Steel slag granulation waste heat recovery system

Abstract

A steel slag granulation waste heat recovery system belongs to the technical field of steel smelting equipment. Existing steel slag waste heat recovery wastes a large amount of fresh water resources, generates toxic gas, pollutes the environment and cannot efficiently recover waste heat. The steel slag granulation waste heat recovery system comprises a slag pool, a slag throwing mechanism and a waste heat recovery mechanism. Slag is stored in the slag pool; the slag throwing mechanism is communicated with the slag pool and can throw slag discharged from the slag pool to the periphery, so that the thrown slag exchanges heat with the introduced first heat exchange gas, and high-temperature waste gas and solid steel slag are obtained; the waste heat recovery mechanism communicates with the slag throwing mechanism and is used for exchanging heat with the high-temperature waste gas and the solid steel slag so as to recover waste heat of the high-temperature waste gas and the solid steel slag. The method is used for steel slag waste heat recovery.

Description

Technical Field

[0001] The invention belongs to the technical field of steel smelting equipment, and in particular relates to a steel slag granulation waste heat recovery system. Background Art

[0002] During the blast furnace steelmaking process, slag (primarily composed of CaO and SiO₂) must be removed from the furnace hearth to prevent accumulation and impact on smelting efficiency. Traditional slag treatment methods typically involve water quenching or dry slag pit cooling. While the water quenching method is widely used in industrial production due to its high efficiency, it also has numerous drawbacks. First, it wastes a significant amount of high-quality waste heat, as much of the water evaporates directly into the atmosphere at high temperatures, rendering this heat unrecoverable. Second, it wastes significant amounts of fresh water resources, with the slag-to-water ratio being approximately 1:1. This translates to a significant amount of fresh water consumed per ton of high-temperature slag treated. Third, it causes significant environmental pollution, as direct contact between water and slag produces large amounts of toxic gases such as H₂S and SO₂. The dry slag pit cooling method, which involves pouring molten blast furnace slag into a dry slag pit for air cooling, pollutes groundwater sources and releases large amounts of water vapor during cooling, along with H₂S and SO₂ gases, which corrode buildings, damage equipment, and degrade the working environment. Summary of the Invention

[0003] In view of this, the present invention provides a steel slag granulation waste heat recovery system, which can recover the waste heat of steel slag in multiple stages to avoid energy waste.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] The steel slag granulation waste heat recovery system includes:

[0006] a slag pool storing molten slag;

[0007] The slag throwing mechanism is connected to the slag pool and can throw the slag discharged from the slag pool to the surrounding area, so that the thrown slag exchanges heat with the first heat exchange gas introduced to obtain high-temperature waste gas and solid steel slag;

[0008] The waste heat recovery mechanism is connected to the slag rejection mechanism and is used for exchanging heat with the high-temperature exhaust gas and solid steel slag to recover the waste heat of the high-temperature exhaust gas and solid steel slag.

[0009] Furthermore, the slag removal mechanism includes at least one slag removal plate that can remove the slag; the slag removal plate is provided with a plurality of circumferentially arranged slag removal grooves, and the slag removal grooves are configured to apply force to the slag when the slag moves along the length direction of the slag removal groove under centrifugal force, so that the slag is cut into particles.

[0010] Furthermore, a high-speed airflow ring is provided outside each layer of the slag-sweeping plate. The high-speed airflow ring is provided with an annular air outlet along the circumferential direction. The high-speed airflow ring discharges air to perform circular cutting on the slag being swiped out.

[0011] Furthermore, the waste heat recovery mechanism includes a pulsating fluidized bed, a low-temperature economizer, a dust removal heat exchanger, a superheater and an evaporator. The pulsating fluidized bed is connected to the slag rejection mechanism. A second heat exchange gas is introduced into the pulsating fluidized bed to exchange heat with the solid steel slag flowing into the pulsating fluidized bed to obtain high-temperature gas; the high-temperature gas is introduced into the low-temperature economizer to exchange heat with the softened water introduced into the low-temperature economizer; the high-temperature exhaust gas flowing out of the slag rejection mechanism flows through the dust removal heat exchanger, the superheater and the evaporator in sequence, and the softened water flowing out of the low-temperature economizer flows through the dust removal heat exchanger, the evaporator and the superheater in sequence to exchange heat with the high-temperature exhaust gas step by step to obtain superheated steam.

[0012] Furthermore, it also includes a power generation mechanism connected to the superheater, and the superheated steam is passed into the power generation mechanism to generate power.

[0013] Furthermore, the power generation mechanism is connected to the low-temperature economizer so that the softened water after work is passed into the low-temperature economizer.

[0014] Furthermore, the dust removal heat exchanger includes a dust removal shell, a separation cone, a guide pipe, a dust collecting box and a high-temperature economizer. The separation cone and the guide pipe are arranged in the dust removal shell from top to bottom, the dust collecting box is arranged at the bottom of the dust removal shell, and the high-temperature economizer is mounted outside the dust collecting box; the high-temperature exhaust gas flows tangentially into the dust removal shell to separate the high-temperature gas and steel slag particles, and the separation cone isolates the high-temperature gas and steel slag particles so that the steel slag particles fall into the dust collecting box; an annular air duct is formed between the guide pipe and the inner wall of the dust removal shell, which is connected to the inside of the guide pipe, and the separated high-temperature gas flows to the superheater in turn from the guide pipe and the annular air duct; the softened water discharged from the low-temperature economizer is passed into the high-temperature economizer to exchange heat with the steel slag particles.

[0015] Furthermore, at least two levels of anti-condensation baffles are provided in the slag pool along the feeding direction and are staggered up and down.

[0016] Furthermore, the discharge port of the slag pool is provided with a flow control valve for controlling the amount of slag discharged from the slag pool.

[0017] Furthermore, the flow control valve includes a linear drive part, a connecting rod and a valve core. The cross-section of the valve core is trapezoidal. The valve core is inserted into the discharge port of the slag pool. One end of the connecting rod is connected to the valve core, and the other end is driven and connected to the linear drive part.

[0018] The beneficial effects of the present invention compared with the prior art are:

[0019] 1. This invention first uses cooling air as a heat exchange medium to exchange heat with the slag. The air then exchanges heat with softened water, avoiding the generation of toxic gases caused by direct heat exchange between the cooling water and the slag. Furthermore, the softened water is used in a closed loop, which not only avoids the waste of fresh water resources, but also increases the inlet water temperature of the waste heat recovery mechanism, further avoiding energy waste.

[0020] 2. The present invention designs two-stage anti-condensation baffles in the slag pool, which can disturb the feed in turn, prevent the slag from solidifying or splashing prematurely during the pouring process, and ensure the effective separation of molten steel and slag.

[0021] 3. The present invention achieves three-stage slag cutting. The first stage, an overflow pipe and slag outlet at the outlet of the first discharge pipe, separates large slag into small pieces. The second stage, a slag trough in the slag tray, separates small slag into granular slag. The third stage, circular airflow, separates the granular slag into smaller, more uniform slag. This allows for efficient heat exchange between the slag and the cooling air, improving heat exchange efficiency. Furthermore, the design of the slag-sweeping mechanism of the present invention eliminates the slag crushing and drying steps in conventional processes, directly producing fine slag (with a diameter of 0.1 to 5 mm). This eliminates intermediate steps, reduces power consumption and equipment maintenance costs. The slag granules produced by the present invention are highly active and can be directly used as cement admixture or roadbed material, reducing downstream grinding energy consumption (conventional processes require additional grinding to a specific surface area of ≥400 m² / kg). Dry processes such as centrifugal granulation do not require large amounts of cooling water, reducing pump energy consumption and water treatment costs.

[0022] 4. The waste heat recovery mechanism of the present invention is provided with a multi-stage heat exchange structure. The high-temperature exhaust gas discharged by the slag removal mechanism is subjected to multi-stage heat exchange with the cooling water to achieve sufficient heat exchange and improve energy utilization.

[0023] 5. The superheated steam discharged from the waste heat recovery mechanism of the present invention is passed into the power generation mechanism to generate electricity. The steam after power generation is condensed into condensed water and passed into the waste heat recovery mechanism to achieve a closed loop and avoid waste of water resources and energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are incorporated in and constitute a part of this application and are used to provide a further understanding of the present invention.

[0025] Figure 1 It is a structural schematic diagram of the steel slag granulation waste heat recovery system of the present invention.

[0026] Figure 2 It is a structural diagram of the coordination between the slag pool and the slag disposal mechanism.

[0027] Figure 3 Schematic diagram of the slag pool structure.

[0028] Figure 4 This is a structural diagram of the slag pool and flow control valve.

[0029] Figure 5 It is a structural diagram of the slag throwing mechanism.

[0030] Figure 6 It is a cross-sectional diagram of the slag removal mechanism.

[0031] Figure 7 This is an exploded diagram of the slag removal mechanism.

[0032] Figure 8 Schematic diagram of the structure of a pulsating fluidized bed.

[0033] Figure 9 Schematic diagram of the structure of the dust removal heat exchanger Figure 1 .

[0034] Figure 10 Schematic diagram of the structure of the dust removal heat exchanger Figure 2 .

[0035] Figure 11 This is a cross-sectional diagram of the dust removal heat exchanger.

[0036] Description of reference numerals:

[0037] 1-slag pool; 11-first discharge pipe; 111-overflow pipe; 112-discharge notch; 12-anti-condensation baffle; 13-flow control valve; 131-connecting rod; 132-valve core; 2-slag removal mechanism; 21-slag removal shell; 212-second discharge pipe; 22-casing; 23-slag removal motor; 231-motor shaft; 24-support chassis; 25-slag removal tray; 251-slag removal trough; 26-high-speed airflow ring; 27-long screw; 3-residue Heat recovery mechanism; 31-pulsating fluidized bed; 311-air inlet pipe; 32-low-temperature economizer; 33-dust removal heat exchanger; 331-dust removal housing; 3311-air inlet pipe; 3312-exhaust pipe; 332-separation cone; 333-guide pipe; 3331-exhaust hole; 334-dust collection box; 335-high-temperature economizer; 336-planetary feeder; 337-annular air duct; 34-superheater; 35-evaporator; 4-power generation mechanism. DETAILED DESCRIPTION

[0038] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Figure 1 FIG. 1 shows a structural diagram of a steel slag granulation waste heat recovery system according to this embodiment. Figure 1As shown, the steel slag granulation waste heat recovery system includes a slag pool 1, a slag disposal mechanism 2, a waste heat recovery mechanism 3 and a power generation mechanism 4. The slag pool 1 is used to store the steel slag discharged from the blast furnace. At this time, the temperature of the steel slag is about 1400 degrees, so it is in a liquid state and has a certain viscosity. The slag pool 1 is above the slag disposal mechanism 2 and is connected to the slag disposal mechanism 2. The slag is discharged to the slag disposal mechanism 2 by gravity. The slag disposal mechanism 2 can throw the slag to the surroundings to disperse the large pieces of slag. At the same time, cooling air is introduced into the slag disposal mechanism 2 as the first heat exchange gas to exchange heat with the slag. The first heat exchange gas after heat exchange forms high-temperature exhaust gas. The slag after heat exchange forms granular solid steel slag due to the lower temperature. At this time, the temperature of the solid steel slag is about 850°. The slag removal mechanism 2 is connected to the waste heat recovery mechanism 3 and passes high-temperature exhaust gas and solid slag into the waste heat recovery mechanism 3. The high-temperature exhaust gas and solid slag exchange heat with the softened water in the waste heat recovery mechanism 3, and the softened water is used to recover the waste heat of the high-temperature exhaust gas and solid slag. The waste heat recovery mechanism 3 converts the softened water after heat exchange into superheated steam and passes it into the power generation mechanism 4 to generate power. The softened water formed after the superheated steam is further passed into the waste heat recovery mechanism 3 to exchange heat with the high-temperature exhaust gas and solid slag, thus completing a closed-loop system. This achieves waste heat recovery from the slag and avoids energy waste. Furthermore, this embodiment first uses cooling air as the heat exchange medium to exchange heat with the slag, and then the heat exchanged air is exchanged with softened water, avoiding the generation of toxic gases that would result from direct heat exchange between cooling water and slag. The closed-loop use of softened water not only avoids the waste of fresh water resources, but also increases the inlet temperature of the waste heat recovery mechanism 3, further avoiding energy waste.

[0040] Figure 3 and Figure 4 The schematic diagram of the structure of the slag pool 1 of this embodiment is shown. Figure 2 、 Figure 3 and Figure 4The slag pool 1 of this embodiment is an inverted trapezoid. A discharge port is provided at the bottom of the slag pool 1. A first discharge pipe 11 is provided at the bottom of the slag pool 1. The upper end of the first discharge pipe 11 is connected to the discharge port at the bottom of the slag pool 1, and the lower end is connected to the slag-sweeping mechanism 2. Two-stage anti-condensation baffles 12 are arranged in an upper and lower staggered manner between the feed port and the discharge port in the slag pool 1. The anti-condensation baffle 12 near the feed port is higher than the anti-condensation baffle 12 near the discharge port. In this way, the two-stage anti-condensation baffles 12 can sequentially disturb the feed, prevent the slag from prematurely solidifying or splashing during the pouring process, and ensure the effective separation of molten steel and slag. The anti-condensation baffles 12 can also be designed with specific angles or openings to encourage the slag to form directional vortices and prevent local static areas from solidifying due to excessive heat dissipation (such as inclined baffles inducing natural convection). That is, the anti-condensation baffles 12 of this embodiment are based on optimizing the thermodynamic and fluid dynamic environment inside the slag pool 1 to delay or prevent the solidification of the slag. The anti-condensation baffle 12 can also be designed to be inclined or curved, using gravity to allow the slag to naturally flow back to the bottom of the slag ladle, while the molten steel flows smoothly out the other side, thus achieving separation of the slag and molten steel. In addition, the anti-condensation baffle 12 is usually made of refractory materials, such as high-aluminum and magnesium-carbon materials, which can withstand high temperatures and reduce direct contact between the slag and the cold air or the inner wall of the slag pool 1, thereby reducing the cooling rate of the slag and preventing premature solidification.

[0041] like Figure 4 As shown, the discharge port of the slag pool 1 of this embodiment is also provided with a flow control valve 13 for controlling the amount of slag discharged from the slag pool 1. The flow control valve 13 comprises a linear drive unit (not shown in the figure), a connecting rod 131 and a valve core 132. The cross section of the valve core 132 is an inverted trapezoid. The valve core 132 is inserted into the discharge port of the slag pool 1 and the upper pipe opening of the first discharge pipe 11. Figure 4 , the upper pipe opening of the first discharge pipe 11 is an inverted cone, so that an annular discharge channel is formed between the valve core 132 and the upper pipe opening of the first discharge pipe 11. One end of the connecting rod 131 is connected to the valve core 132, and the other end is connected to the linear drive unit. When the linear drive unit drives the valve core 132 to move upward through the connecting rod 131, the inner diameter of the annular discharge channel becomes larger, and the amount of slag discharged from the slag pool 1 increases; when the linear drive unit drives the valve core 132 to move downward through the connecting rod 131, the inner diameter of the annular discharge channel becomes smaller, and the amount of slag discharged from the slag pool 1 decreases, thereby achieving the adjustment of the slag discharge amount. Among them, a dial can also be set on the side of the connecting rod 131, and the connecting rod 131 is connected to the scale pointer. When the connecting rod 131 moves up and down, it drives the scale pointer to move synchronously, and the slag discharge amount is determined by the scale line indicated by the scale pointer.

[0042] Figure 5 、 Figure 6 and Figure 7 Shows the structural diagram of the slag removal mechanism 2, combined with Figure 5 、 Figure 6 and Figure 7The slag removal mechanism 2 of this embodiment includes a slag removal housing 21, a sleeve 22, a slag removal motor 23, a support chassis 24, and a slag removal pan 25. An air inlet is provided at the bottom of the slag removal housing 21, through which cooling air enters the slag removal housing 21 to exchange heat with the molten slag. The sleeve 22 extends through the bottom of the slag removal housing 21 and is inserted into the slag removal housing 21. The support chassis 24 is mounted at the upper end of the sleeve 22. The slag removal pan 25 has three upper and lower layers and is located above the support chassis 24. The slag removal motor 23 is arranged outside the slag removal shell 21, and the motor shaft 231 of the slag removal motor 23 is inserted into the sleeve 22 and extends upward. The axial end of the motor shaft 231 passes through the supporting chassis 24 and is fixedly connected to the slag removal pan 25 of the third layer through a coupling. The upper and lower slag removal pans 25 are connected to the slag removal pan 25 of the third layer through a long screw 27, thereby achieving the fixation of the three-layer slag removal pan 25. At the same time, the three-layer slag removal pan 25 can be synchronously driven to rotate by the slag removal motor 23, so that the slag removal pan 25 can remove the slag leaked onto the disc surface. The center position of the upper and lower slag removal pans 25 is provided with a socket, and the lower pipe mouth of the first discharge pipe 11 passes through the socket of the upper and lower slag removal pans 25 and extends to the upper disc surface of the third layer slag removal pan 25. The first discharge pipe 11 is provided with a plurality of overflow pipes 111 at positions corresponding to the upper and lower slag-discarding pans 25. The plurality of overflow pipes 111 are evenly arranged along the circumferential direction. The lower pipe opening of the first discharge pipe 11 is provided with a plurality of discharge notches 112 along the circumferential direction. The plurality of discharge notches 112 and the disk surface of the third-layer slag-discarding pan 25 form a discharge notch 112. After the slag in the slag pool 1 flows through the first discharge pipe 11, it is discharged from each overflow pipe 111 and the discharge opening to the corresponding slag-discarding pan 25. The slag is converted from a large slag body into a small slag body, thereby achieving the first-level cutting of the slag.

[0043] Combine Figure 7 In this embodiment, the slag plate 25 is provided with a plurality of circumferentially arranged slag grooves 251. Each slag groove 251 is arranged along the radial direction of the slag plate 25, and the depth of the slag groove 251 gradually deepens from the axis to the edge. When the slag falls from the first discharge pipe 11 onto the slag tray 25, the slag is in a molten state and flows into the slag trough 251. As the slag tray 25 rotates, the slag gradually moves from the axis to the edge of the slag tray 25 along the length direction of the slag trough 251 under centrifugal force, and the slag forms a spiral motion trajectory in the slag tray 25, thereby extending the time the slag stays on the slag tray 25, and the slag is uniformly accelerated in the slag trough 251; at the same time, since the centrifugal force of the slag tray 25 increases with the increase of the radius, the groove edge of the slag trough 251 can exert force on the slag, and the force gradually increases as the slag moves in the slag trough 251, so that the slag is gradually cut from small pieces of slag into uniform particles, realizing secondary cutting of the slag, avoiding slag accumulation, and improving the heat exchange efficiency between the slag and the heat exchange gas.

[0044] Combine Figure 5 and Figure 6 In this embodiment, each slag rejection pan 25 is surrounded by a high-speed airflow ring 26, for a total of three high-speed airflow rings 26. Counting downward, the first and second high-speed airflow rings 26 are fixedly connected, while the second high-speed airflow ring 26 is mounted on the support base 24 via support rods. The third high-speed airflow ring 26 has a smaller outer diameter than the first and second high-speed airflow rings 26 and is fixedly mounted on the support base 24. Each high-speed airflow ring 26 is circumferentially provided with an annular air outlet, which is connected to the three high-speed airflow rings 26 via air pipes (not shown) to supply air to the rings. After the slag is ejected from the slag rejection pan 25, the slag particles diffuse outward. High-speed cold air is then ejected from the high-speed airflow rings 26, which circumferentially shears the ejected slag, reducing the particle size and making the slag more uniform. This achieves a three-stage slag shearing process. This cooling air, upon contact with the smaller slag particles, accelerates heat exchange, producing high-temperature exhaust gas. In addition, after exchanging heat with the cooling air, the slag changes from a molten state to solid particles. The high-speed cold air impacts the granular slag, slowing its outward flight speed and causing it to fall to the bottom of the slag-sweeping shell 21 under its own gravity. This prevents the granular slag from colliding with the inner wall of the slag-sweeping shell 21, which would affect the service life of the slag-sweeping shell 21. At this time, the temperature of the solid particles drops from the original 1400°C to about 850°C, and they can be gradually dried during the slag-sweeping process.

[0045] Thus, the design of the slag-sweeping mechanism 2 of this embodiment can eliminate the crushing and drying steps of the slag compared to conventional processes, directly producing fine particles (particles with a diameter of 0.1 to 5 mm) by sweeping, eliminating intermediate steps and reducing power consumption and equipment maintenance costs. Furthermore, the steel slag particles produced in this embodiment are highly active and can be used directly as a cement admixture or roadbed material, reducing downstream grinding energy consumption (conventional processes require additional grinding to a specific surface area of ≥400 m² / kg). Dry processes such as centrifugal granulation do not require large amounts of cooling water, reducing water pump energy consumption and water treatment costs, and overall energy consumption is reduced by 30% to 50%.

[0046] Figure 1 Shows the structural diagram of the waste heat recovery mechanism 3, combined with Figure 1 The waste heat recovery mechanism 3 of this embodiment includes a pulsating fluidized bed 31, a low-temperature economizer 32, a dust removal heat exchanger 33, a superheater 34 and an evaporator 35. A second discharge pipe 212 is provided at the bottom of the slag removal shell 21. The second discharge pipe 212 is connected to the pulsating fluidized bed 31 to guide the solid steel slag that falls to the bottom of the slag removal shell 21 to the uniform air plate in the pulsating fluidized bed 31. Figure 8The bottom of the pulsating fluidized bed 31 is provided with an air inlet pipe 311, through which a second heat exchange gas is introduced into the pulsating fluidized bed 31. This second heat exchange gas is cooling air, which fluidizes the solid steel slag flowing through the uniform air plate. The solid steel slag gradually jumps from one end of the pulsating fluidized bed 31 to the other end, and fully contacts and exchanges heat with the cooling air introduced, thereby obtaining high-temperature gas. The air outlet of the pulsating fluidized bed 31 is connected to the air inlet of the low-temperature economizer 32. Softened water is introduced into the low-temperature economizer 32. The high-temperature gas enters the low-temperature economizer 32 to exchange heat with the softened water introduced into the low-temperature economizer 32. At this time, the softened water is heated to about 100°C. The water outlet of the low-temperature economizer 32 is connected to the water inlet of the dust removal heat exchanger 33, so that the softened water after heat exchange is introduced into the dust removal heat exchanger 33. The air outlet of the slag removal shell 21 communicates with the air inlet of the dust removal heat exchanger 33, exchanging heat with the softened water to further raise the softened water temperature (currently approximately 150°C). The dust removal heat exchanger 33 also removes dust, ensuring that the gas entering the atmosphere meets emission requirements. The air outlet of the dust removal heat exchanger 33 communicates with the air inlet of the superheater 34, which in turn communicates with the air inlet of the evaporator 35. The water outlet of the dust removal heat exchanger 33 communicates with the water inlet of the evaporator 35, and the steam outlet of the evaporator 35 communicates with the steam inlet of the superheater 34. After the softened water enters the evaporator 35, it is heated by the high-temperature exhaust gas flowing into the evaporator 35. The softened water evaporates into saturated steam, which is then passed into the superheater 34. The high-temperature exhaust gas further heats the saturated steam to form superheated steam (currently approximately 850°C). This superheated steam is then passed into the power generation mechanism 4 to perform work. It can be seen from this that in this embodiment, the high-temperature exhaust gas and solid steel slag discharged by the slag removal mechanism 2 can undergo multi-stage stepped heat exchange with the softened water in the waste heat recovery mechanism 3, thereby achieving full recovery of the slag waste heat and avoiding energy waste.

[0047] Figure 1 Shows a schematic diagram of the structure of the power generation mechanism 4, combined with Figure 1 The power generation mechanism 4 of this embodiment is a steam turbine. After the superheated steam is introduced into the steam turbine, it drives the rotor of the steam turbine to generate power. The steam after the power generation enters the condenser and becomes condensed water. The drain outlet of the condenser is connected to the low-temperature economizer 32 to pass the condensed water into the low-temperature economizer 32, thereby realizing a closed loop of the water circuit.

[0048] Thus, the provision of waste heat recovery mechanism 3 in this embodiment minimizes energy loss during the heat exchange process, thereby increasing the power generation capacity of power generation mechanism 4. It also avoids waste of water and energy. Compared to dry processes, there is no wastewater discharge, thus avoiding the energy consumption and pollution associated with water-quenched slag dehydration.

[0049] Figure 9 、 Figure 10 and Figure 11Shows a schematic diagram of the structure of the dust removal heat exchanger 33, combined with Figure 9 、 Figure 10 and Figure 11 The dust removal heat exchanger 33 of this embodiment includes a dust removal shell 331, a separation cone 332, a guide pipe 333, a dust collecting box 334, a high-temperature economizer 335 and a planetary feeder 336. The separation cone 332 and the guide pipe 333 are sequentially arranged in the dust removal shell 331 from top to bottom, the dust collecting box 334 and the planetary feeder 336 are sequentially arranged at the bottom of the dust removal shell 331 from top to bottom, and the high-temperature economizer 335 is mounted outside the dust collecting box 334. Figure 10 An air inlet pipe 3311 is provided on the outer wall of the top end of the dust removal housing 331. The high-temperature exhaust gas entering through the air inlet pipe 3311 can flow tangentially into the dust removal housing 331 and rotate at high speed along the inner wall of the dust removal housing 331. Since the high-temperature exhaust gas contains not only high-temperature air but also tiny particles of steel slag, the high-temperature exhaust gas generates centrifugal force when rotating at high speed. The centrifugal force on the steel slag particles is much greater than the gravity and inertia force, and the centrifugal force on the steel slag particles and the gas is different in magnitude. The steel slag particles collide with the inner wall of the dust removal housing 331 and fall, while the high-speed airflow continues to flow downward in a spiral along the inner wall of the dust removal housing 331. Therefore, the tiny steel slag particles can be separated from the airflow with high separation efficiency, thereby achieving dust removal of the high-temperature exhaust gas.

[0050] Combine Figure 11 The separation cone 332 is provided with an upper and lower stages, and a gap is left between each stage of the separation cone 332 and the inner wall of the dust removal shell 331, wherein the radius of the upper separation cone 332 is smaller than the radius of the lower separation cone 332. When the slag particles are separated from the high-speed airflow, the slag particles flow downward along the inner wall of the dust removal shell 331, and the slag particles pass through the gap between the separation cone 332 and the dust removal shell 331, and flow into the dust collecting box 334 through the guide pipe 333, while the high-speed airflow is separated by the separation cone 332. Such a design can effectively prevent the settled slag particles from being re-rolled up by the airflow, thereby improving the separation efficiency, especially for slag particles below 10μm, the separation effect is more significant.

[0051] Combine Figure 11An annular airway 337 is formed between the flow guide tube 333 and the inner wall of the dust removal housing 331. The inner wall of the flow guide tube 333 is provided with an array of exhaust holes 3331, thereby connecting the interior of the flow guide tube 333 with the annular airway 337. An exhaust pipe 3312 is provided in the middle section of the dust removal housing 331, communicating with the annular airway 337. The filtered high-temperature exhaust gas flows from the exhaust holes 3331 of the flow guide tube 333 to the annular airway 337 and is then discharged through the exhaust pipe 3312. This design allows clean gas to enter the rear flue for heat exchange, preventing large amounts of particulate matter in the flue gas from accelerating wear on the heating surface. The water outlet of the low-temperature economizer 32 is connected to the water inlet of the high-temperature economizer 335, so that the softened water entering the high-temperature economizer 335 can exchange heat with the steel slag particles in the dust box 334. The water outlet of the high-temperature economizer 335 is connected to the water inlet of the evaporator 35, so that the softened water after heat exchange can be passed into the evaporator 35. When a certain amount of steel slag particles is stored in the dust box 334, the planetary feeder 336 is activated to discharge the stored steel slag particles.

[0052] The following combination Figures 1 to 11 The working principle and workflow of the steel slag granulation waste heat recovery system of the present invention are described in detail.

[0053] Step 1, determining the slag discharge amount of the slag pool 1: the linear drive unit drives the valve core 132 to move through the connecting rod 131, the inner diameter of the annular discharge channel changes, and the slag discharge amount in the slag pool 1 is adjusted as required.

[0054] Step 2, slag removal on the slag removal plate 25: the slag in the slag pool 1 flows through the first discharge pipe 11, the overflow pipe 111 and the discharge notch 112, and then flows onto the three-layer slag removal plate 25. As the slag removal plate 25 rotates, the slag gradually moves from the plate center to the edge of the slag removal plate 25 along the length direction of the slag removal groove 251 under centrifugal force, and the slag forms a spiral motion trajectory in the slag removal plate 25. The groove edge of the slag removal groove 251 exerts force on the slag, and the force gradually increases as the slag moves in the slag removal groove 251, so that the slag is gradually cut from small pieces of slag into uniform particles.

[0055] Step 3, airflow ring cutting: After the slag is thrown out by the slag-throwing plate 25, the slag particles spread outward. At the same time, the high-speed airflow ring 26 sprays high-speed cold air, which ring cuts the thrown slag, making the slag particle size smaller and the slag particle size more uniform. At this time, high-temperature exhaust gas and solid steel slag are obtained;

[0056] Step 4, slag heat exchange: solid steel slag is introduced to the uniform air plate in the pulsating fluidized bed 31, and a second heat exchange gas is introduced into the pulsating fluidized bed 31 through the air inlet pipe 311. The second heat exchange gas is cooling air, which is used to fluidize the solid steel slag flowing through the uniform air plate. The solid steel slag gradually jumps from one end of the pulsating fluidized bed 31 to the other end, and is fully in contact with the introduced cooling air for heat exchange to obtain high-temperature gas; the high-temperature gas is introduced into the low-temperature economizer 32 to exchange heat with the softened water introduced into the low-temperature economizer 32. At this time, the softened water is heated to about 100°C.

[0057] Step 5, high-temperature exhaust gas dust removal: The high-temperature exhaust gas flows tangentially into the dust removal heat exchanger 33 and rotates at high speed along the inner wall of the dust removal shell 331. The high-temperature exhaust gas generates centrifugal force when rotating at high speed. The centrifugal force on the slag particles is much greater than the gravity and inertia force, and the centrifugal force on the slag particles is different from that on the gas. The slag particles hit the inner wall of the dust removal shell 331 and fall down, while the high-speed airflow continues to flow downward in a spiral along the inner wall of the dust removal shell 331, so that the tiny slag particles can be separated from the airflow; the slag particles flow downward along the inner wall of the dust removal shell 331, and the slag particles pass through the gap between the separation cone 332 and the dust removal shell 331, and flow into the dust collecting box 334 through the guide pipe 333, and the high-speed airflow is separated by the separation cone 332, thereby achieving dust removal. The filtered high-temperature exhaust gas is discharged from the exhaust hole 3331 of the guide pipe 333 , the annular air passage 337 and the exhaust pipe 3312 and flows into the superheater 34 , and then flows from the superheater 34 into the evaporator 35 .

[0058] Step 6: High-temperature exhaust gas heat exchange: Softened water flowing out of the low-temperature economizer 32 flows into the high-temperature economizer 335, where it exchanges heat with the slag particles in the dust box 334. The softened water's temperature rises to approximately 150°C. The softened water flowing out of the high-temperature economizer 335 then flows into the evaporator 35, where it is heated by the high-temperature exhaust gas flowing into the evaporator 35. The softened water evaporates into saturated steam, which is then passed into the superheater 34. The high-temperature exhaust gas further heats the saturated steam to form superheated steam, reaching a temperature of approximately 850°C.

[0059] Step 7, power generation: superheated steam is passed into the steam turbine to drive the turbine rotor to generate power. The steam after work enters the condenser and turns into condensed water, which is passed into the low-temperature economizer 32 to realize the closed loop of the water circuit.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. Steel slag granulation waste heat recovery system, characterized by: include: a slag pool storing molten slag; The slag throwing mechanism is connected to the slag pool and can throw the slag discharged from the slag pool to the surrounding area, so that the thrown slag exchanges heat with the first heat exchange gas introduced to obtain high-temperature waste gas and solid steel slag; The waste heat recovery mechanism is connected to the slag rejection mechanism and is used for exchanging heat with the high-temperature exhaust gas and solid steel slag to recover the waste heat of the high-temperature exhaust gas and solid steel slag.

2. The steel slag granulation waste heat recovery system according to claim 1, characterized in that: The slag removal mechanism includes at least one slag removal plate that can remove the slag; the slag removal plate is provided with a plurality of circumferentially arranged slag removal grooves, and the slag removal grooves are configured to apply force to the slag when the slag moves along the length direction of the slag removal groove under centrifugal force, so that the slag is cut into particles.

3. The steel slag granulation waste heat recovery system according to claim 2, characterized in that: A high-speed airflow ring is provided outside each layer of the slag-sweeping plate. The high-speed airflow ring is provided with an annular air outlet along the circumferential direction. The high-speed airflow ring discharges air to perform circular cutting on the slag being swished out.

4. The steel slag granulation waste heat recovery system according to claim 1, characterized in that: The waste heat recovery mechanism includes a pulsating fluidized bed, a low-temperature economizer, a dust removal heat exchanger, a superheater and an evaporator. The pulsating fluidized bed is connected to the slag rejection mechanism. A second heat exchange gas is introduced into the pulsating fluidized bed to exchange heat with the solid steel slag flowing into the pulsating fluidized bed to obtain high-temperature gas; the high-temperature gas is introduced into the low-temperature economizer to exchange heat with the softened water introduced into the low-temperature economizer; the high-temperature exhaust gas flowing out of the slag rejection mechanism flows through the dust removal heat exchanger, superheater and evaporator in sequence, and the softened water flowing out of the low-temperature economizer flows through the dust removal heat exchanger, evaporator and superheater in sequence to exchange heat with the high-temperature exhaust gas step by step to obtain superheated steam.

5. The steel slag granulation waste heat recovery system according to claim 4, characterized in that: It also includes a power generation mechanism communicated with the superheater, and the superheated steam is passed into the power generation mechanism to generate power.

6. The steel slag granulation waste heat recovery system according to claim 5, characterized in that: The power generation mechanism is connected to the low-temperature economizer so that the softened water after work is passed into the low-temperature economizer.

7. The steel slag granulation waste heat recovery system according to claim 4, characterized in that: The dust removal heat exchanger includes a dust removal shell, a separation cone, a guide pipe, a dust collecting box and a high-temperature economizer. The separation cone and the guide pipe are arranged in the dust removal shell from top to bottom, the dust collecting box is arranged at the bottom of the dust removal shell, and the high-temperature economizer is mounted outside the dust collecting box; the high-temperature exhaust gas flows tangentially into the dust removal shell to separate the high-temperature gas and steel slag particles, and the separation cone isolates the high-temperature gas and steel slag particles so that the steel slag particles fall into the dust collecting box; an annular airway is formed between the guide pipe and the inner wall of the dust removal shell, which is connected to the inside of the guide pipe, and the separated high-temperature gas flows into the superheater in turn from the guide pipe and the annular airway; the softened water discharged from the low-temperature economizer is passed into the high-temperature economizer to exchange heat with the steel slag particles.

8. The steel slag granulation waste heat recovery system according to claim 1, characterized in that: At least two levels of anti-condensation baffles are arranged in the slag pool along the feeding direction and are staggered up and down.

9. The steel slag granulation waste heat recovery system according to claim 1, characterized in that: The discharge port of the slag pool is provided with a flow control valve for controlling the discharge amount of the slag pool.

10. The steel slag granulation waste heat recovery system according to claim 9, characterized in that: The flow control valve includes a linear drive part, a connecting rod and a valve core. The cross section of the valve core is trapezoidal. The valve core is inserted into the discharge port of the slag pool. One end of the connecting rod is connected to the valve core, and the other end is driven and connected to the linear drive part.

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