High-temperature solid bulk waste heat direct recovery system applied to high-temperature blast furnace slag

Abstract

The invention discloses a high-temperature solid bulk waste heat direct recovery system applied to high-temperature blast furnace slag, which comprises a pouring tank for receiving and temporarily storing high-temperature molten blast furnace slag discharged from a metallurgical furnace; the crushing and screening device comprises a crusher and a conveying and screening mechanism, a feeding port of the crusher is connected with a discharging port of the material pouring tank, and a feeding port of the conveying and screening mechanism is connected with a discharging port of the crusher; the spraying type cooling device is used for cooling the high-temperature blast furnace slag entering the crusher; a feeding hole of the high-temperature solid bulk material waste heat direct recovery device is connected with a discharging hole of the conveying and screening device; and the tail end treatment device comprises a buffer tank, and a feed port of the buffer tank is connected with a discharge port of the high-temperature solid bulk waste heat direct recovery device. According to the invention, simultaneous heat exchange in the slag treatment process is realized, and high-temperature slag and high-value steam output is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-temperature blast furnace slag waste heat recovery, and particularly relates to a high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag. BACKGROUND

[0002] The steel industry is a major carbon emitter, accounting for 18% of the total carbon emissions in China, ranking second among all industrial categories. Therefore, achieving low carbonization has become an important measure to promote the high-quality development of the steel industry.

[0003] A large amount of blast furnace slag is generated during the blast furnace ironmaking process, and these blast furnace slags have a large amount of sensible heat during the smelting process. According to the data, the enthalpy heat of each ton of pig iron slag is about 683012 KJ, equivalent to 23.34 kg of standard coal, equivalent to 25 kg of coke.

[0004] In 2020, the national crude steel output reached 1053 million tons, and the slag output was 368 million tons. The slag heat was equivalent to 20077000 tons of standard coal heat, equivalent to 21970000 tons of coke heat, equivalent to 1000000 tons of coking plant 21.9.

[0005] At present, there are nearly 400 million tons of blast furnace slag, steel slag and phosphoric acid slag in China, which are basically treated by water quenching method, that is, a large amount of slag heat enters the water and cannot be recovered, resulting in great waste. At the same time, a large amount of water resources is also consumed. According to 1080m 3 The daily circulating water volume of the blast furnace is 10206m 3 , and the new water consumption is about 1000m 3 ; the circulating pump power is large, and the total power of the circulating pump system generally exceeds 1000kw. SUMMARY

[0006] The purpose of the present application is to provide a high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag to solve the problems mentioned in the background.

[0007] To solve the above technical problems, the present application provides a high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag, which comprises:

[0008] A pouring tank is used to receive and temporarily store high-temperature molten blast furnace slag discharged from a metallurgical furnace;

[0009] A crushing and screening device, which comprises a crusher and a conveying and screening mechanism, the feeding port of the crusher is connected with the discharging port of the pouring tank, and the feeding port of the conveying and screening mechanism is connected with the discharging port of the crusher;

[0010] A spraying type cooling device is used to cool the high-temperature blast furnace slag entering the crusher;

[0011] The high-temperature solid bulk material waste heat direct recovery device is connected with the discharge port of the conveying and screening device;

[0012] The tail end processing device comprises a buffer tank, and the feed inlet of the buffer tank is connected with the discharge port of the high-temperature solid bulk material waste heat direct recovery device.

[0013] Further, the crusher comprises a first crusher and a second crusher, the feed inlet of the first crusher is connected with the discharge port of the material reversing tank, the top of the first crusher is communicated with the spraying cooling device, the feed inlet of the second crusher is connected with the discharge port of the first crusher, and the discharge port of the second crusher is connected with the feed inlet of the conveying and screening mechanism.

[0014] Further, the feed inlet of the material reversing tank is connected with the discharge port of a slag tank, and the feed inlet of the slag tank is connected with a slag outlet of a blast furnace.

[0015] Further, the conveying and screening mechanism comprises an elevator conveyor and a screening machine, the feed inlet of the elevator conveyor is connected with the discharge port of the second crusher, the feed inlet of the screening machine is connected with the discharge port of the elevator conveyor, and the discharge port of the screening machine is connected with the feed inlet of the high-temperature solid bulk material waste heat direct recovery device.

[0016] Further, the elevator conveyor comprises an elevator bucket and an elevator, and the elevator is used for controlling the up-and-down movement of the elevator bucket.

[0017] Further, the elevator conveyor further comprises an upper hopper, the upper hopper is arranged above the elevator bucket, the feed inlet of the upper hopper is connected with the discharge port of the second crusher, and the discharge port of the upper hopper is connected with the feed inlet of the elevator bucket.

[0018] Further, the tail end processing device further comprises a rod mill and a magnetic separator, the feed inlet of the rod mill is connected with the discharge port of the buffer tank through a conveying device, the rod mill is used for crushing the blast furnace slag after heat exchange treatment, and the magnetic separator is used for magnetically separating and recovering metal iron from the crushed blast furnace slag.

[0019] The present application has the following beneficial effects: the present application realizes the simultaneous collection of slag heat through the spraying cooling device and the high-temperature solid bulk material waste heat direct recovery device, that is, the heat exchange and slag treatment are simultaneously performed, the high-temperature slag and high-temperature steam are output, on one hand, the controllable cooling ensures the glassification activity of the slag, that is, the cooling and crushing of the blast furnace slag do not change the properties of the blast furnace slag, and do not affect the subsequent utilization, and the subsequent resource utilization is completely met, on the other hand, the high-value steam can be produced, and the full resource utilization and high-value utilization of the blast furnace slag are realized. Meanwhile, the slag treatment and heat recovery are combined, and the land occupation is smaller. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention.

[0021] 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.

[0022] 21. First crusher; 22. Second crusher; 23. Conveying and screening mechanism; 51. Buffer tank.

[0023] 231. Elevating bucket; 232. Elevator; 233. Feeding bucket. Detailed Implementation

[0024] 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 merely one embodiment 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 protection scope of the present invention.

[0025] 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.

[0026] 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.

[0027] like Figure 1 As shown, this invention discloses a high-temperature solid bulk material waste heat direct recovery system applied to high-temperature blast furnace slag, which includes:

[0028] 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.

[0029] 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.

[0030] Spray cooling device 3 for cooling high-temperature blast furnace slag entering the crusher;

[0031] When the blast furnace slag enters the crusher, the spray cooling device 3 is started to accurately and controllably spray cool the high-temperature blast furnace slag. By controlling the cooling rate of the high-temperature blast furnace slag, the blast furnace slag forms a glassy structure with potential activity, laying a foundation for subsequent use as a building material raw material (such as a cement admixture), which solves the contradiction that the traditional water quenching method can form a glass body but wastes heat. At the same time, the blast furnace slag is rapidly solidified to form a solid brittle slag block, creating conditions for mechanical crushing. The cooled slag temperature drops to about 900°C, ensuring that it is in a completely solid state and will not stick again during subsequent conveying and processing.

[0032] The solidified slag block enters the crusher (such as a roller crusher) and is crushed into smaller particles. Then, the crushed slag particles are screened by the conveying and screening mechanism 23 to ensure that the slag particles entering the next link have uniform and appropriate particle sizes to optimize the heat exchange efficiency.

[0033] High-temperature solid bulk waste heat direct recovery device 4, the feed inlet of the high-temperature solid bulk waste heat direct recovery device 4 is connected with the discharge outlet of the conveying and screening mechanism 23; the device is directly coupled with high-temperature blast furnace slag cooling and waste heat recovery, that is, in the device, the high-temperature blast furnace slag directly contacts with the heat exchange pipe filled with water and steam as the medium. Heat is directly transferred from the high-temperature steel slag to the heat exchange medium in the heat exchange pipe through heat conduction and radiation between solids. It is heated into high-grade superheated steam for power generation or other industrial uses.

[0034] Since air is not introduced as a cooling medium, there is no secondary heat exchange, and the waste heat recovery efficiency is greatly improved. And since no intermediate medium is introduced, there is no new source of pollution, which has extremely high environmental protection characteristics. At the same time, there is no fan and other power equipment. If air cooling is used, the air slag ratio is large, and a large amount of air is needed for the fan, and the power consumption of the ton blast furnace slag air cooling system is about 40 kWh, which effectively reduces the construction cost and operating cost.

[0035] Tail end treatment device 5, the tail end treatment device 5 includes a buffer tank 51, the feed inlet of the buffer tank 51 is connected with the discharge outlet of the high-temperature solid bulk waste heat direct recovery device 4 through a conveying device. It ensures that the material continuously flows to the subsequent equipment, and cooperates with the reverse tank 1 at the front end of the system to solve the contradiction between the periodic and intermittent slagging of the blast furnace and the continuous and stable operation of the system.

[0036] The front and rear arrangement of the pouring tank 1 and the buffer tank 51 successfully converts the intermittent slag tapping of the blast furnace into continuous and stable operation of the system, ensures the continuous and stable output of waste heat recovery steam, and meets the requirements of power generation and industrial steam supply. Moreover, the system can realize the cooling, pulverization and heat utilization of the slag, that is, the heat utilization is realized while the slag is treated, so that the system has the advantages of water saving, energy saving, environmental protection and the like.

[0037] The present application realizes the heat recovery of the slag by the spraying cooling device 3 and the high-temperature solid bulk waste heat direct recovery device 4, that is, the heat exchange is realized during the slag treatment process, and the high-temperature slag and high-temperature steam are output. On the one hand, the controllable cooling ensures the glassification activity of the slag, that is, the cooling and crushing of the blast furnace slag do not change the properties of the blast furnace slag, and do not affect the subsequent utilization, completely meeting the subsequent resource utilization. On the other hand, high-value steam can be produced, realizing the full resource utilization and high-value utilization of the blast furnace slag. Moreover, the slag treatment and heat recovery are combined, and the land occupation is smaller.

[0038] In one embodiment, the crusher includes a first crusher 21 and a second crusher 22, the feeding port of the first crusher 21 is connected with the discharging port of the pouring tank 1, the top of the first crusher 21 is communicated with the spraying cooling device 3, the feeding port of the second crusher 22 is connected with the discharging port of the first crusher 21, and the discharging port of the second crusher 22 is connected with the feeding port of the conveying and screening mechanism 23.

[0039] Since the blast furnace slag has a high tapping temperature, and the temperature of the blast furnace slag in the crushing area still exceeds 1500 DEG C, the liquid-solid phase change and the glassification rate are considered, the spraying cooling device 3 is started when the blast furnace slag from the pouring tank 1 enters the first crusher 21, and the blast furnace slag in the first crusher 21 is precisely and controllably sprayed and cooled, so that the blast furnace slag is rapidly solidified to form solid brittle slag blocks, and meanwhile, the spraying cooling device 3 has a dust removal effect. By controlling the cooling rate, the blast furnace slag forms a glass body structure with potential activity, laying a foundation for 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 preliminarily crushed into large-sized blocks or particles. The temperature of the cooled slag is reduced to about 900 DEG C, so that the slag is in a completely solid state and will not be secondarily adhered during subsequent conveying and treatment.

[0040] The slag blocks (still large in size) after being coarsely crushed by the first crusher 21 immediately enter the second crusher 22 for fine crushing, so that the slag blocks are further crushed into smaller and more uniform particles. This two-stage series crushing mode ensures the crushing efficiency and the uniformity of the particle size of the blast furnace slag, creating optimal conditions for subsequent screening and efficient heat exchange.

[0041] After the second crusher 22 discharges material, it is screened by the conveying and screening mechanism 23 to control the particle size within the most suitable range for entering the solid-solid heat exchange device. Oversized particles can be returned to the crusher for further crushing.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] The above description of the disclosed embodiments enables those skilled in the art to make or use the 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, the 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 device; 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 1, 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. 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 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.

Images