Steel slag sensible heat recovery system and recovery method

Abstract

The application discloses a steel slag sensible heat recovery system and a recovery method. The system comprises a first chain grate, a second chain grate, a third chain grate, a first air supply device, a second air supply device, a first sealing cover and a second sealing cover. The first chain grate is provided with a high-temperature liquid slag tank at the feeding end, and the first chain grate outputs medium-temperature steel slag at the discharging end. The second chain grate is located above the first chain grate, the feeding end of the second chain grate is provided with a scrap steel tank, and the discharging end of the second chain grate is provided with a scrap steel receiving tank. The feeding end of the third chain grate is communicated with the discharging end of the first chain grate, and the discharging end of the third chain grate is provided with a cooled steel slag tank. The first sealing cover is sequentially arranged on the second chain grate and the first chain grate. The second sealing cover is arranged on the third chain grate. The application utilizes the steel slag heat to realize the preheating of scrap steel and the recovery of steel slag sensible heat, thereby realizing the efficient utilization of energy.

Description

Technical Field

[0001] This application belongs to the field of iron and steel metallurgy technology, specifically relating to a steel slag sensible heat recovery system and recovery method. Background Technology

[0002] Steel slag is a major byproduct of iron and steel smelting, with a furnace exit temperature as high as 1400℃–1650℃. Each ton of steel slag contains approximately 2000 MJ of heat, equivalent to 61 kg of standard coal, making it a high-quality waste heat resource with significant development potential. Efficiently recovering the sensible heat of steel slag is crucial for reducing energy consumption, carbon emissions, and contributing to dual-carbon goals. However, steel slag sensible heat recovery has not yet been implemented in engineering applications. Existing technologies include wet water quenching, which has extremely low recovery rates and consumes a large amount of water, causing severe pollution; while dry recovery methods offer environmental advantages, they suffer from problems such as the inability to eliminate free calcium oxide, large equipment size, high energy consumption, and slag adhesion and clogging.

[0003] Steel slag has low thermal conductivity, large viscosity fluctuations, poor fluidity, and undergoes a phase change during cooling, and is highly corrosive, making the design of heat exchange systems very difficult. Summary of the Invention

[0004] To address the current technical problem of poor sensible heat recovery efficiency of steel slag, this application provides a steel slag sensible heat recovery system and recovery method.

[0005] In a first aspect of this application, a steel slag sensible heat recovery system is provided, comprising: The first chain grate machine has a high-temperature liquid slag tank at its feed end and outputs medium-temperature steel slag at its discharge end. The second chain grate machine is located above the first chain grate machine. The feed end of the second chain grate machine is equipped with a scrap steel trough, and the discharge end of the second chain grate machine is equipped with a scrap steel receiving tank. The third chain grate machine has its inlet end connected to the outlet end of the first chain grate machine, and its outlet end is equipped with a cooling slag tank. A first air supply device, the first air supply device being used to deliver cold air; The second air supply device is used to deliver cold air. A first sealing cover is sequentially installed over the second chain grate machine and the first chain grate machine. The first sealing cover has a first air outlet for communication with the boiler and a first air inlet for communication with the first air supply device; and... The second sealing cover is provided on the third chain grate machine. The second sealing cover is provided with a second air outlet for communicating with the boiler and a second air outlet for communicating with the second air supply device.

[0006] In some embodiments, the first chain grate machine, the second chain grate machine, and the third chain grate machine are all made of high-temperature resistant materials.

[0007] In some embodiments, the high temperature resistance of the first chain grate machine is greater than 1300°C; The second chain grate machine has a high temperature resistance of 1200℃~1300℃; The third chain grate machine has a high temperature resistance of 1000℃~1200℃.

[0008] In some embodiments, the steel slag sensible heat recovery system further includes a first air outlet duct and a second air outlet duct; The first air outlet of the first sealing cover is connected to the boiler through the first air outlet pipe; The second air outlet of the second sealing cover is connected to the boiler through the second air outlet duct.

[0009] In some embodiments, the second air outlet duct is connected to the first air outlet duct, and the steel slag sensible heat recovery system further includes a first check valve provided in the first air outlet duct and a second check valve provided in the second air outlet duct. The first check valve is located upstream of the connection point between the first air outlet duct and the second air outlet duct; The second check valve is located upstream of the connection point between the first air outlet duct and the second air outlet duct.

[0010] In some embodiments, the feed end of the first chain grate is also provided with a bottom trough, which is used to hold the steel slag particles from the discharge end of the third chain grate.

[0011] In some embodiments, the first air supply device includes a first blower, a first air duct, and a first air distributor; the inlet end of the first blower is connected to a cold air source, and the outlet end of the first blower is connected to the first air distributor through the first air duct. The first air distributor includes a first distributor body and a plurality of first nozzles disposed on the first distributor body. The inner diameter of the first nozzles gradually increases from the first blower end to the first chain grate end. The first nozzles are connected to and communicate with the first sealing cover.

[0012] In some embodiments, the second air supply device includes a second blower, a second air duct, and a second air distributor; the inlet end of the second blower is connected to a cold air source, and the outlet end of the second blower is connected to the second air distributor through the second air duct. The second air distributor includes a second distributor body and a plurality of second nozzles disposed on the second distributor body. The inner diameter of the second nozzles gradually increases from the second blower end to the third chain grate end. The second nozzles are connected to and communicate with the second sealing cover.

[0013] In some embodiments, a crusher is also provided between the discharge end of the first chain grate and the feed end of the third chain grate; The steel slag sensible heat recovery system also includes a third sealing cover, which is installed over the crusher. In a second aspect of this application, a recovery method based on the above-described steel slag sensible heat recovery system is provided, comprising the following steps: The system startup steps are as follows: the first air supply device forms a first heat exchange airflow sequentially through the first chain grate machine, the second chain grate machine, and the boiler; the second air supply device forms a second heat exchange airflow sequentially through the third chain grate machine and the boiler. Wherein, the first heat exchange airflow exchanges heat with the high-temperature liquid steel slag on the first chain grate machine to cool the high-temperature liquid steel slag to 850℃~900℃, and the temperature of the first heat exchange airflow after exchanging heat with the high-temperature liquid steel slag is 1000℃~1100℃. The first heat exchange airflow exchanges heat with the scrap steel on the second chain grate machine to preheat the scrap steel to 700℃~800℃, and the temperature of the first heat exchange airflow after exchanging heat with the scrap steel is 800℃~900℃; The second heat exchange airflow exchanges heat with the steel slag conveyed by the third chain grate machine to cool the steel slag to below 100°C. The temperature of the second heat exchange airflow after exchanging heat with the steel slag is 450°C to 500°C.

[0014] A steel slag sensible heat recovery system and method are provided according to one or more embodiments of this application. The steel slag sensible heat recovery system includes a first chain grate, a second chain grate, a third chain grate, a first air supply device, a second air supply device, a first sealing cover, and a second sealing cover. The first chain grate has a high-temperature liquid slag tank at its feed end and outputs medium-temperature steel slag at its discharge end. The second chain grate is located above the first chain grate, with a scrap steel trough at its feed end and a scrap steel receiving tank at its discharge end. The third chain grate's feed end is connected to the first chain grate's discharge end. The third chain grate is connected to a cooling slag tank at its discharge end; a first air supply device is used to deliver cold air; a second air supply device is used to deliver cold air; a first sealing cover is sequentially installed over the second and first chain grate machines, and the first sealing cover has a first air outlet for connection to the boiler and a first air inlet for connection to the first air supply device; a second sealing cover is installed over the third chain grate machine, and the second sealing cover has a second air outlet for connection to the boiler and a second air outlet for connection to the second air supply device. This application utilizes the heat of steel slag to achieve both preheating of scrap steel and recovery of sensible heat from the steel slag, thereby achieving efficient energy utilization. Attached Figure Description

[0015] Figure 1 A schematic diagram of the sensible heat recovery system for steel slag is shown in one or more embodiments of this application.

[0016] Figure 2 A flowchart of a recovery method for a steel slag sensible heat recovery system according to one or more embodiments of this application is shown.

[0017] Explanation of reference numerals in the attached diagram: 10-Steel slag sensible heat recovery system; 100-First chain grate machine; 110-High-temperature liquid slag tank; 111-High-temperature liquid slag; 120-Bottom trough; 121-Steel slag particles; 122-Medium-temperature steel slag; 200-Second chain grate machine; 210-Scrap steel trough; 211-Scrap steel; 220-Scrap steel receiving tank; 300-Third chain grate machine; 310-Cooling steel slag tank; 311-Cooling steel slag particles; 400-First air supply device; 410-First blower; 420-First blower duct; 430-First... Air distributor, 431-first distributor body, 432-first nozzle, 500-second air supply device, 510-second blower, 520-second blower duct, 530-second air distributor, 531-second distributor body, 532-second nozzle, 600-first sealing cover, 610-first outlet duct, 620-first check valve, 700-second sealing cover, 710-second outlet duct, 720-second check valve, 800-crusher, 900-third sealing cover, 20-boiler. Detailed Implementation

[0018] To enable those skilled in the art to more clearly understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] In waste heat recovery systems, high-temperature conditions place stringent requirements on equipment materials. Prolonged exposure to rapid temperature changes above 1400℃ can easily lead to oxidation, wear, and corrosion. Improving the high-temperature resistance and corrosion resistance of equipment is a key bottleneck for engineering applications. Furthermore, existing methods for preheating scrap steel mostly employ electric heating or the addition of carbon powder, resulting in high electricity consumption and significant carbon emissions. Therefore, to address these issues, this application provides a steel slag sensible heat recovery system and method.

[0020] Please see Figure 1 According to a first aspect of this application, a steel slag sensible heat recovery system 10 is provided, including a first chain grate 100, a second chain grate 200, a third chain grate 300, a first air supply device 400, a second air supply device 500, a first sealing cover 600, and a second sealing cover 700. The first chain grate 100 has a high-temperature liquid slag tank 110 at its feed end and outputs medium-temperature steel slag 122 at its discharge end. The second chain grate 200 is located above the first chain grate 100, with a scrap steel trough 210 at its feed end and a scrap steel receiving tank 220 at its discharge end. The third chain grate 300... The feed end is connected to the discharge end of the first chain grate 100, and the discharge end of the third chain grate 300 is provided with a cooling slag tank 310; the first air supply device 400 is used to supply cold air; the second air supply device 500 is used to supply cold air; the first sealing cover 600 is sequentially installed on the second chain grate 200 and the first chain grate 100, and the first sealing cover 600 is provided with a first air outlet for communication with the boiler 20 and a first air inlet for communication with the first air supply device 400; the second sealing cover 700 is installed on the third chain grate 300, and the second sealing cover 700 is provided with a second air outlet for communication with the boiler 20 and a second air outlet for communication with the second air supply device 500.

[0021] The first chain grate 100, the second chain grate 200, and the third chain grate 300 are each driven by a transmission device. The second chain grate 200 is positioned above the first chain grate 100 and can be staggered to facilitate the placement of the high-temperature liquid slag tank 110 at the feed end of the first chain grate 100 and the scrap steel trough 210 at the feed end of the second chain grate 200. The first chain grate 100 and the second chain grate 200 are enclosed by the same first sealing cover 600. The hot air passing through the first chain grate 100 can directly enter the second chain grate 200. The first chain grate 100 is used to cool the high-temperature liquid steel slag, and the hot air after heat exchange with the high-temperature liquid steel slag is directly used to preheat the scrap steel 211 on the second chain grate 200. The sensible heat of the steel slag is used to preheat the scrap steel 211, and the heat exchange is carried out through the heat of the high-temperature liquid steel slag, thus reducing energy consumption. The high-temperature steel slag cooled by the first chain grate machine 100 enters the third chain grate machine 300, where it is cooled again by the second air supply device 500 to obtain cooled steel slag particles 121.

[0022] The high-temperature air from the first grate machine 100 and the second grate machine 200 is input into the boiler 20 through the first sealing cover 600, and the medium-temperature air from the third grate machine 300 is input into the boiler 20 through the second sealing cover 700. The two streams of air with different temperatures are mixed and then enter the boiler 20 for further heat recovery.

[0023] Therefore, this application utilizes the heat of steel slag to both preheat scrap steel 211 and recover the sensible heat of steel slag, thereby achieving efficient energy utilization.

[0024] In some embodiments, the first chain grate machine 100, the second chain grate machine 200, and the third chain grate machine 300 are all made of high-temperature resistant materials. The grate plates, chains, and side plates of the first chain grate machine 100 are all made of high-temperature resistant materials; the grate plates, chains, and side plates of the second chain grate machine 200 are all made of high-temperature resistant materials; and the grate plates, chains, and side plates of the third chain grate machine 300 are all made of high-temperature resistant materials. This allows the first chain grate machine 100, the second chain grate machine 200, and the third chain grate machine 300 to maintain structural stability and mechanical strength under high-temperature process environments, preventing high-temperature softening and oxidation burn-off, thereby extending the service life of the equipment and ensuring continuous and stable process operation.

[0025] In some embodiments, the high-temperature resistance of the first chain grate 100, the second chain grate 200, and the third chain grate 300 decreases sequentially. That is, the high-temperature resistance of the first chain grate 100 is greater than that of the second chain grate 200, and the high-temperature resistance of the second chain grate 200 is greater than that of the third chain grate 300. In actual processes, the temperature of the material conveyed by the first chain grate 100 is higher than that of the material conveyed by the second chain grate 200, and the temperature of the material conveyed by the second chain grate 200 is higher than that of the material conveyed by the third chain grate 300. Therefore, under the premise of ensuring the normal operation of the process, the equipment manufacturing cost of the first chain grate machine 100, the second chain grate machine 200 and the third chain grate machine 300 can be reduced. The first chain grate machine 100 is made of high-grade heat-resistant material to ensure structural stability. The second chain grate machine 200 can be made of a material that is slightly lower than that of the first chain grate machine 100. The third chain grate machine 300 is made of a material that is slightly lower than that of the second chain grate machine 200.

[0026] In some embodiments, the first chain grate 100 has a high temperature resistance greater than 1300℃; the first chain grate 100 is made of ultra-high temperature heat-resistant material, which has a high temperature resistance greater than 1300℃, and is suitable for areas that directly contact high-temperature liquid slag 111. It can effectively resist softening deformation and oxidation burn-off under extreme high temperature environment, and ensure the structural integrity and long-term stable operation of the equipment in the highest temperature range.

[0027] In some embodiments, the high temperature resistance of the second chain grate 200 is 1200℃~1300℃; the second chain grate 200 is made of medium and high temperature heat-resistant material, and its high temperature resistance is 1200℃~1300℃. The second chain grate 200 is mainly used for heat exchange of scrap steel 211, that is, it can exchange the high temperature air above the first chain grate 100. Therefore, the high temperature resistance of the second chain grate 200 can be slightly lower than that of the first chain grate 100. While ensuring reliability, it can reduce costs and at the same time ensure the temperature resistance performance of the second chain grate 200.

[0028] In some embodiments, the high-temperature resistance of the third chain grate 300 is 1000℃~1200℃. The third chain grate 300 is made of standard heat-resistant material with a high-temperature resistance of 1000℃~1200℃. The temperature of the material conveyed by the third chain grate 300 is lower than that of the first chain grate 100 and the second chain grate 200. Therefore, the high-temperature resistance of the third chain grate 300 can be slightly lower than that of the second chain grate 200. This reduces costs while ensuring reliability, and simultaneously guarantees the temperature resistance performance of the third chain grate 300.

[0029] Therefore, the high temperature resistance of the first chain grate machine 100, the second chain grate machine 200, and the third chain grate machine 300 can be reduced in a stepwise manner. This ensures the safe and stable operation of each section of equipment under its corresponding working conditions, avoids resource waste caused by using the same material for the entire system, thereby improving the service life of the system and reducing costs.

[0030] In some embodiments, the steel slag sensible heat recovery system 10 further includes a first air outlet duct 610 and a second air outlet duct 710; the first air outlet of the first sealing cover 600 is connected to the boiler 20 through the first air outlet duct 610; the second air outlet of the second sealing cover 700 is connected to the boiler 20 through the second air outlet duct 710. The first sealing cover 600 can collect the heat from the first grate machine 100 and the second grate machine 200, and then transport it to the boiler 20 through the first air outlet duct 610; the second sealing cover 700 can collect the heat from the third grate machine 300, and then transport it to the boiler 20 through the second air outlet duct 710. The first air outlet duct 610 and the second air outlet duct 710 are independent of each other and do not interfere with each other. By receiving the waste heat from both sources, the boiler 20 converts the sensible heat into steam or electricity, thereby significantly improving the sensible heat recovery efficiency of the steel slag, reducing the system's dependence on external energy, and avoiding thermal pollution and energy waste caused by the direct emission of high-temperature exhaust gas.

[0031] In some embodiments, the second exhaust duct 710 is connected to the first exhaust duct 610. The steel slag sensible heat recovery system 10 further includes a first check valve 620 located in the first exhaust duct and a second check valve 720 located in the second exhaust duct. The first check valve 620 is located upstream of the connection between the first and second exhaust ducts. The second check valve 720 is located upstream of the connection between the first and second exhaust ducts. This achieves the convergence and unidirectional isolation protection of the two waste heat exhaust gases. After the first air outlet duct 610 and the second air outlet duct 710 are connected downstream, they form a unified hot air channel that enters the boiler 20, ensuring the unidirectional flow of the two exhaust gases and ensuring that the two waste heat exhaust gases always maintain unidirectional flow during the convergence process, thus ensuring the continuous and efficient operation of the steel slag sensible heat recovery system 10.

[0032] In some embodiments, the feed end of the first chain grate 100 is further provided with a bottom material trough 120, which is used to hold the steel slag particles 121 from the discharge end of the third chain grate 300. That is, the bottom material trough 120 is laid above the inlet of the first chain grate 100, and the steel slag particles 121 in the bottom material trough 120 are first laid on the first chain grate 100. Then, high-temperature liquid steel slag is evenly poured on top of the steel slag particles 121. Laying the steel slag particles 121 on the first chain grate 100 before pouring the high-temperature liquid steel slag can prevent the high-temperature liquid steel slag from sticking to the first chain grate 100. Then, the high-temperature liquid steel slag is cooled by the cold air from the first air supply device 400 to ensure the smooth operation of subsequent processes.

[0033] In some embodiments, the first air supply device 400 includes a first blower 410, a first air duct 420, and a first air distributor 430. The inlet end of the first blower 410 is connected to a cold air source, and the outlet end of the first blower 410 is connected to the first air distributor 430 through the first air duct 420. The first air distributor 430 includes a first distributor body 431 and a plurality of first nozzles 432 disposed on the first distributor body 431. The inner diameter of the first nozzles 432 gradually increases from the end of the first blower 410 to the end of the first chain grate machine 100. The first nozzles 432 are connected to and communicate with the first sealing cover 600. The airflow from the first nozzles 432 enters the first chain grate machine 100 from the end of the first blower 410 through the first sealing cover 600. When the airflow enters the larger cross-section from the smaller cross-section, the flow velocity decreases, and part of the dynamic pressure is converted into static pressure. When the airflow is ejected from the outlet of the first nozzles 432, the velocity is more uniform and gentler, and turbulence or eddies are less likely to occur. The change in the inner diameter of the first nozzle 432 achieves uniform airflow distribution and pressure compensation. The high-pressure airflow generated by the first blower 410 enters the first blower distributor 430 through the first blower pipe 420. Through the gradient design of the inner diameter, the airflow distribution of each first blower outlet tends to be balanced, ensuring uniform airflow distribution in the bottom blower area of ​​the first grate machine 100. This optimizes the cooling effect of the high-temperature liquid steel slag on the first grate machine 100, improves the sensible heat recovery efficiency, and prevents uneven material cooling or local overheating of equipment due to insufficient local airflow.

[0034] In some embodiments, the second air supply device 500 includes a second blower 510, a second blower duct 520, and a second blower distributor 530. The inlet end of the second blower 510 is connected to a cold air source, and the outlet end of the second blower 510 is connected to the second blower distributor 530 through the second blower duct 520. The second blower distributor 530 includes a second distributor body 531 and a plurality of second nozzles 532 disposed on the second distributor body 531. The inner diameter of the second nozzles 532 gradually increases from the end of the second blower 510 to the end of the third chain grate machine 300. The second nozzles 532 are connected to and communicate with the second sealing cover 700. The airflow from the second blower 510 enters the third chain grate machine 300 through the second sealing cover 700. When the airflow enters the larger cross-section from the smaller cross-section, the flow velocity decreases, and part of the dynamic pressure is converted into static pressure. When the airflow is ejected from the outlet of the second nozzles 532, the velocity is more uniform and gentler, and turbulence or eddies are less likely to occur. The change in the inner diameter of the second nozzle 532 achieves uniform airflow distribution and pressure compensation. The high-pressure airflow generated by the second blower 510 enters the second blower distributor 530 through the second blower duct 520. Through the gradient design of the inner diameter, the airflow distribution of each second blower outlet tends to be balanced, ensuring uniform airflow distribution in the bottom blower area of ​​the third chain grate 300. This optimizes the cooling effect of high-temperature steel slag on the third chain grate 300, improves sensible heat recovery efficiency, and prevents uneven material cooling or local overheating of equipment due to insufficient local airflow.

[0035] In some embodiments, a crusher 800 is further provided between the discharge end of the first chain grate 100 and the feed end of the third chain grate 300. By setting the crusher 800 between the discharge end of the first chain grate 100 and the feed end of the third chain grate 300, the high-temperature steel slag output from the discharge end of the first chain grate 100 can be crushed by the crusher 800 to meet the process particle size requirements of the feed end of the third chain grate 300, ensuring the uniformity and heat transfer efficiency of subsequent processing stages. In some embodiments, the crusher 800 can be a double-roll crusher 800. The third chain grate 300 is located below the tail end of the first chain grate 100. The tail discharge of the first chain grate 100 outputs steel slag with a temperature of 850℃~900℃, which is crushed to 3mm~4mm by the double-roll crusher 800 and then fed onto the third chain grate 300 for cooling.

[0036] In some embodiments, the steel slag sensible heat recovery system 10 further includes a third sealing cover 900, which is installed over the crusher 800. Since the steel slag output from the first grate 100 has a high temperature, to avoid heat loss, the third sealing cover 900 on the crusher 800 not only encloses the high-temperature dust and heat radiation during the crushing process within the cover, preventing heat loss and environmental pollution caused by the escape of high-temperature flue gas, but also collects waste heat and exhaust gas within the crusher 800 area and integrates it into the second sealing cover 700, thereby improving the overall system's heat recovery rate and improving the environment.

[0037] In some embodiments, the first sealing cover 600, the third sealing cover 900, and the second sealing cover 700 are connected in sequence and communicate with each other. That is, the first sealing cover 600 covers the first chain grate machine 100 and the second chain grate machine 200. The first sealing cover 600, the second sealing cover 700, and the third sealing cover 900 all have openings at the material input end and the material output end to ensure normal material conveying.

[0038] In some embodiments, the first sealing cover 600, the third sealing cover 900, and the second sealing cover 700 can be connected by welding. Welding ensures airtightness, overall rigidity, and structural strength.

[0039] In the second aspect of this application, as Figure 2 As shown, a recovery method based on the above-described steel slag sensible heat recovery system 10 is provided, comprising the following steps: S100: System startup steps, the first air supply device 400 forms a first heat exchange airflow sequentially through the first chain grate machine 100, the second chain grate machine 200 and the boiler 20, and the second air supply device 500 forms a second heat exchange airflow sequentially through the third chain grate machine 300 and the boiler 20. Understandably, in the startup system of the steel slag sensible heat recovery system 10, the first air supply device 400 is configured to form a first heat exchange airflow that flows sequentially through the first grate 100, the second grate 200, and the boiler 20. Simultaneously, the second air supply device 500 is configured to form a second heat exchange airflow that flows sequentially through the third grate 300 and the boiler 20. The first heat exchange airflow enters the boiler 20 after passing through the first grate 100 and the second grate 200, while the second heat exchange airflow enters the boiler 20 after passing through the third grate 300. The first and second heat exchange airflows participate in heat exchange independently or in combination within the boiler 20. During startup, the system can establish heat exchange airflows in a predetermined sequence, thereby providing a transport path for heat transfer between the first grate 100, the second grate 200, the third grate 300, and the boiler 20.

[0040] S200: The first heat exchange airflow exchanges heat with the high-temperature liquid steel slag on the first chain grate machine 100 to cool the high-temperature liquid steel slag to 850℃~900℃, and the temperature of the first heat exchange airflow after exchanging heat with the high-temperature liquid steel slag is 1000℃~1100℃. Understandably, the first heat exchange airflow exchanges heat with the high-temperature liquid steel slag on the first chain grate 100 to cool the slag to 850℃~900℃; simultaneously, the temperature of the first heat exchange airflow rises to 1000℃~1100℃ after completing the heat exchange with the slag. Through this heat exchange process, on the one hand, the high-temperature liquid steel slag is rapidly cooled, changing from a liquid to a solid or semi-solid state, facilitating subsequent transportation and processing; on the other hand, the first heat exchange airflow itself is heated during the cooling of the steel slag, forming a heat exchange airflow with a high temperature of 1000℃~1100℃, which can be used for subsequent heat energy recovery or fed into equipment such as boiler 20 for reuse. Thus, this process achieves effective recovery and transfer of high-temperature heat source while cooling the steel slag, improving the overall thermal utilization efficiency of the system.

[0041] S300: The first heat exchange airflow exchanges heat with the scrap steel 211 on the second chain grate 200 to preheat the scrap steel 211 to 700℃~800℃. The temperature of the first heat exchange airflow after exchanging heat with the scrap steel 211 is 800℃~900℃. Understandably, the first heat exchange airflow exchanges heat with the scrap steel 211 on the second grate 200 to preheat the scrap steel 211 to 700℃~800℃; simultaneously, the temperature of the first heat exchange airflow drops to 800℃~900℃ after completing the heat exchange with the scrap steel 211. Through this heat exchange process, on the one hand, the first heat exchange airflow, which still has a relatively high temperature after being cooled by the first grate 100, preheats the scrap steel 211, bringing it to a preheating temperature of 700℃~800℃ before it enters the furnace, thereby shortening the melting time of the scrap steel 211 in subsequent smelting equipment and reducing energy consumption; on the other hand, the first heat exchange airflow releases some heat during the preheating process of the scrap steel 211, and its temperature drops accordingly from 1000℃~1100℃ to 800℃~900℃, which can then be further sent to equipment such as boiler 20 for waste heat recovery. Thus, while preheating scrap steel 211, the process also achieves the cascade utilization of the first heat exchange airflow, forming heat matching between multiple stages such as cooling steel slag, preheating scrap steel 211, and waste heat power generation, thereby improving the overall energy utilization efficiency of the system.

[0042] S400: The second heat exchange airflow exchanges heat with the steel slag conveyed by the third chain grate machine 300 to cool the steel slag to below 100°C. The temperature of the second heat exchange airflow after exchanging heat with the steel slag is 450°C~500°C.

[0043] Understandably, the second heat exchange airflow exchanges heat with the steel slag on the third grate 300 to cool the slag to below 100°C. Simultaneously, the temperature of the second heat exchange airflow after heat exchange with the steel slag rises to 450°C–500°C. Through this heat exchange process, on the one hand, the second heat exchange airflow forces the steel slag conveyed by the third grate 300 to cool it to below 100°C, achieving rapid quenching and stabilization of the steel slag, facilitating subsequent transportation, storage, or resource utilization. On the other hand, the second heat exchange airflow absorbs a large amount of heat during the cooling process, heating itself to 450°C–500°C, forming a usable medium-temperature heat exchange airflow that can be further fed into waste heat recovery equipment such as boiler 20 for power generation or heating. Therefore, this process achieves deep cooling of the steel slag while effectively recovering its sensible heat, realizing the dual functions of cooling and waste heat recovery, further improving the overall thermal efficiency of the system.

[0044] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0045] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0046] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0047] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0048] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A steel slag sensible heat recovery system, characterized in that, include: The first chain grate machine has a high-temperature liquid slag tank at its feed end and outputs medium-temperature steel slag at its discharge end. The second chain grate machine is located above the first chain grate machine. The feed end of the second chain grate machine is equipped with a scrap steel trough, and the discharge end of the second chain grate machine is equipped with a scrap steel receiving tank. The third chain grate machine has its inlet end connected to the outlet end of the first chain grate machine, and its outlet end is equipped with a cooling slag tank. A first air supply device, the first air supply device being used to deliver cold air; The second air supply device is used to deliver cold air. The first sealing cover is sequentially installed over the second chain grate machine and the first chain grate machine. The first sealing cover is provided with a first air outlet for communicating with the boiler and a first air inlet for communicating with the first air supply device. as well as, The second sealing cover is provided on the third chain grate machine. The second sealing cover is provided with a second air outlet for communicating with the boiler and a second air outlet for communicating with the second air supply device.

2. The steel slag sensible heat recovery system according to claim 1, characterized in that, The first chain grate machine, the second chain grate machine, and the third chain grate machine are all made of high-temperature resistant materials.

3. The steel slag sensible heat recovery system according to claim 2, characterized in that, The first chain grate machine has a high temperature resistance greater than 1300℃; The second chain grate machine has a high temperature resistance of 1200℃~1300℃; The third chain grate machine has a high temperature resistance of 1000℃~1200℃.

4. The steel slag sensible heat recovery system according to claim 1, characterized in that, The steel slag sensible heat recovery system also includes a first air outlet pipe and a second air outlet pipe. The first air outlet of the first sealing cover is connected to the boiler through the first air outlet pipe; The second air outlet of the second sealing cover is connected to the boiler through the second air outlet duct.

5. The steel slag sensible heat recovery system according to claim 4, characterized in that, The second air outlet duct is connected to the first air outlet duct, and the steel slag sensible heat recovery system further includes a first check valve provided in the first air outlet duct and a second check valve provided in the second air outlet duct. The first check valve is located upstream of the connection point between the first air outlet duct and the second air outlet duct; The second check valve is located upstream of the connection point between the first air outlet duct and the second air outlet duct.

6. The steel slag sensible heat recovery system according to any one of claims 1-5, characterized in that, The first chain grate machine is also provided with a bottom material trough at the feed end, which is used to hold the steel slag particles at the discharge end of the third chain grate machine.

7. The steel slag sensible heat recovery system according to any one of claims 1-5, characterized in that, The first air supply device includes a first blower, a first air duct, and a first air distributor; the inlet end of the first blower is connected to a cold air source, and the outlet end of the first blower is connected to the first air distributor through the first air duct. The first air distributor includes a first distributor body and a plurality of first nozzles disposed on the first distributor body. The inner diameter of the first nozzles gradually increases from the first blower end to the first chain grate end. The first nozzles are connected to and communicate with the first sealing cover.

8. The steel slag sensible heat recovery system according to any one of claims 1-5, characterized in that, The second air supply device includes a second blower, a second air duct, and a second air distributor; the inlet end of the second blower is connected to a cold air source, and the outlet end of the second blower is connected to the second air distributor through the second air duct. The second air distributor includes a second distributor body and a plurality of second nozzles disposed on the second distributor body. The inner diameter of the second nozzles gradually increases from the second blower end to the third chain grate end. The second nozzles are connected to and communicate with the second sealing cover.

9. The steel slag sensible heat recovery system according to any one of claims 1-5, characterized in that, A crusher is also provided between the discharge end of the first chain grate and the feed end of the third chain grate; The steel slag sensible heat recovery system also includes a third sealing cover, which is installed over the crusher.

10. A recovery method based on the steel slag sensible heat recovery system according to any one of claims 1-9, characterized in that, Includes the following steps: The system startup steps are as follows: the first air supply device forms a first heat exchange airflow sequentially through the first chain grate machine, the second chain grate machine, and the boiler; the second air supply device forms a second heat exchange airflow sequentially through the third chain grate machine and the boiler. Wherein, the first heat exchange airflow exchanges heat with the high-temperature liquid steel slag on the first chain grate machine to cool the high-temperature liquid steel slag to 850℃~900℃, and the temperature of the first heat exchange airflow after exchanging heat with the high-temperature liquid steel slag is 1000℃~1100℃. The first heat exchange airflow exchanges heat with the scrap steel on the second chain grate machine to preheat the scrap steel to 700℃~800℃, and the temperature of the first heat exchange airflow after exchanging heat with the scrap steel is 800℃~900℃; The second heat exchange airflow exchanges heat with the steel slag conveyed by the third chain grate machine to cool the steel slag to below 100°C. The temperature of the second heat exchange airflow after exchanging heat with the steel slag is 450°C to 500°C.

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