Steel slag waste heat recovery system

Abstract

The utility model discloses a steel slag waste heat recovery system which is characterized in that a rolling crushing device is arranged in a crushing area, a feeding hole and a discharging hole are formed in the rolling crushing device, a slag disc is arranged at the discharging hole, and the slag disc is detachably mounted on a movable carrier; the waste heat treatment area is provided with a material receiving port located at the upper part, and a screening device, a waste heat recovery device and a digestion device which are located at the lower part; a screening mechanism, a discharging chute and a lower chute are arranged in the screening device; a waste steel accumulation area is arranged at the other end of the side unloading chute; the waste heat recovery device is connected in parallel between the lower chute and the digestion device; and the slag tray is conveyed to the material receiving opening from the movable carrier by the hoisting device. The metal recovery rate is effectively improved; and large waste steel and large steel slag can be prevented from entering a subsequent waste heat recovery area and a digestion area, and the service life of equipment is prolonged. Waste heat recovery is carried out on the crushed steel slag, the contact area of the steel slag and a heat exchange medium is remarkably increased, and the heat exchange efficiency and the steam yield are improved.

Description

Technical Field

[0001] This utility model relates to the field of iron and steel metallurgy technology, specifically to a steel slag waste heat recovery system. Background Technology

[0002] In the converter steelmaking process, approximately 120 kg of slag is produced per ton of steel. The temperature of the steel slag typically reaches 1400℃~1600℃, and each ton of slag contains the equivalent heat of about 60 kg of standard coal, making it a rich source of waste heat. Currently, steel slag is mainly treated by roller crushing followed by pressurized hot quenching, or by pit-type hot quenching or air / water quenching. These methods not only waste a large amount of heat energy but also may cause environmental pollution and pose certain safety risks. Although steel slag heat recovery technologies exist, such as dry granulation, practical applications still suffer from poor adaptability to different slag forms, low efficiency, short equipment lifespan, high equipment investment, and high operating and maintenance costs.

[0003] In addition, steel slag contains a large amount of scrap steel, and the scrap steel in the slag is disposed of together with the slag, resulting in waste of scrap steel. Therefore, developing an efficient, economical, and environmentally friendly method for recovering waste heat from converter steel slag is of great significance. Utility Model Content

[0004] To address the aforementioned shortcomings of existing technologies, a steel slag waste heat recovery system is provided to improve heat recovery rate and metal recovery rate.

[0005] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows:

[0006] Firstly, the steel slag waste heat recovery system includes...

[0007] Several crushing zones are provided, and roller crushing devices are provided in the crushing zones. The roller crushing devices are provided with feed inlets and discharge outlets. A slag pan is provided at the discharge outlet. The slag pan is detachably installed on a mobile carrier.

[0008] Several waste heat treatment zones are provided, with a receiving port at the top and a screening device, a waste heat recovery device, and a digestion device at the bottom. The screening device is equipped with an inclined screening mechanism, a side discharge chute connected to the lower side of the upper part of the screening mechanism, and a lower chute connected to the lower part of the screening mechanism. At the other end of the side discharge chute, there is a scrap steel accumulation area. The waste heat recovery device is connected in parallel between the lower chute and the digestion device.

[0009] Several hoisting devices are used to transport the slag pan from a mobile carrier to the receiving port.

[0010] According to the above technical solution, the waste heat recovery device includes several hollow cylindrical structures driven by a power unit to rotate, a multi-layer water-cooled cavity disposed on the inner wall of the hollow cylindrical structure, a steam drum forming a water circulation loop with the multi-layer water-cooled cavity, and a heat accumulator connected to the steam drum; one end of the hollow cylindrical structure is rotatably connected to the lower chute, and the other end of the hollow cylindrical structure is connected to the digestion structure. Steel slag enters the digestion structure through the hollow cylindrical structure and the lower chute; the steam drum is connected to an external water supply pipeline. Low-temperature water enters the multi-layer water-cooled cavity through the downcomer between the steam drum and the water-cooled cavity, and after heat exchange, forms steam. High-temperature water enters the steam drum through the upcomer between the steam drum and the water-cooled cavity. After steam-water separation in the steam drum, the steam is transported to the heat accumulator for storage; the heat accumulator is connected to an external steam user.

[0011] According to the above technical solution, multiple rotating support seats are provided at intervals at the bottom of the hollow cylindrical structure, and several rollers parallel to the axis of the hollow cylindrical structure are provided on the rotating support seats.

[0012] According to the above technical solution, a rotary joint is provided at the end of the hollow cylindrical structure located at the discharge port. The rotary joint is provided with an inlet and an outlet, which are respectively connected to the downcomer pipe and the upcomer pipe.

[0013] According to the above technical solution, the roller crushing device includes a box structure, a tilting mechanism for supporting the slag pot, a spraying device for cooling, and a roller pressing mechanism for crushing steel slag; both the tilting mechanism and the roller pressing mechanism are fixed inside the box structure; a feed inlet is provided at the top of the box structure, the tilting mechanism is located below the feed inlet, the roller pressing mechanism is located on the side of the tilting mechanism, and a discharge outlet is provided on the box structure below the roller pressing mechanism; the slag pot is hoisted to the tilting mechanism by a hoisting device and tilted by the tilting mechanism, and the liquid steel slag is poured to the roller pressing mechanism; the spraying device is located at the top of the box structure; a track and a moving trolley are provided at the discharge outlet as a moving device, the track extends to the outside of the roller pressing mechanism, and the slag pan is placed on the moving trolley.

[0014] According to the above technical solution, it also includes a mobile dust removal hood, which is installed on top of the screening device or roller pressing mechanism in a sliding connection manner; the mobile dust removal hood is provided with a working position and a standby position, and when in the working position, the mobile dust removal hood is located directly above the screening device or roller pressing mechanism; the mobile dust removal hood is connected to the external dust removal facility through pipes and valves.

[0015] According to the above technical solution, a bottom-opening discharge port is provided at the bottom of the slag pan.

[0016] According to the above technical solution, the digestion device includes a closed box, a conveyor belt placed inside the closed box, a spray device located at the top of the conveyor belt, and a digestion chamber connected to the end of the conveyor belt; the beginning of the conveyor belt is connected to a waste heat recovery device, and the sealed box is covered on the outside of the conveyor belt; several spray devices are arranged at intervals along the length of the conveyor belt; the digestion chamber is connected to an external transfer facility.

[0017] According to the above technical solution, the screening particle size of the screening device is in the range of 20mm~40mm.

[0018] According to the above technical solution, the mobile carrier is a slag receiving car, and the slag pan is installed on the slag receiving car.

[0019] This utility model has the following beneficial effects:

[0020] 1. After the steel slag is crushed, a screening device is added to remove large pieces of scrap steel and slag. These large pieces are then centrally collected and transported to the converter for recycling. The remaining smaller pieces of steel slag are then transported to the waste heat recovery zone for waste heat recovery. This not only effectively improves the metal recovery rate (estimated to increase by 10%), but also prevents large pieces of scrap steel and slag from entering the subsequent waste heat recovery and digestion zones, thus avoiding impact on the equipment and reducing the pressure on subsequent processing steps, and extending the equipment's service life.

[0021] In addition, waste heat recovery from the crushed steel slag significantly increases the contact area between the steel slag and the heat exchange medium, thereby improving heat exchange efficiency and steam production compared to the uncrushed steel slag.

[0022] 2. Between the crushing zone and the waste heat treatment zone, the steel slag is temporarily placed in a slag pan, which is transported by a mobile carrier and hoisting device. Steel slag output from one crushing zone can be transported to any waste heat treatment zone via the mobile carrier and hoisting device, achieving a flexible connection between the crushing zone and the waste heat treatment zone. Compared to existing technologies where the roller crusher and waste heat recovery device are connected by a conveyor belt, this avoids the situation where damage to any of the roller crusher, waste heat recovery device, or conveyor belt would lead to a system shutdown for maintenance, significantly improving the efficiency of waste heat recovery.

[0023] 3. By setting a self-rotating hollow cylindrical structure as the main body of the waste heat recovery device, the steel slag particles after roller crushing and screening are small, and can fully contact the inner wall of the drum during rotation, so as to carry out full heat exchange, significantly improving heat exchange efficiency and increasing steam production by 15%. In addition, during the rotation of the hollow cylindrical structure, the steel slag is lifted and fallen with the rotation of the hollow cylindrical structure, and the steel slag comes into contact with each other, achieving the effect of steel slag crushing; it can also reduce the equipment wear rate by 40% and improve the equipment life.

[0024] 4. By setting up mobile dust removal vehicles, there is no steam or smoke overflow during the entire process. The exhaust gas is discharged after meeting the standards, which fundamentally solves the problem of fugitive emission of dust-containing flue gas in the steel slag treatment process and reduces environmental pollution.

[0025] The above description is merely an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it according to the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings. The specific implementation methods of this utility model are given in detail in the following embodiments and their accompanying drawings. Attached Figure Description

[0026] The accompanying drawings, which are included to provide a further understanding of the present invention and form part of this application, illustrate exemplary embodiments of the present invention and are used to explain the present invention, but do not constitute an undue limitation of the present invention.

[0027] Figure 1 This is a structural schematic diagram of an embodiment provided by this utility model;

[0028] Figure 2 yes Figure 1 Sectional view of AA;

[0029] Figure 3 yes Figure 1 Sectional view of BB;

[0030] Figure 4 yes Figure 1 Sectional view of CC;

[0031] In the diagram, 1. Crushing zone; 2. Roller crushing device; 2-1. Box structure; 2-2. Roller mechanism; 2-3. Feed inlet; 2-4. Discharge outlet; 3. Slag pan; 4. Mobile carrier; 5. Waste heat treatment zone; 6. Receiving port; 7. Screening device; 7-1. Screening mechanism; 7-2. Side discharge chute; 7-3. Lower chute; 8. Waste heat recovery device; 8-1. Hollow cylindrical structure; 8-2. Steam drum; 8-3. Heat accumulator; 8-4. Rotary support base; 8-5. Rotary joint; 8-6. Water inlet; 8-7. Water outlet; 9. Digestion device; 9-1. Enclosed box; 9-2. Conveyor belt; 9-3. Digestion bin; 10. Scrap steel accumulation area; 11. Lifting device; 12. Mobile dust collector; 13. Truck; 14. Slag hopper; 15. Slag hopper transport vehicle. Detailed Implementation

[0032] The following is in conjunction with the appendix Figures 1-4The principles and features of this utility model are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of this utility model. The utility model is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of this utility model will become clearer from the following description and claims. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this utility model.

[0033] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] Reference Figures 1-4 As shown, this utility model provides a steel slag waste heat recovery system.

[0036] Example 1

[0037] include

[0038] Several crushing zones 1 are provided, and a roller crushing device 2 is provided in each crushing zone. The roller crushing device is provided with a feed inlet and a discharge outlet. A slag pan 3 is provided at the discharge outlet. The slag pan is detachably installed on a mobile carrier 4. In this embodiment, preferably, the mobile carrier is a slag receiving car, and the slag pan is installed on the slag receiving car.

[0039] Several waste heat treatment zones 5 are provided, each with an upper receiving port 6 and a lower screening device 7, a waste heat recovery device 8, and a digestion device 9. The screening device includes an inclined screening mechanism 7-1, a side discharge chute 7-2 connected to the lower side of the upper part of the screening mechanism, and a lower chute 7-3 connected to the lower part of the screening mechanism. At the other end of the side discharge chute, there is a scrap steel accumulation area 10. The waste heat recovery device is connected in parallel between the lower chute and the digestion device. The steel slag is screened by the screening device to remove large pieces of scrap steel. The separated large pieces of scrap steel are stored in the large pieces of scrap steel accumulation area through the side discharge chute. The screened steel slag is then fed into the drum waste heat recovery device through the lower chute for waste heat recovery treatment.

[0040] Several hoisting devices 11 are used to transport the slag pan from a mobile carrier to the receiving port. In this embodiment, a casting crane is used as the hoisting device. The casting crane lifts the slag pan containing hot granulated steel slag to the receiving port above the screening device for screening. The steel slag in the slag pan is discharged from the bottom and enters the screening device through the receiving port for screening.

[0041] As shown in the embodiment, a crushing zone and a waste heat treatment zone are adopted. The process occupies a small area, and only one span of plant can meet the process requirements, resulting in low total investment.

[0042] In this application, a screening device is added to the system to remove large pieces of scrap steel and slag from the crushed steel slag. These large pieces are then centrally collected and transported to the converter for recycling. Additionally, the remaining smaller-sized steel slag is transported to a waste heat recovery device for waste heat recovery. This not only effectively improves the metal recovery rate, expected to increase it by 10%, but also prevents large pieces of scrap steel and slag from entering the subsequent waste heat recovery and digestion zones, thus avoiding impact and damage to the equipment and reducing the pressure on subsequent processing steps. Waste heat recovery from the crushed steel slag, compared to before crushing, increases the contact area between the steel slag and the slag, improving heat exchange efficiency and steam production.

[0043] Furthermore, between the crushing zone and the waste heat treatment zone, the steel slag is temporarily placed in a slag pan, which is transported by a mobile carrier and hoisting device. Steel slag output from one crushing zone can be transported to any waste heat treatment zone via the mobile carrier and hoisting device, achieving a flexible connection between the crushing zone and the waste heat treatment zone. Compared to existing technologies, the roller crushing device and the waste heat recovery device are connected by a conveyor belt; this avoids the situation where damage to any of the roller crushing device, waste heat recovery device, or conveyor belt would lead to a system shutdown for maintenance; and significantly improves the efficiency of waste heat recovery.

[0044] Example 2

[0045] Based on Example 1, a preferred waste heat recovery device is presented.

[0046] The waste heat recovery device includes several hollow cylindrical structures 8-1 driven by a power unit to rotate, a multi-layer water-cooled cavity (not shown in the figure) on the inner wall of the hollow cylindrical structure, a steam drum 8-2 forming a water circulation loop with the multi-layer water-cooled cavity, and a heat accumulator 8-3 connected to the steam drum. One end of each hollow cylindrical structure is rotatably connected to a lower chute, and the other end is connected to a digestion structure. Steel slag enters the digestion structure through the hollow cylindrical structure and the lower chute. The steam drum is connected to an external water supply pipeline. Low-temperature water enters the multi-layer water-cooled cavity through a downcomer between the steam drum and the water-cooled cavity. After heat exchange, it forms steam. High-temperature water enters the steam drum through a rising pipe between the steam drum and the water-cooled cavity. After steam-water separation in the steam drum, the steam is transported to the heat accumulator for storage. The heat accumulator is connected to an external steam user.

[0047] Specifically, in the above structure, the hollow cylindrical structure driven by the power unit, the steam drum, and the heat accumulator are common existing structures that can be selected according to requirements. The power unit driving the rotation of the hollow cylindrical structure is preferably an electric motor. For example, a driven gear is provided on the outer wall of the hollow cylindrical structure, and a driving gear meshing with the driven gear is provided on the external mounting surface. The motor and the driving gear are connected. Furthermore, to ensure smooth rotation of the hollow cylindrical structure, multiple rotating support seats 8-4 are spaced apart at the bottom of the hollow cylindrical structure, and several rollers parallel to the axis of the hollow cylindrical structure are provided on the rotating support seats.

[0048] The hollow cylindrical structure of the waste heat recovery device features multi-layered water-cooled cavities on its sidewalls. One end of the hollow cylindrical structure is rotatably connected to a lower chute, while the other end has a discharge port located above the digestion and cooling machine conveyor belt of the digestion structure. A rotary joint 8-5 is located at the discharge port end of the hollow cylindrical structure, with an inlet 8-6 and an outlet 8-7. The inlet and outlet are connected to a downcomer pipe and an upcomer pipe, respectively, thus forming a water-cooled circulation pipeline connecting the multi-layered water-cooled cavities and the steam drum. Using cooling water as the heat exchange medium enables multi-stage utilization of waste heat, reducing energy consumption.

[0049] During waste heat recovery, external feedwater facilities supply water to the steam drum. The low-temperature water in the steam drum enters the multi-layered water-cooled chamber with a hollow cylindrical structure through the downcomer and the inlet of the rotary joint. The heat from the steel slag is transferred to the low-temperature cooling water through contact with the inner wall of the hollow cylindrical structure. The cooling water absorbs the heat from the steel slag, causing some of the boiler water to vaporize. The steam-water mixture enters the steam drum through the riser pipe of the rotary joint, where steam and water are separated. The separated water re-enters the hollow cylindrical waste heat recovery device from the bottom of the steam drum through the downcomer, forming a closed water circulation loop between the multi-layered water-cooled chamber and the steam drum. The steam separated from the steam drum enters the accumulator for storage through pipelines, and after pressure adjustment, it is sent to external steam users.

[0050] In the above embodiment, by setting a self-rotating hollow cylindrical structure as the main body of the waste heat recovery device, the steel slag particles after roller crushing and screening are small, and can fully contact the inner wall of the drum during rotation, so as to carry out sufficient heat exchange, significantly improving the heat exchange efficiency and increasing steam production by 15%. In addition, during the rotation of the hollow cylindrical structure, the steel slag is lifted and falls with the rotation of the hollow cylindrical structure, and the steel slag comes into contact with each other, achieving the effect of steel slag crushing; it can also reduce the equipment wear rate by 40% and improve the equipment life.

[0051] In embodiments 1-2, a preferred roller crushing device is provided. The roller crushing device includes a box structure 2-1, a tilting mechanism for supporting the slag pot 14, a spraying device for cooling, and a roller crushing mechanism 2-2 for crushing steel slag. Both the tilting mechanism and the roller crushing mechanism are fixed inside the box structure. A feed inlet 2-3 is provided at the top of the box structure, with the tilting mechanism located below it and the roller crushing mechanism located to the side of the tilting mechanism. A discharge outlet 2-4 is provided on the box structure below the roller crushing mechanism. The slag pot is lifted to the tilting mechanism by a hoisting device and tilted, allowing the liquefied steel slag to be poured onto the roller crushing mechanism. The spraying device is located at the top of the box structure. A track and a moving trolley are provided at the discharge outlet as a moving device. The track extends to the outside of the roller crushing mechanism, and the slag pan is placed on the moving trolley. The moving trolley has a working position and a hoisting position on the track. The working position is located at the lower end of the box discharge outlet, and the hoisting position is located outside the box structure.

[0052] The electric actuator of the roller crusher is located outside the housing structure, away from high-temperature areas, resulting in a good operating environment, low failure rate, and convenient maintenance.

[0053] In Example 2, to reduce dust during the screening process, a movable dust collector hood 12 is also included. The movable dust collector hood is slidably mounted on top of the screening device or roller pressing mechanism. The movable dust collector hood has a working position and a standby position. In the working position, the movable dust collector hood is located directly above the screening device or roller pressing mechanism. The movable dust collector hood is connected to an external dust removal facility via pipes and valves. Due to the installation of the movable dust collector hood, there is no steam or dust overflow during the entire process, and the exhaust gas is discharged only after meeting standards, fundamentally solving the problem of unorganized emission of dust-laden flue gas in the steel slag treatment process and reducing environmental pollution.

[0054] A bottom-opening discharge port is provided at the bottom of the slag pan. The discharge opening is adjusted by hydraulic valves on both sides of the bottom of the slag pan, and the screening speed is adjusted in conjunction with the discharge chute, thereby improving the screening effect.

[0055] In this application, the mobile dust collector hood can be slidably connected to the top of the screening device via guide rails, or it can be integrated onto a mobile trolley and moved to the top of the screening device via the trolley. As shown in the embodiment depicted, a mobile dust collector hood trolley is used. During slag tray hoisting, the mobile dust collector hood trolley is in the standby position; during slag tray unloading, the mobile dust collector hood trolley moves to the working position. The mobile dust collector hood trolley is connected to external dust collection facilities via pipes and valves, enabling flue gas collection.

[0056] In Examples 1-2, a preferred digestion device is provided, which includes a closed box 9-1, a conveyor belt 9-2 placed inside the closed box, a spray device located at the top of the conveyor belt, and a digestion chamber 9-3 connected to the end of the conveyor belt; the beginning of the conveyor belt is connected to a waste heat recovery device, and the sealed box is covered on the outside of the conveyor belt; a number of spray devices are arranged at intervals along the length of the conveyor belt; the digestion chamber is connected to an external transfer facility.

[0057] In this application, the steel slag processed by the waste heat recovery device enters the first end of the conveyor belt. The conveyor belt is covered by a closed box. The closed box and the conveyor belt are made of high-temperature resistant and corrosion-resistant high-quality alloy materials, which can withstand temperatures of not less than 500°C and direct impacts from large slag blocks.

[0058] The conveyor belt operates continuously and its conveying capacity should be adjustable (frequency conversion speed regulation) to accommodate slag blocks of different sizes.

[0059] Inside the enclosed chamber, above the conveyor belt, multiple spray devices are arranged at intervals to rapidly cool the high-temperature hot material by spraying atomized water to achieve the purpose of slag-water mixing. The water-containing steel slag is transported to the digestion chamber for storage, where it stays for 2-3 hours to achieve the purpose of free calcium oxide digestion and slag-iron separation. The steam generated during the cooling process will be collected, treated by an external dust removal system, and then discharged.

[0060] The slag that has been digested is transported to other locations for secondary processing via external transfer facilities (belt conveyor / truck 13).

[0061] The working process of this utility model is as follows:

[0062] S1: Before crushing the steel slag, after the converter smelting is completed, the slag pot transport vehicle 15 carrying the slag pot is driven to the bottom of the converter furnace in advance. The high-temperature steel slag of the converter is discharged from the converter furnace mouth, collected through the slag pot, and transported from the steelmaking workshop to the slag treatment workshop for processing by the slag pot transport vehicle.

[0063] S2: Move the movable dust collector hood located at the top feed inlet of the roller crusher from the working position to the standby position; lift the slag pot containing liquid molten converter steel slag from the slag pot transport vehicle using a hoisting device (the embodiment in the figure uses a workshop casting crane), and then transport it through the discharge port at the top of the box structure to the tilting mechanism inside the roller crusher to support the slag pot; move the movable dust collector hood from the standby position to the working position.

[0064] Subsequently, the slag pot is tilted by a tipping mechanism, and the molten steel slag inside is poured onto the roller pressing mechanism. A spray system located at the top of the tank structure is activated, spraying cooling water to cool the molten steel slag, reducing its temperature from 1600℃ to ~900℃. Simultaneously, external dust removal facilities connected to a mobile dust collector remove fumes, completing the initial waste heat recovery. Afterward, the roller pressing mechanism crushes the initially cooled steel slag. Once crushed to the desired state, the discharge port at the bottom of the roller pressing mechanism is opened, and the fully crushed steel slag enters the slag pan at the bottom of the discharge port. After the steel slag in the slag pan accumulates to a set amount, a mobile carrier (here, a rail-mounted trolley) transports the slag pan from the bottom of the tank structure to an area accessible for lifting.

[0065] S3: Move the movable dust collector hood located at the top receiving port of the screening device from the working position to the standby position; use a hoisting device (in the embodiment shown, a workshop foundry crane is used) to lift the slag pan containing crushed steel slag from the mobile carrier and place the slag pan at the top receiving port of the screening device (a platform for placing the slag pan is provided at the top receiving port of the screening device). Then, move the movable dust collector hood from the standby position to the working position. The slag pan discharges material through the bottom; the discharge speed is controlled by controlling the opening at the bottom of the slag pan. Open the discharge port at the bottom of the slag pan to begin the discharge operation.

[0066] In step S3, the sieve particle size is one of 20mm to 40mm.

[0067] Preferably, steel slag and large scrap steel with a particle size greater than 30mm are screened out and piled up in the scrap steel accumulation area. After accumulating to a set amount, they are directly added to the converter for recycling as scrap steel. Steel slag with a particle size less than 30mm is transported to the waste heat recovery device for waste heat recovery, and the screening efficiency can reach more than 98%.

[0068] In addition, water spraying is carried out during the roller crushing process to reduce the temperature of the steel slag to a set value, and the flue gas generated during the roller crushing and spraying process is collected.

[0069] S4: Larger steel slag and scrap steel are transported to the scrap steel accumulation area for recycling in the converter, while smaller steel slag is transported to the waste heat recovery unit. Specifically, after being screened by the screening device, steel slag larger than the screening particle size slides off the screening device onto the side discharge chute and enters the scrap steel accumulation area. After a certain amount of larger steel slag accumulates in the scrap steel accumulation area, it is transported to the converter for recycling. Smaller steel slag passes through the screen holes of the screening mechanism and enters the lower chute at the bottom, flowing into the waste heat recovery unit from the lower channel.

[0070] Smaller steel slags enter the hollow cylindrical structure of the waste heat recovery device. As the hollow cylindrical device rotates, the steel slags are further broken down and come into full contact with the inner wall of the hollow cylindrical structure, thus achieving heat exchange.

[0071] S5: The steel slag processed by the waste heat recovery device enters the first end of the conveyor belt. The conveyor belt is covered by a closed box. The closed box and the conveyor belt are made of high-temperature resistant and corrosion-resistant high-quality alloy materials, which can withstand temperatures of not less than 500°C and direct impacts from large slag blocks.

[0072] The conveyor belt operates continuously and its conveying capacity should be adjustable (frequency conversion speed regulation) to accommodate slag blocks of different sizes.

[0073] Inside the enclosed chamber, above the conveyor belt, multiple spray devices are arranged at intervals to rapidly cool the high-temperature hot material by spraying atomized water to achieve the purpose of slag-water mixing. The water-containing steel slag is transported to the digestion chamber for storage, where it stays for 2-3 hours to achieve the purpose of free calcium oxide digestion and slag-iron separation. The steam generated during the cooling process will be collected, treated by an external dust removal system, and then discharged.

[0074] The slag that has been digested is transported to other locations for secondary processing via external transfer facilities (belt conveyor / truck 13).

[0075] In this application, a screening process is added after the steel slag is crushed to remove large pieces of scrap steel and slag. These large pieces are then centrally collected and transported to the converter for recycling. Secondly, the remaining smaller-sized steel slag is transported to the waste heat recovery zone for waste heat recovery. This not only effectively improves the metal recovery rate, expected to increase it by 10%, but also prevents large pieces of scrap steel and slag from entering the subsequent waste heat recovery and digestion zones, thus avoiding impact on the equipment and causing damage. This reduces the pressure on subsequent processing steps and extends the service life of the equipment.

[0076] In addition, waste heat recovery from the crushed steel slag can increase the contact area of ​​the steel slag compared to the uncrushed steel slag, thereby improving heat exchange efficiency and steam production.

[0077] The steel slag waste heat recovery system provided in this application is a mature, simple, and easy-to-operate device with a high safety factor, suitable for industrial production. It processes steel slag through roller crushing, screening, and waste heat recovery, and can handle different forms of hot steel slag. After crushing and dispersing, the contact area between the steel slag and the heat exchange medium is significantly increased, improving waste heat recovery efficiency. Using cooling water as the heat exchange medium enables multi-stage utilization of waste heat, reducing energy consumption. A complete dust removal system is installed throughout the process, preventing steam and dust overflow. Exhaust gas is discharged only after meeting standards, fundamentally solving the problem of fugitive emissions of dust-laden flue gas in steel slag treatment processes and reducing environmental pollution. The process requires a small footprint; only a single plant building is needed to meet the process requirements, resulting in low total investment.

[0078] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any way. Those skilled in the art can readily implement this utility model based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the utility model's technical solution, utilizing the disclosed technical content, are equivalent embodiments of this utility model. Furthermore, any equivalent changes, alterations, or variations made to the above embodiments based on the essential technology of this utility model are still within the protection scope of this utility model's technical solution.

Claims

1. A steel slag waste heat recovery system, characterized in that: include Several crushing zones are provided, and roller crushing devices are provided in the crushing zones. The roller crushing devices are provided with feed inlets and discharge outlets. A slag pan is provided at the discharge outlet. The slag pan is detachably installed on a mobile carrier. Several waste heat treatment zones are provided, with a receiving port at the top and a screening device, a waste heat recovery device, and a digestion device at the bottom. The screening device is equipped with an inclined screening mechanism, a side discharge chute connected to the lower side of the upper part of the screening mechanism, and a lower chute connected to the lower part of the screening mechanism. At the other end of the side discharge chute, there is a scrap steel accumulation area. The waste heat recovery device is connected in parallel between the lower chute and the digestion device. Several hoisting devices are used to transport the slag pan from a mobile carrier to the receiving port.

2. The steel slag waste heat recovery system according to claim 1, characterized in that: The waste heat recovery device includes several hollow cylindrical structures driven by a power unit, multi-layer water-cooled cavities on the inner wall of the hollow cylindrical structures, a steam drum forming a water circulation loop with the multi-layer water-cooled cavities, and a heat accumulator connected to the steam drum. One end of each hollow cylindrical structure is rotatably connected to a lower chute, and the other end is connected to a digestion structure. Steel slag enters the digestion structure through the hollow cylindrical structure and the lower chute. The steam drum is connected to an external water supply pipeline. Low-temperature water enters the multi-layer water-cooled cavities through a downcomer between the steam drum and the water-cooled cavities. After heat exchange, it forms steam. High-temperature water enters the steam drum through an upcomer between the steam drum and the water-cooled cavities. After steam-water separation in the steam drum, the steam is transported to the heat accumulator for storage. The heat accumulator is connected to an external steam user.

3. The steel slag waste heat recovery system according to claim 2, characterized in that: Multiple rotating support seats are spaced apart at the bottom of the hollow cylindrical structure, and several rollers parallel to the axis of the hollow cylindrical structure are provided on the rotating support seats.

4. The steel slag waste heat recovery system according to claim 2, characterized in that: A rotary joint is provided at the end of the hollow cylindrical structure located at the discharge port. The rotary joint is equipped with an inlet and an outlet, which are connected to the downcomer pipe and the upcomer pipe, respectively.

5. The steel slag waste heat recovery system according to claim 1, characterized in that: The roller crushing device includes a box structure, a tilting mechanism for supporting the slag pot, a spraying device for cooling, and a roller crushing mechanism for crushing steel slag. Both the tilting mechanism and the roller crushing mechanism are fixed inside the box structure. A feed inlet is located at the top of the box structure, with the tilting mechanism below it and the roller crushing mechanism located to the side of the tilting mechanism. A discharge outlet is located on the box structure below the roller crushing mechanism. The slag pot is hoisted to the tilting mechanism by a hoisting device and tilted, allowing the liquefied steel slag to be poured onto the roller crushing mechanism. The spraying device is located at the top of the box structure. A track and a moving trolley are provided at the discharge outlet as a moving device; the track extends to the outside of the roller crushing mechanism, and the slag pan is placed on the moving trolley.

6. The steel slag waste heat recovery system according to claim 1 or 5, characterized in that: It also includes a mobile dust collector, which is slidably mounted on top of the screening device or roller pressing mechanism. The mobile dust collector has a working position and a standby position. In the working position, the mobile dust collector is located directly above the screening device or roller pressing mechanism. The mobile dust collector is connected to the external dust removal facility through pipes and valves.

7. The steel slag waste heat recovery system according to claim 1, characterized in that: A bottom-opening discharge port is provided at the bottom of the slag pan.

8. The steel slag waste heat recovery system according to claim 1, characterized in that: The digestion device includes a closed box, a conveyor belt placed inside the closed box, a spray device located at the top of the conveyor belt, and a digestion chamber connected to the end of the conveyor belt; the beginning of the conveyor belt is connected to a waste heat recovery device, and the sealed box covers the outside of the conveyor belt; several spray devices are arranged at intervals along the length of the conveyor belt. The digestion chamber is connected to external transfer facilities.

9. The steel slag waste heat recovery system according to claim 1, characterized in that: The sieving particle size range of the sieving device is 20mm~40mm.

10. The steel slag waste heat recovery system according to claim 1, characterized in that: The mobile carrier is a slag receiving car, and the slag pan is installed on the slag receiving car.

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