A direct heat recovery system for high-temperature solid bulk materials applied to high-temperature blast furnace slag

Abstract

This utility model discloses a high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag. It includes a discharge tank for receiving and temporarily storing high-temperature molten blast furnace slag discharged from a metallurgical furnace; a crushing and screening device, comprising a crusher and a conveying and screening mechanism, with the inlet of the crusher connected to the outlet of the discharge tank and the inlet of the conveying and screening mechanism connected to the outlet of the crusher; a spray cooling device for cooling the high-temperature blast furnace slag entering the crusher; a high-temperature solid bulk material waste heat direct recovery device, with its inlet connected to the outlet of the conveying and screening device; and a tail-end treatment device, including a buffer tank, with its inlet connected to the outlet of the high-temperature solid bulk material waste heat direct recovery device. This utility model achieves simultaneous heat exchange during the slag treatment process, realizing the output of high-temperature slag and high-value steam.

Description

Technical Field

[0001] This utility model relates to the field of high-temperature blast furnace slag waste heat recovery technology, specifically to a high-temperature solid bulk waste heat direct recovery system applied to high-temperature blast furnace slag. Background Technology

[0002] As a major carbon emitter, the steel industry accounts for 18% of the country's total carbon emissions, ranking second among all industrial categories. Therefore, achieving low-carbonization has become an important measure to promote the leapfrog and high-quality development of the steel industry.

[0003] The blast furnace ironmaking process produces a large amount of blast furnace slag, which carries a significant amount of sensible heat during smelting. According to calculations, the enthalpy of 1 ton of pig iron slag produced is approximately 683012 KJ, equivalent to 23.34 kg of standard coal or 25 kg of coke.

[0004] In 2020, China's crude steel production reached 1.053 billion tons, while slag production was 368 million tons. The heat generated by the slag is equivalent to the heat of 20.077 million tons of standard coal, the heat of 21.97 million tons of coke, or the heat of 21.9 coking plants with a capacity of 1 million tons.

[0005] Currently, my country produces nearly 400 million tons of blast furnace slag, steel slag, and phosphoric acid slag, almost all of which are processed using water quenching. This means that a large amount of slag heat is released into the water and cannot be recovered, resulting in enormous waste. It also consumes a huge amount of water resources. (Based on 1080m...) 3 Blast furnace daily circulating water volume: 10206 m³ 3 It consumes approximately 1000m³ of fresh water. 3 The circulating pump has high power; the total power of the circulating pump system generally exceeds 1000kw. Summary of the Invention

[0006] The purpose of this invention is to provide a high-temperature solid bulk material waste heat direct recovery system for high-temperature blast furnace slag, in order to solve the problems mentioned in the background art.

[0007] To solve the above-mentioned technical problems, this utility model provides a high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag, which includes: A discharge hopper is used to receive and temporarily store high-temperature molten blast furnace slag discharged from a metallurgical furnace. A crushing and screening device, comprising a crusher and a conveying and screening mechanism, wherein the feed inlet of the crusher is connected to the discharge outlet of the discharge tank, and the feed inlet of the conveying and screening mechanism is connected to the discharge outlet of the crusher. A spray-type cooling device is used to cool the high-temperature blast furnace slag entering the crusher; A high-temperature solid bulk waste heat direct recovery device, wherein the inlet of the high-temperature solid bulk waste heat direct recovery device is connected to the outlet of the conveying and screening mechanism; The tail-end processing device includes a buffer tank, the inlet of which is connected to the outlet of the high-temperature solid bulk waste heat direct recovery device.

[0008] Furthermore, the crusher includes a first crusher and a second crusher. The feed inlet of the first crusher is connected to the discharge outlet of the discharge tank. The top of the first crusher is connected to the spray cooling device. The feed inlet of the second crusher is connected to the discharge outlet of the first crusher. The discharge outlet of the second crusher is connected to the feed inlet of the conveying and screening mechanism.

[0009] Furthermore, the feed inlet of the slag pot is connected to the discharge outlet of the slag pot, and the feed inlet of the slag pot is connected to the blast furnace slag outlet.

[0010] Furthermore, the conveying and screening mechanism includes a lifting conveyor and a screening machine. The feed inlet of the lifting conveyor is connected to the discharge outlet of the second crusher, the feed inlet of the screening machine is connected to the discharge outlet of the lifting conveyor, and the discharge outlet of the screening machine is connected to the feed inlet of the high-temperature solid bulk waste heat direct recovery device.

[0011] Furthermore, the lifting conveyor includes a lifting bucket and a lifting machine, wherein the lifting machine is used to control the lifting bucket to move up and down.

[0012] Furthermore, the lifting conveyor also includes a feeding hopper, which is disposed above the lifting bucket and has its inlet connected to the outlet of the second crusher, and its outlet connected to the inlet of the lifting bucket.

[0013] Furthermore, the tail-end processing device also includes a rod mill and a magnetic separator. The feed inlet of the rod mill is connected to the discharge outlet of the buffer tank through a conveying device for crushing the blast furnace slag after heat exchange treatment. The magnetic separator is used to magnetically separate and recover metallic iron from the crushed blast furnace slag.

[0014] The beneficial effects of this invention are as follows: This invention achieves simultaneous slag heat recovery through a spray-type cooling device and a high-temperature solid bulk material waste heat recovery device. That is, heat exchange occurs simultaneously during the slag treatment process, resulting in the output of high-temperature slag and high-value steam. On the one hand, controllable cooling ensures the vitrification activity of the slag, meaning that the cooling and crushing of blast furnace slag does not alter its properties and does not affect subsequent utilization, fully meeting its subsequent resource utilization needs. On the other hand, it can produce high-value steam, realizing the full resource utilization and high-value utilization of blast furnace slag. Simultaneously, by combining slag treatment and heat recovery into one, it requires less floor space. Attached Figure Description

[0015] Figure 1 This is a structural schematic diagram of an embodiment of the present utility model.

[0016] The components include: 1. Feeding hopper; 2. Crushing and screening device; 3. Spray cooling device; 4. High-temperature solid bulk material waste heat direct recovery device; 5. Tail-end treatment device; 6. Slag hopper.

[0017] 21. First crusher; 22. Second crusher; 23. Conveying and screening mechanism; 51. Buffer tank.

[0018] 231. Elevating bucket; 232. Elevator; 233. Feeding bucket. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only one embodiment of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] To make the objectives, technical solutions and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and specific embodiments.

[0021] In the following description, references to "an embodiment," "an embodiment," "an example," "example," etc., indicate that the described embodiment or example may include a particular feature, structure, characteristic, property, element, or limitation, but not every embodiment or example necessarily includes that particular feature, structure, characteristic, property, element, or limitation. Furthermore, the repeated use of the phrase "an embodiment according to this application," while possibly referring to the same embodiment, does not necessarily refer to the same embodiment.

[0022] like Figure 1 As shown, this utility model discloses a high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag, which includes: The charging tank 1 is used to receive and temporarily store the high-temperature molten blast furnace slag discharged from the metallurgical furnace; the molten blast furnace slag at approximately 1500°C discharged from the blast furnace first flows into the charging tank 1. This device plays a preliminary role in collection and buffering, ensuring stable feeding for subsequent processes.

[0023] The crushing and screening device 2 includes a crusher and a conveying and screening mechanism 23. The feed inlet of the crusher is connected to the discharge outlet of the discharge tank 1, and the feed inlet of the conveying and screening mechanism 23 is connected to the discharge outlet of the crusher. Spray-type cooling device 3 is used to cool the high-temperature blast furnace slag entering the crusher; As the blast furnace slag enters the crusher, the spray cooling device 3 is activated to precisely and controllably cool the high-temperature blast furnace slag. By controlling the cooling rate of the high-temperature blast furnace slag, it forms a potentially active glassy structure, laying the foundation for its subsequent use as a building material raw material (such as cement admixture). This solves the contradiction that traditional water quenching, while forming a glassy structure, wastes heat. Simultaneously, it rapidly solidifies the blast furnace slag, forming solid, brittle slag blocks, creating conditions for mechanical crushing. The cooled slag temperature drops to approximately 900℃, ensuring it remains completely solid and preventing secondary adhesion during subsequent transportation and processing.

[0024] The solidified slag blocks are fed into a crusher (such as a roller crusher) and broken into smaller particles. Subsequently, the crushed slag particles are screened by a conveying and screening mechanism 23 to ensure that the slag particles entering the next stage have a uniform and suitable particle size to optimize heat exchange efficiency.

[0025] The high-temperature solid bulk material waste heat direct recovery device 4 has its inlet connected to the outlet of the conveying and screening mechanism 23. This device directly couples high-temperature blast furnace slag cooling and waste heat recovery; that is, within this device, the high-temperature blast furnace slag is in direct contact with heat exchange tubes filled with water and steam as the medium. Heat is directly transferred from the high-temperature steel slag to the heat exchange medium inside the heat exchange tubes through heat conduction and radiation between the solids. This heat is then converted into high-grade superheated steam for power generation or other industrial applications.

[0026] Since no air is introduced as a cooling medium, there is no secondary heat exchange, and the efficiency of residual heat recovery is greatly improved. Furthermore, because no intermediate medium is introduced, no new pollution sources are generated, resulting in extremely high environmental protection characteristics. Simultaneously, there is no need for power equipment such as fans. If air cooling were used, the air-to-slag ratio would be large, requiring large-volume fans; the power consumption of an air-cooled system per ton of blast furnace slag is approximately 40 kWh. This solution effectively reduces construction and operating costs.

[0027] Tail-end processing device 5 includes a buffer tank 51. The feed inlet of the buffer tank 51 is connected to the discharge outlet of the high-temperature solid bulk material waste heat recovery device 4 via a conveying device. This ensures that the material flows continuously to the downstream equipment, echoing the unloading tank 1 at the front end of the system, and together they resolve the contradiction between the periodic and intermittent slag discharge of the blast furnace and the need for continuous and stable operation of the system.

[0028] By configuring the feed tank 1 and buffer tank 51 in front and behind, the intermittent slag discharge of the blast furnace was successfully converted into continuous and stable operation of the system, ensuring a continuous and stable output of waste heat recovery steam to meet the requirements of power generation grid connection or industrial steam supply. Furthermore, this system can achieve multiple process objectives such as slag cooling, pulverization, and heat utilization, that is, it realizes heat utilization while treating slag. This makes the system low in water consumption, low in electricity consumption, high in thermal efficiency, simple in process equipment, and low in investment, possessing advantages such as water saving, energy saving, and environmental protection.

[0029] This invention achieves simultaneous slag heat recovery through a spray-type cooling device 3 and a high-temperature solid bulk material waste heat recovery device 4. This means that heat exchange occurs simultaneously during the slag treatment process, resulting in the output of high-temperature slag and high-value steam. On one hand, controllable cooling ensures the vitrification activity of the slag, meaning that the cooling and crushing of the blast furnace slag does not alter its properties and does not affect subsequent utilization, fully meeting its subsequent resource utilization requirements. On the other hand, it can produce high-value steam, realizing the full resource utilization and high-value utilization of blast furnace slag. Furthermore, by combining slag treatment and heat recovery into one unit, it requires less floor space.

[0030] In one embodiment, the crusher includes a first crusher 21 and a second crusher 22. The feed inlet of the first crusher 21 is connected to the discharge outlet of the discharge tank 1, and the top of the first crusher 21 is connected to the spray cooling device 3. The feed inlet of the second crusher 22 is connected to the discharge outlet of the first crusher 21, and the discharge outlet of the second crusher 22 is connected to the feed inlet of the conveying and screening mechanism 23.

[0031] Because the blast furnace slag has a high discharge temperature, exceeding 1500℃ even in the crushing zone, considering the liquid-solid phase transition and glass transition rate, a spray cooling device 3 is activated when the blast furnace slag enters the first crusher 21 from the charging hopper 1. This provides precise and controllable spray cooling to the blast furnace slag in the first crusher 21, causing it to rapidly solidify into solid, brittle slag blocks. Simultaneously, this process also serves a dust removal function. By controlling the cooling rate, the blast furnace slag forms a potentially active glassy structure, laying the foundation for its subsequent use as a building material raw material. Under the mechanical action of the first crusher 21 (such as a roller crusher), the solidified slag blocks are initially crushed into larger blocks or particles. The cooled slag temperature drops to approximately 900℃, ensuring it remains completely solid and prevents secondary adhesion during subsequent transportation and processing.

[0032] The slag lumps (still relatively large in size) after coarse crushing by the first crusher 21 then enter the second crusher 22 for fine crushing, further breaking the slag lumps into smaller, more uniform particles. This two-stage series crushing mode ensures crushing efficiency and particle size uniformity of blast furnace slag, creating optimal conditions for subsequent screening and efficient heat exchange.

[0033] After the second crusher 22 discharges material, it is screened by the conveying and screening mechanism 23 to control the particles within the most suitable particle size range for entering the solid-solid heat exchange device. Oversized particles can be returned to the crusher for further crushing.

[0034] In one embodiment, the inlet of the charging hopper 1 is connected to the outlet of the slag pot 6, and the inlet of the slag pot 6 is connected to the blast furnace slag outlet. High-temperature molten blast furnace slag is first loaded into the slag pot 6. The slag pot 6, acting as a transport container for high-temperature molten slag, is transported to the charging hopper 1 via a trolley or crane. Transporting the slag through the slag pot 6 eliminates the need for a rigid connection between the waste heat recovery system and the blast furnace slag outlet. This allows the system to be located at a more suitable site further from the blast furnace, significantly alleviating the problem of limited space in the main process area of ​​a steel plant.

[0035] The slag pot 6 and the charging pot 1 together form a two-stage buffer system. The slag pot 6 solves the intermittent problem of slag discharge from the blast furnace body; the charging pot 1 solves the intermittent problem of feeding material from the slag pot 6 to the processing system. The combination of these two ensures that subsequent core processes such as crushing and heat exchange can obtain a highly continuous and stable material supply, which is a prerequisite for achieving efficient and stable heat recovery.

[0036] In one embodiment, the conveying and screening mechanism 23 includes a lifting conveyor and a screening machine. The feed inlet of the lifting conveyor is connected to the discharge outlet of the second crusher 22, the feed inlet of the screening machine is connected to the discharge outlet of the lifting conveyor, and the discharge outlet of the screening machine is connected to the feed inlet of the high-temperature solid bulk waste heat direct recovery device 4.

[0037] After two stages of crushing, the blast furnace slag enters the hoisting conveyor from the discharge port of the second crusher 22. The hoisting conveyor lifts the blast furnace slag from a lower position to a certain height, providing suitable height conditions for subsequent screening operations. This mechanical lifting method is more reliable and consumes less energy than relying on slope sliding or pneumatic conveying, and there is no dust escape, making it very suitable for conveying high-temperature materials. The blast furnace slag enters the screening machine from the discharge port of the hoisting conveyor. The screening machine screens the blast furnace slag, separating blast furnace slag particles that meet the preset particle size requirements from those that do not, ensuring that only qualified blast furnace slag particles that meet the preset particle size requirements can be discharged from its discharge port and enter the subsequent high-temperature solid bulk material waste heat direct recovery device 43. This ensures the uniformity and stability of the material entering the core heat exchange device. The material with uniform particle size can form a material layer with stable porosity and consistent flow within the heat exchange device, thereby ensuring that the contact thermal resistance between the heat exchange tube and the blast furnace slag is minimized and stable, which is an important prerequisite for achieving efficient and uniform heat exchange.

[0038] In one embodiment, the lifting conveyor includes a lifting bucket 231 and a hoist 232, the hoist 232 being used to control the vertical movement of the lifting bucket 231. By adjusting the operating speed of the hoist 232 and the loading capacity of the lifting bucket 231, the conveying volume of blast furnace slag can be flexibly adjusted. When the production scale expands or shrinks, the conveying volume can be adjusted in a timely manner to meet the needs of different production stages, avoiding system inefficiency or resource waste caused by mismatched conveying volumes.

[0039] In one embodiment, the lifting conveyor further includes a feeding hopper 233, which is positioned above the lifting bucket 231 and has its inlet connected to the outlet of the second crusher 22. The outlet of the feeding hopper 233 is connected to the inlet of the lifting bucket 231. The feeding hopper 233 serves to buffer and guide the material, and its volume design can accommodate the discharge volume of the second crusher 22 within a certain period of time, preventing the material from directly impacting the lifting bucket 231 and ensuring the stability of the material conveying.

[0040] In one embodiment, the tail-end processing device 5 further includes a rod mill and a magnetic separator. The feed inlet of the rod mill is connected to the discharge outlet of the buffer tank 51 via a conveying device for crushing the blast furnace slag after heat exchange treatment. The magnetic separator is used to magnetically separate and recover metallic iron from the crushed blast furnace slag.

[0041] Rod mills use internal steel rods as grinding media to grind and crush blast furnace slag. During the rotation of the rod mill, the steel rods collide and rub against each other, breaking the blast furnace slag into finer particles. This allows for better separation of metallic iron from other impurities in the blast furnace slag, improving the efficiency of subsequent magnetic separation for recovering metallic iron.

[0042] Magnetic separators use magnetic force to adsorb metallic iron from blast furnace slag, separating it from other non-magnetic impurities. The recovered metallic iron can be reused as a high-quality steelmaking raw material, while the remaining tailings can be used in the production of other building materials, transforming blast furnace slag from hazardous solid waste into a high-value resource.

[0043] The above description of the disclosed embodiments enables those skilled in the art to implement or use this invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, this invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag, characterized in that: include: A discharge hopper is used to receive and temporarily store high-temperature molten blast furnace slag discharged from a metallurgical furnace. A crushing and screening device, comprising a crusher and a conveying and screening mechanism, wherein the feed inlet of the crusher is connected to the discharge outlet of the discharge tank, and the feed inlet of the conveying and screening mechanism is connected to the discharge outlet of the crusher. A spray-type cooling device is used to cool the high-temperature blast furnace slag entering the crusher; A high-temperature solid bulk waste heat direct recovery device, wherein the inlet of the high-temperature solid bulk waste heat direct recovery device is connected to the outlet of the conveying and screening mechanism; The tail-end processing device includes a buffer tank, the inlet of which is connected to the outlet of the high-temperature solid bulk waste heat direct recovery device.

2. The high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag according to claim 1, characterized in that: The crusher includes a first crusher and a second crusher. The feed inlet of the first crusher is connected to the discharge outlet of the discharge tank. The top of the first crusher is connected to the spray cooling device. The feed inlet of the second crusher is connected to the discharge outlet of the first crusher. The discharge outlet of the second crusher is connected to the feed inlet of the conveying and screening mechanism.

3. The high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag according to claim 2, characterized in that: The feed inlet of the slag pot is connected to the discharge outlet of the slag pot, and the feed inlet of the slag pot is connected to the blast furnace slag outlet.

4. The high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag according to claim 2, characterized in that: The conveying and screening mechanism includes a lifting conveyor and a screening machine. The feed inlet of the lifting conveyor is connected to the discharge outlet of the second crusher, the feed inlet of the screening machine is connected to the discharge outlet of the lifting conveyor, and the discharge outlet of the screening machine is connected to the feed inlet of the high-temperature solid bulk waste heat direct recovery device.

5. A high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag according to claim 4, characterized in that: The lifting conveyor includes lifting buckets and a lifting machine, the lifting machine being used to control the vertical movement of the lifting buckets.

6. A high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag according to claim 5, characterized in that: The lifting conveyor also includes a feeding hopper, which is located above the lifting bucket and has its inlet connected to the outlet of the second crusher, and its outlet connected to the inlet of the lifting bucket.

7. A high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag according to claim 1, characterized in that: The tail-end processing device also includes a rod mill and a magnetic separator. The feed inlet of the rod mill is connected to the discharge outlet of the buffer tank through a conveying device and is used to crush the blast furnace slag after heat exchange treatment. The magnetic separator is used to magnetically separate and recover metallic iron from the crushed blast furnace slag.

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