The scrap steel preheating section 7 is used to transport the metallized pellets 17 and scrap steel, and uses the electric furnace flue gas 21 generated by the electric furnace body 8 and the waste heat of the metallized pellets 17 to preheat the scrap steel. The electric furnace body 8 smelts the metallized pellets 17 and scrap steel.

[0024] Furthermore, air boxes 11 for guiding gas flow are installed on the drying section 4, the preheating section I 5, and the preheating section II 6.

[0025] Furthermore, the waste heat utilization component includes two hot air ducts. One end of the hot air duct is connected to the exhaust port of the rotary kiln 2, and the other end is connected to the air box 11 on the preheating section II 6. The other hot air duct is connected to the exhaust port of the preheating section II 6, and the other end is connected to the air box 11 on the drying section 4.

[0026] In this embodiment, a temperature regulating device 12 is provided between the combustion furnace 9 and the preheating section I 5 to control the temperature of the gas entering the preheating section I 5, specifically 800-900℃; wherein, the temperature regulating device 12 is a commercially available component, and its specific working principle will not be described here.

[0027] Furthermore, the waste gas utilization component includes a main pipe connected to the exhaust port of the drying section 4. The main pipe is connected to two branch pipes via a tee. One branch pipe is connected to the air box 11 on the preheating section 5, and a combustion furnace 9 is installed on the branch pipe. The other branch pipe is connected to the combustion chamber of the rotary kiln 2.

[0028] Furthermore, the scrap steel preheating section 7 includes a conveying pipe. The conveying pipe is divided into two channels, upper and lower, by a layered guide baffle. One end of the lower channel is connected to the discharge end of the rotary kiln 2 through the hot conveying channel 10. A spiral pushing mechanism is provided in the lower channel to push the metallized pellets 17. A scraper conveying mechanism is provided in the upper channel to convey scrap steel. A scrap steel feeding port 18 is provided at the end of the upper channel near the hot conveying channel 10. The discharge ends of both the upper and lower channels are connected to the feeding end of the electric furnace body 8.

[0029] In this embodiment, the spiral pushing mechanism and the scraper conveying mechanism are existing technologies. An insulation layer is provided inside the hot conveying channel 10 to reduce heat loss of the metallized pellets during the conveying process.

[0030] Specifically, the conveying pipeline is equipped with layered flow guide baffles along the material conveying direction. The layered flow guide baffles divide the inside of the conveying pipeline into upper and lower channels. The lower channel is dedicated to the passage of high-temperature metallized pellets 17, and the upper channel is dedicated to the passage of scrap steel. The two channels are independent of each other and do not mix.

[0031] The lower channel is equipped with a high-temperature resistant spiral pushing mechanism to stably convey the high-temperature metallized pellets 17 to the electric furnace body 8. The upper channel is equipped with a scraper conveying mechanism to convey the scrap steel forward along the upper channel. After exiting the rotary kiln 2, the metallized pellets 17 are in a high-temperature state (900-1000℃). During the conveying in the lower channel, heat is continuously released to the scrap steel in the upper channel through heat conduction by the layered guide baffles and radiation heat exchange inside the conveying pipe, so as to achieve the preheating of the upper scrap steel by the lower high-temperature metallized pellets.

[0032] Furthermore, a waste heat flue is provided at the bottom of the conveying pipeline, and flue gas holes are provided on the bottom wall of the conveying pipeline. The diameter of the holes is smaller than the diameter of the metallized pellet 17. One end of the waste heat flue is closed, and the other end is connected to the flue gas outlet of the rotary kiln 2. A flue 15 is provided at the top of the conveying pipeline.

[0033] In this embodiment, a dust removal device 14 is installed on the flue 15 to purify the electric furnace flue gas 21, reduce pollutant emissions, and meet environmental protection requirements. It should be noted that the dust removal device 14 is prior art, and its specific working principle will not be described here.

[0034] The electric furnace flue gas 21 generated by the electric furnace body 8 is introduced into the waste heat flue, and the metallized pellets and scrap steel in the scrap steel preheating section 7 are preheated through the flue gas holes arranged on the bottom wall of the conveying pipe.

[0035] The present invention also provides a method for co-producing pellets and electric furnaces, comprising the following steps: Carbon-containing green pellets 16 are fed into the drying section 4 of the chain grate machine 1, and the carbon-containing green pellets 16 are initially dried using the residual heat of the reducing gas 19 from the rotary kiln 2. The dried carbon-containing green pellets 16 are sequentially introduced into the preheating section I 5 and preheating section II 6 of the chain grate machine 1. First, in the preheating section I 5, the reducing gas 19 is preheated by burning the residual gas utilization component. Then, in the preheating section II 6, the reducing gas 19 from the rotary kiln 2 is used for further preheating. The preheated carbon-containing green pellets 16 are introduced into the rotary kiln 2, where a reduction reaction occurs under high temperature conditions to generate high-temperature metallized pellets 17; the reducing gas 19 generated by the rotary kiln 2 flows sequentially through the preheating section II 6 and the drying section 4 to preheat and dry the green pellets. The high-temperature metallized pellets 17 generated in the rotary kiln 2 are directly fed into the lower channel of the scrap steel preheating section 7, while the scrap steel is fed into the upper channel of the scrap steel preheating section 7, using the residual heat of the high-temperature metallized pellets 17 to preheat the scrap steel. The high-temperature electric furnace flue gas 21 generated during the smelting process of the electric furnace body 8 is introduced into the scrap steel preheating section 7 to preheat the metallized pellets 17 and scrap steel inside. The metallized pellets 17, which have been preheated in the scrap steel preheating section 7, and the scrap steel are fed into the electric furnace body 8 for smelting.

[0036] Furthermore, in the step of sequentially introducing the dried carbon-containing green pellets 16 into the preheating section I 5 and preheating section II 6 of the chain grate machine 1, the gas discharged from the drying section 4 is divided into two paths. One path is introduced into the combustion furnace 9 to raise the temperature and is used for preheating in the preheating section I 5. The other path is introduced into the combustion chamber of the rotary kiln 2 as auxiliary fuel.

[0037] Furthermore, in the process of preheating the carbon-containing green pellets 16 into the rotary kiln 2, a reduction reaction occurs under high temperature conditions to generate high-temperature metallized pellets 17; in the step of preheating and drying the green pellets by the reducing gas 19 generated by the rotary kiln 2 sequentially flowing through the preheating section II 6 and the drying section 4, the reduction reaction temperature in the rotary kiln 2 is 1100℃-1300℃, and the temperature of the generated metallized pellets 17 is 900℃-1000℃.

[0038] Furthermore, in the step of introducing the high-temperature electric furnace flue gas 21 generated during the smelting process of the electric furnace body 8 into the scrap steel preheating section 7 to preheat the metallized pellets 17 and scrap steel inside, and then discharging the preheated electric furnace flue gas 21 through the flue 15, the initial temperature of the electric furnace flue gas 21 is 800-1000℃, and after being heated by the scrap steel preheating section 7, the discharge temperature is controlled to be 300-400℃.

[0039] When using this invention: Carbon-containing green pellets 16 are fed into the drying section 4 of the chain grate machine 1. The reducing gas 19 generated by the rotary kiln 2, with a temperature of about 600-700℃, is used to initially dry the carbon-containing green pellets 16, removing the moisture from the green pellets and preparing them for subsequent preheating and reduction reactions.

[0040] After drying, the green pellets sequentially enter preheating stage I 5 and preheating stage II 6. Preheating stage I 5 uses high-temperature gas from combustion in the combustion furnace 9, with a temperature of approximately 800-900℃, to preheat the carbon-containing green pellets 16, raising their temperature to 400-500℃. Preheating stage II 6 uses reducing gas 19 discharged from the rotary kiln 2 to further preheat the green pellets, raising their temperature to 700-800℃, thereby improving the efficiency of subsequent reduction reactions.

[0041] The preheated carbon-containing green pellets 16 enter the rotary kiln 2 and undergo a reduction reaction at a high temperature of 1100-1300℃ to generate high-temperature metallized pellets 17 at a temperature of 900-1000℃. The reducing gas 19 generated by the rotary kiln 2, with a temperature of about 600-700℃, flows sequentially through the preheating section II 6 and the lower layer of the drying section 4 to dry the green pellets before being discharged from the upper layer of the drying section 4.

[0042] The gas discharged from the upper layer of the drying section 4 is divided into two paths. One path enters the combustion furnace 9 and is heated to 800-900℃ before being passed into the preheating section I 5 to preheat the carbon-containing green pellets 16, and is finally discharged as pellet flue gas 20. The other path enters the combustion chamber of the rotary kiln 2 as auxiliary fuel to heat the rotary kiln 2, supplement the heat demand of the rotary kiln 2, and reduce the consumption of the main fuel.

[0043] The high-temperature metallized pellets 17 generated by the rotary kiln 2 are directly fed into the lower layer of the scrap steel preheating section 7 of the horizontal continuous feeding electric furnace 3 through the hot conveying channel 10. At the same time, the scrap steel is fed into the upper layer of the scrap steel preheating section 7, and the scrap steel is preheated using the residual heat of the metallized pellets 17.

[0044] The high-temperature electric furnace flue gas 21 generated during the smelting process of the electric furnace body 8 has an initial temperature of 800-1000℃. It is introduced into the scrap steel preheating section 7 to preheat the metallized pellets 17 and scrap steel in the scrap steel preheating section 7, raising the material temperature to 500-600℃. After cooling, the electric furnace flue gas 21 has a temperature of 300-400℃. It is then discharged after being purified by the dust removal device 14, reducing pollutant emissions.

[0045] After preheating, the metallized pellets 17 and scrap steel are fed into the electric furnace body 8 through a screw conveyor and a scraper conveyor, respectively, for smelting operations, thus completing the pellet-electric furnace co-production process.

[0046] This invention achieves material heat delivery and energy recycling by co-producing pellets with electric arc furnace smelting. Compared with traditional production methods, it can reduce overall production energy consumption by 15%-20%, shorten electric arc furnace smelting time by 10%-15%, and reduce waste gas and flue gas emissions. It is both economical and environmentally friendly, and provides an innovative solution for the green and low-carbon transformation of the steel industry.

[0047] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0048] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A pelletizing-electric furnace co-production system, characterized in that, include: The chain grate machine (1) includes a drying section (4), a preheating section I (5) and a preheating section II (6) arranged sequentially along the conveying direction of the carbon-containing green pellets (16), for drying and preheating the carbon-containing green pellets (16); The rotary kiln (2) has its feed end connected to the discharge end of the chain grate machine (1), so that the preheated carbon-containing green pellets (16) undergo a reduction reaction and generate metallized pellets (17) and reducing gas (19). The waste gas utilization device includes a waste heat utilization component and a waste gas utilization component. The waste heat utilization component is used to introduce the reducing gas (19) into the preheating section II (6) and the drying section (4) in sequence for waste heat utilization. The waste gas utilization component is used to use the reducing gas (19) discharged from the drying section (4) as a combustion gas for combustion and utilization by the preheating section I (5) and the rotary kiln (2) respectively. The horizontal continuous feeding electric furnace (3) includes an electric furnace body (8) and a scrap steel preheating section (7). The electric furnace body (8) is connected to the discharge end of the rotary kiln (2) through the scrap steel preheating section (7). The scrap steel preheating section (7) is used to transport the metallized pellets (17) and scrap steel, and uses the electric furnace flue gas (21) generated by the electric furnace body (8) and the residual heat of the metallized pellets (17) to preheat the scrap steel. The electric furnace body (8) melts the metallized pellets (17) and scrap steel.

2. The pelletizing-electric furnace co-production system according to claim 1, characterized in that, Each of the drying section (4), the preheating section I (5), and the preheating section II (6) is equipped with a blower (11) for guiding gas flow.

3. The pelletizing-electric furnace co-production system according to claim 2, characterized in that, The waste heat utilization component includes two hot air ducts. One end of the hot air duct is connected to the exhaust port of the rotary kiln (2), and the other end is connected to the air box (11) on the preheating section II (6). The other hot air duct is connected to the exhaust port of the preheating section II (6) at one end, and the other end is connected to the air box (11) on the drying section (4).

4. The pelletizing-electric furnace co-production system and method according to claim 2, characterized in that, The waste gas utilization component includes a main pipe connected to the exhaust port of the drying section (4). The main pipe is connected to two branch pipes via a tee. One of the branch pipes is connected to the air box (11) on the preheating section (5), and a combustion furnace (9) is installed on the branch pipe. The other branch pipe is connected to the combustion chamber of the rotary kiln (2).

5. The pelletizing-electric furnace co-production system according to claim 4, characterized in that, The scrap steel preheating section (7) includes a conveying pipe. The conveying pipe is divided into two channels, upper and lower, by a layered guide baffle. One end of the lower channel is connected to the discharge end of the rotary kiln (2) through a hot conveying channel (10). A spiral pushing mechanism is provided in the lower channel to push metallized pellets (17). A scraper conveying mechanism is provided in the upper channel to convey scrap steel. A scrap steel feeding port (18) is provided at the end of the upper channel near the hot conveying channel (10). The discharge ends of both the upper and lower channels are connected to the feeding end of the electric furnace body (8).

6. The pelletizing-electric furnace co-production system according to claim 5, characterized in that, The bottom of the conveying pipe is provided with a waste heat flue, and the bottom wall of the conveying pipe is provided with flue gas holes with a diameter smaller than that of the metallized pellet (17). One end of the waste heat flue is closed, and the other end is connected to the flue gas outlet of the rotary kiln (2). The upper part of the conveying pipe is provided with a flue (15).

7. A method for co-producing pellets and electric furnaces, based on the pellet-electric furnace co-production system according to any one of claims 1-6, characterized in that, Includes the following steps: Carbon-containing green pellets (16) are fed into the drying section (4) of the chain grate machine (1) and the carbon-containing green pellets (16) are preliminarily dried using the residual heat of the reducing gas (19) from the rotary kiln (2). The dried carbon-containing green pellets (16) are sequentially introduced into the preheating section I (5) and preheating section II (6) of the chain grate machine (1). First, the reducing gas (19) is preheated by burning the residual gas utilization component in the preheating section I (5), and then the reducing gas (19) from the rotary kiln (2) is used for further preheating in the preheating section II (6). The preheated carbon-containing green pellets (16) are introduced into the rotary kiln (2) and undergo a reduction reaction under high temperature conditions to generate high-temperature metallized pellets (17); the reducing gas (19) generated by the rotary kiln (2) flows sequentially through the preheating section II (6) and the drying section (4) to preheat and dry the green pellets; The high-temperature metallized pellets (17) generated in the rotary kiln (2) are directly fed into the lower channel of the scrap steel preheating section (7), while the scrap steel is fed into the upper channel of the scrap steel preheating section (7) to preheat the scrap steel using the residual heat of the high-temperature metallized pellets (17). The high-temperature electric furnace flue gas (21) generated during the smelting process of the electric furnace body (8) is introduced into the scrap steel preheating section (7) to preheat the metallized pellets (17) and the scrap steel inside. The metallized pellets (17) and the scrap steel, after being preheated in the scrap steel preheating section (7), are fed into the electric furnace body (8) for smelting.

8. The pelletizing-electric furnace co-production method according to claim 7, characterized in that, In the step of sequentially introducing the dried carbon-containing green pellets (16) into the preheating section I (5) and preheating section II (6) of the chain grate machine (1), the reducing gas (19) is first preheated in the preheating section I (5) by burning the reducing gas (19) through the residual gas utilization component, and then further preheated in the preheating section II (6) by using the reducing gas (19) from the rotary kiln (2). The gas discharged from the drying section (4) is divided into two paths. One path is introduced into the combustion furnace (9) to be heated and used for preheating in the preheating section I (5), and the other path is introduced into the combustion chamber of the rotary kiln (2) as auxiliary fuel.

9. The pelletizing-electric furnace co-production method according to claim 7, characterized in that, In the process of preheating the carbon-containing green pellets (16) into the rotary kiln (2), a reduction reaction occurs under high temperature conditions to generate high-temperature metallized pellets (17); in the step of the reducing gas (19) generated by the rotary kiln (2) flowing sequentially through the preheating section II (6) and the drying section (4) to preheat and dry the green pellets, the reduction reaction temperature in the rotary kiln (2) is 1100℃-1300℃, and the temperature of the generated metallized pellets (17) is 900℃-1000℃.

10. The pelletizing-electric furnace co-production method according to claim 7, characterized in that, In the step of introducing the high-temperature electric furnace flue gas (21) generated during the smelting process of the electric furnace body (8) into the scrap steel preheating section (7) to preheat the metallized pellets (17) and the scrap steel inside, and then discharging the preheated electric furnace flue gas (21) through the flue (15), the initial temperature of the electric furnace flue gas (21) is 800℃-1000℃, and after being heated by the scrap steel preheating section (7), the discharge temperature is controlled to be 300℃-400℃.

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