System and method for recovering heat energy from steelmaking slag

Abstract

The invention provides a system and method for recovering heat energy from steelmaking slag. The system comprises a thermoelectric conversion unit; the heat energy transmission pipeline is used for transmitting the collected hot air to the thermoelectric conversion unit; the high-temperature heat exchange system is connected with the heat energy transmission pipeline, and the high-temperature heat exchange system is configured to obtain high-temperature slag from the steel refining furnace and reduce the temperature of the high-temperature slag from 1500 DEG C to 900 DEG C; the high-temperature heat exchange system comprises a high-temperature-resistant heat collection bin, a slag bed and a slag breaking device; the slag bed and the slag breaking device are arranged in the heat collection bin, and the slag breaking device is used for breaking and moving high-temperature slag in a fluid state so that the high-temperature slag releases heat to form semi-fluid semi-solid slag; the heat collection bin is further connected with an air inlet unit. The air inlet unit continuously inputs inlet air into the heat collection bin, and air flow formed by the inlet air feeds heat in the heat collection bin into the heat energy transmission pipeline. According to the system, efficient waste heat utilization of a heat source at the temperature of 1500-500 DEG C is achieved.

Description

Technical Field

[0001] The present application relates to the field of heat recovery technology, and in particular to a system and method for recovering heat energy from steelmaking slag. Background Art

[0002] Existing methods for utilizing slag waste heat include heat extraction from molten iron, heat extraction from iron slag, heat extraction from pellets, and heat extraction from flue gas, but generally only heat sources with an initial temperature below 500 degrees Celsius can be recovered, and the heat source is mainly extracted by flue gas convection, and it is impossible to directly and efficiently extract heat from slag with a temperature above 500 degrees Celsius. In addition, there are also problems such as the inability to control heat release and too long heat extraction time, which leads to heat loss and the inability to maximize the utilization of heat energy. Summary of the invention

[0003] In view of this, the technical problem to be solved by the present application is to provide a system and method for recovering heat energy from steelmaking slag, which can more efficiently extract heat from 1500℃-500℃ slag, so as to solve the problem of insufficient heat utilization and low efficiency of high-temperature slag in the prior art.

[0004] To solve the above problems, in one aspect of the present application, a system for recovering heat energy from steelmaking slag is proposed, comprising:

[0005] A thermoelectric conversion unit, including a boiler and a steam turbine generator, is used to convert thermal energy into electrical energy;

[0006] A heat energy transmission pipeline, used to transmit the collected hot air to the thermoelectric conversion unit;

[0007] A high-temperature heat exchange system is connected to the heat energy transmission pipeline, and the high-temperature heat exchange system is configured to obtain high-temperature slag from the steelmaking furnace and reduce its temperature from 1500°C to 900°C; the high-temperature heat exchange system includes a high-temperature resistant heat collection bin, a slag bed and a slag breaking device; the slag bed and the slag breaking device are arranged in the heat collection bin, and the slag breaking device breaks and moves the high-temperature slag in a fluid state to release heat to form a semi-fluid and semi-solid slag; the heat collection bin is also connected to an air intake unit; the air intake unit continuously inputs air into the heat collection bin, and the airflow formed by the air intake sends the heat in the heat collection bin into the heat energy transmission pipeline; and

[0008] The medium-temperature heat exchange system is connected to the heat energy transmission pipeline; the medium-temperature heat exchange system is configured to receive the slag formed by the high-temperature heat exchange system and further reduce its temperature to 300°C; the medium-temperature heat exchange system includes a rotary kiln, which continuously rotates and beats the slag inside it, so that the slag is further broken and releases heat, and the heat energy in the rotary kiln is transmitted to the heat energy transmission pipeline.

[0009] Another aspect of the present application provides a method for recovering heat energy from steelmaking slag, comprising:

[0010] The high-temperature slag is obtained from the steelmaking furnace and sent to the high-temperature heat exchange system, which is configured to reduce its temperature from 1500°C to 900°C; the high-temperature heat exchange system includes a high-temperature resistant heat collection bin, a slag bed and a slag breaking device; the slag bed and the slag breaking device are arranged in the heat collection bin, and the slag breaking device breaks and moves the high-temperature slag in a fluid state to release heat to form a semi-fluid and semi-solid slag; the heat collection bin is also connected to an air intake unit; the air intake unit continuously inputs air into the heat collection bin, and the airflow formed by the air intake sends the heat in the heat collection bin to the heat energy transmission pipeline and the connected thermoelectric conversion unit;

[0011] The slag obtained from the high-temperature heat exchange system is then poured into the medium-temperature heat exchange system, which is configured to reduce the temperature of the slag to 300°C; the medium-temperature heat exchange system includes a rotary kiln, which continuously rotates and beats the slag inside it, so that the slag is further broken and releases heat, and the heat energy in the rotary kiln is transmitted to the heat energy transmission pipeline and the connected thermoelectric conversion unit.

[0012] Another aspect of the present application provides a system for recovering heat energy from steelmaking slag, comprising:

[0013] A thermoelectric conversion unit, including a boiler and a steam turbine generator, is used to convert thermal energy into electrical energy;

[0014] A heat energy transmission pipeline, used to transmit the collected hot air to the thermoelectric conversion unit;

[0015] A high-temperature heat exchange system is connected to the heat energy transmission pipeline. The high-temperature heat exchange system is configured to obtain high-temperature slag from a steelmaking furnace and reduce its temperature from 1500°C to 900°C; the high-temperature heat exchange system includes a high-temperature resistant heat collection bin, a slag bed and a slag breaking device; the slag bed and the slag breaking device are arranged in the heat collection bin, and the slag breaking device breaks and moves the high-temperature slag in a fluid state to release heat and form semi-fluid and semi-solid slag; the heat collection bin is also connected to an air intake unit; the air intake unit continuously inputs air into the heat collection bin, and the airflow formed by the air intake sends the heat in the heat collection bin into the heat energy transmission pipeline.

[0016] The system and method for recovering heat energy from steelmaking slag provided in the present application achieves rapid release of heat in the slag by crushing and hoisting the high-temperature slag arranged in a closed heat collection bin, and then carries the released heat to a thermoelectric conversion unit through an airflow for power generation. Since the heat is released in a concentrated manner through the process of crushing and hoisting the slag, the released heat has a high intensity and can be used efficiently by the boiler, and the rate of crushing and heat extraction is controllable, thereby facilitating thermal management. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Shown is a schematic diagram of the composition of a system for recovering heat energy from steelmaking slag provided by one embodiment of the present application;

[0018] Figure 2 Shown is a high-temperature heat exchange system architecture diagram provided by an embodiment of the present application;

[0019] Figure 3 The figure shows a top view of a slag breaking device provided by one embodiment of the present application;

[0020] Figure 4 Shown is a three-dimensional schematic diagram of a slag breaking device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer and more understandable, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0022] Words related to directions in the present application, such as up, down, top, bottom, inside, outside, high, and low, are based on the position of the high-temperature heat exchange system or the medium-temperature heat exchange system under normal use.

[0023] In the present application, high temperature refers to a slag temperature between 1500-900°C; medium temperature refers to a slag temperature between 900-300°C; and low temperature refers to a slag temperature below 300°C.

[0024] In one aspect of the present application, a system for recovering heat energy from steelmaking slag is provided, comprising:

[0025] A thermoelectric conversion unit, including a boiler and a steam turbine generator, is used to convert thermal energy into electrical energy;

[0026] A heat energy transmission pipeline, used to transmit the collected hot air to the thermoelectric conversion unit;

[0027] A high-temperature heat exchange system is connected to the heat energy transmission pipeline, and the high-temperature heat exchange system is configured to obtain high-temperature slag from the steelmaking furnace and reduce its temperature from 1500°C to 900°C; the high-temperature heat exchange system includes a high-temperature resistant heat collection bin, a slag bed and a slag breaking device; the slag bed and the slag breaking device are arranged in the heat collection bin, and the slag breaking device breaks and moves the high-temperature slag in a fluid state to release heat to form a semi-fluid and semi-solid slag; the heat collection bin is also connected to an air intake unit; the air intake unit continuously inputs air into the heat collection bin, and the airflow formed by the air intake sends the heat in the heat collection bin into the heat energy transmission pipeline; and

[0028] The medium-temperature heat exchange system is connected to the heat energy transmission pipeline; the medium-temperature heat exchange system is configured to receive the slag formed by the high-temperature heat exchange system and further reduce its temperature to 300°C; the medium-temperature heat exchange system includes a rotary kiln, which continuously rotates and beats the slag inside it, so that the slag is further broken and releases heat, and the heat energy in the rotary kiln is transmitted to the heat energy transmission pipeline.

[0029] In at least one embodiment, the slag breaking device is arranged on the slag bed, including a roller, a balance frame, a linear guide, a cooling unit, and a first drive unit and a second drive unit; the roller is arranged on the balance frame, the first drive unit drives the balance frame to drive the roller to reciprocate along the linear guide, and the second drive unit drives the roller to roll clockwise or counterclockwise to crush the high-temperature slag and push the slag to the target area.

[0030] In at least one embodiment, the outer periphery of the roller shaft is covered with roller teeth, and the roller shaft and the roller teeth are cast from a high-temperature resistant alloy and can withstand 1500° C. or above.

[0031] In at least one embodiment, a gear set and a guide wheel are provided on the balance frame, and the gear set is used to transmit the power of the second drive unit to the roller shaft to rotate it; the guide wheel cooperates with the linear guide rail, and under the drive of the first drive unit, the guide wheel moves along the linear rail.

[0032] In at least one embodiment, the cooling unit continuously sprays and cools the roller, the balance frame, the gear set, the guide wheel and the linear guide rail so that their temperature is no higher than 60°C.

[0033] At least one embodiment further includes a low-temperature heat exchange system configured to receive the solid slag received from the rotary kiln, continue to extract the remaining heat and transfer the extracted heat to the heat energy transmission pipeline and the connected thermoelectric conversion unit.

[0034] In at least one embodiment, it also includes a conveying system, which is arranged between the high-temperature heat exchange system and the medium-temperature heat exchange system, and is used to transport the slag output from the high-temperature heat exchange system to the medium-temperature heat exchange system; the conveying system includes a conveyor belt and a bucket elevator, and the bucket elevator is arranged at the end of the conveyor belt, and is used to pour the slag from the conveyor belt into the rotary kiln.

[0035] In at least one embodiment, the heat energy transmission pipeline includes multiple branch pipelines and a main pipeline, and the high-temperature heat exchange system and the medium-temperature heat exchange system are respectively connected to a branch pipeline; the main pipeline is connected to the thermoelectric conversion unit.

[0036] At least one embodiment further includes a heat storage unit, which is disposed between the heat energy transmission pipeline and the thermoelectric conversion unit and is used to store energy that cannot be immediately used by the thermoelectric conversion unit.

[0037] At least one embodiment further includes a dust removal unit, which is disposed at the air flow outlet of the high-temperature heat exchange system and the medium-temperature heat exchange system and is used to remove dust from the air flow carrying heat to prevent dust from entering the heat energy transmission pipeline.

[0038] In at least one embodiment, a high-temperature heat exchange system and a medium-temperature heat exchange system are each provided with an independent heat collection chamber.

[0039] In at least one embodiment, the thermoelectric conversion unit includes multiple, the heat energy transmission pipeline is connected to the multiple thermoelectric conversion units through multiple branch pipelines, and each branch pipeline is provided with a switch so that the branch pipeline can selectively provide heat energy to the connected thermoelectric conversion unit.

[0040] Another aspect of the present application provides a method for recovering heat energy from steelmaking slag, comprising:

[0041] The high-temperature slag is obtained from the steelmaking furnace and sent to the high-temperature heat exchange system, which is configured to reduce its temperature from 1500°C to 900°C; the high-temperature heat exchange system includes a high-temperature resistant heat collection bin, a slag bed and a slag breaking device; the slag bed and the slag breaking device are arranged in the heat collection bin, and the slag breaking device breaks and moves the high-temperature slag in a fluid state to release heat to form a semi-fluid and semi-solid slag; the heat collection bin is also connected to an air intake unit; the air intake unit continuously inputs air into the heat collection bin, and the airflow formed by the air intake sends the heat in the heat collection bin to the heat energy transmission pipeline and the connected thermoelectric conversion unit;

[0042] The slag obtained from the high-temperature heat exchange system is then poured into the medium-temperature heat exchange system, which is configured to reduce the temperature of the slag to 300°C; the medium-temperature heat exchange system includes a rotary kiln, which continuously rotates and beats the slag inside it, so that the slag is further broken and releases heat, and the heat energy in the rotary kiln is transmitted to the heat energy transmission pipeline and the connected thermoelectric conversion unit.

[0043] In at least one embodiment, the slag obtained from the medium-temperature heat exchange system is further poured into the low-temperature heat exchange system to continue to extract the remaining heat and transfer the extracted heat to the heat energy transmission pipeline and the connected thermoelectric conversion unit.

[0044] In at least one embodiment, the slag breaking device is arranged on the slag bed, including a roller shaft, a balance frame, a linear guide rail, a cooling unit, and a first drive unit and a second drive unit; the roller shaft is arranged on the balance frame, the first drive unit drives the balance frame to drive the roller shaft to reciprocate along the linear guide rail, and the second drive unit drives the roller shaft to roll clockwise or counterclockwise to crush the high-temperature slag, and push the slag to the target area; the outer periphery of the roller shaft is covered with roller teeth, and the roller shaft and roller teeth are cast with high-temperature resistant alloy and can withstand 1500°C or above.

[0045] Another aspect of the present application provides a system for recovering heat energy from steelmaking slag, comprising:

[0046] A thermoelectric conversion unit, including a boiler and a steam turbine generator, is used to convert thermal energy into electrical energy;

[0047] A heat energy transmission pipeline, used to transmit the collected hot air to the thermoelectric conversion unit;

[0048] A high-temperature heat exchange system is connected to the heat energy transmission pipeline. The high-temperature heat exchange system is configured to obtain high-temperature slag from a steelmaking furnace and reduce its temperature from 1500°C to 900°C; the high-temperature heat exchange system includes a high-temperature resistant heat collection bin, a slag bed and a slag breaking device; the slag bed and the slag breaking device are arranged in the heat collection bin, and the slag breaking device breaks and moves the high-temperature slag in a fluid state to release heat and form semi-fluid and semi-solid slag; the heat collection bin is also connected to an air intake unit; the air intake unit continuously inputs air into the heat collection bin, and the airflow formed by the air intake sends the heat in the heat collection bin into the heat energy transmission pipeline.

[0049] In at least one embodiment, the slag breaking device is arranged on the slag bed, including a roller shaft, a balance frame, a linear guide rail, a cooling unit, and a first drive unit and a second drive unit; the outer periphery of the roller shaft is covered with roller teeth, and the roller shaft and the roller teeth are cast with a high-temperature resistant alloy and can withstand 1500°C or above; the roller shaft is arranged on the balance frame, and the first drive unit drives the balance frame to drive the roller shaft to reciprocate along the linear guide rail, and the second drive unit drives the roller shaft to roll clockwise or counterclockwise to crush the high-temperature slag and push the slag to the target area; the cooling unit continuously sprays and cools the roller shaft, the balance frame, the gear set, the guide wheel and the linear guide rail to make their temperature not higher than 60°C.

[0050] In at least one embodiment, a gear set and a guide wheel are provided on the balance frame, and the gear set is used to transmit the power of the second drive unit to the roller shaft to rotate it; the guide wheel cooperates with the linear guide rail, and under the drive of the first drive unit, the guide wheel moves along the linear rail.

[0051] The specific implementation process and technical effects of the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0052] like Figure 1The system for recovering heat energy from steelmaking slag provided by one of the embodiments of the present application as shown includes a high-temperature heat exchange system 100, a medium-temperature heat exchange system 200, and a low-temperature heat exchange system 300 and a plurality of thermoelectric conversion units, such as the thermoelectric conversion units 1-3 in the figure; wherein the high-temperature heat exchange system 100, the medium-temperature heat exchange system 200 and the low-temperature heat exchange system 300 can be independently operated in different spaces to realize flexible selection of sites and facilitate flexible arrangement according to needs; they can also be operated in coordination in the same space to reduce heat loss caused by transferring slag and improve heat extraction efficiency. The high-temperature heat exchange system 100, the medium-temperature heat exchange system 200, and the low-temperature heat exchange system 300 are directly connected or connected through a transmission system 400 to realize the closed transmission of slag from the previous system to the next system, and the transmission system can be a transfer tool or a transmission crawler. The thermoelectric conversion unit includes a boiler and a steam turbine generator, which are used to convert thermal energy into electrical energy. The specific working process thereof refers to the prior art; the high-temperature heat exchange system 100, the medium-temperature heat exchange system 200, and the low-temperature heat exchange system 300 are connected to the heat energy transmission pipeline 500 through a branch pipeline 501, and are connected to the corresponding thermoelectric conversion units to transmit the collected heat to the thermoelectric conversion unit for power generation. Optionally, the high-temperature heat exchange system 100, the medium-temperature heat exchange system 200, and the low-temperature heat exchange system 300 can be connected to the thermoelectric conversion unit through independent heat energy transmission pipelines 500.

[0053] like Figure 2 The high temperature heat exchange system 100 of one embodiment is shown, which includes a heat collection bin 50 resistant to high temperature, and a slag bed ( Figure 2The slag bed is used to place high-temperature slag with a temperature of up to 1500°C entering from the inlet. The slag breaking device 10 rolls, separates, crushes and moves the high-temperature slag in a fluid state arranged on the slag bed, so that the high-temperature slag releases heat. The air intake unit 20 continuously inputs gas into the heat collection bin 50 to form an airflow. After releasing the heat, the high-temperature slag changes from a fluid state to a semi-fluid and semi-solid slag. The released heat heats the intake air by thermal radiation, and at the same time forms a high-temperature airflow and moves it in the direction of the heat transmission pipeline. After dust removal by the dust removal unit 30, the airflow with heat flows from the heat transmission pipeline 500 to the connected thermoelectric conversion unit. As the high-temperature slag is continuously crushed and turned, the heat is released and gradually taken away. The temperature in the heat collection bin is finally reduced to about 900°C, and the slag is discharged and prepared to be sent to the medium-temperature heat exchange system 200. The medium temperature heat exchange system 200 is configured to receive the slag formed by the high temperature heat exchange system 100 and further reduce its temperature to 300°C; the medium temperature heat exchange system 200 includes a rotary kiln, which continuously rotates and beats the slag inside it, so that the slag is further broken and releases heat, and the heat energy in the rotary kiln is transmitted to the heat energy transmission pipeline. In order to prevent the heat that cannot be used in time from being wasted, a heat storage unit can be set at the output end of the high temperature heat exchange system 100 and the medium temperature heat exchange system 200, or a heat storage unit can be set between the heat energy transmission pipeline 500 and the thermoelectric conversion unit to store energy that cannot be used immediately by the thermoelectric conversion unit. The high temperature heat exchange system crushes and extracts heat at a speed of one bag of slag (30 tons) every 30 minutes, which greatly improves the efficiency of heat extraction. In the prior art, high temperature heat exchange cannot be performed by using flue gas to extract heat, and only slag waste heat below 900°C can be obtained.

[0054] like Figure 3 and Figure 4The slag-breaking device 10 is shown in a top view and a three-dimensional schematic diagram. The slag-breaking device 10 is arranged on the slag bed 60. The slag-breaking device 10 includes a roller shaft 11. The outer periphery of the roller shaft is covered with roller teeth 110. The roller shaft 11 and the roller teeth 110 are cast from a high-temperature resistant alloy, such as a manganese steel alloy, and can withstand 1500°C or above. The roller teeth 110 are arranged in multiple rows along the axis of the roller shaft, and the roller teeth in adjacent rows are arranged in a staggered manner, so that the roller teeth 110 can crush the slag to the greatest extent. The roller shaft 11 is arranged on a balance frame 16 to form a gantry shape; a gear set 12 for transmission is arranged on the side of the balance frame 16, and the gear set 12 is connected to the output end of the second drive unit 15, so that the second drive unit 15 can drive the roller shaft 11 to rotate clockwise or counterclockwise. The roller shaft 11 rotates clockwise or counterclockwise to crush or push the slag. The balance frame 16 is arranged on the linear guide rail 13 through the guide wheel 17. Under the action of the first driving unit 14, the guide wheel 17 drives the transmission shaft and the entire balance frame 16 and the roller 11 to move linearly, which is used to repeatedly crush and push the slag on the slag bed 60 to release heat from the slag. The roller 11 is also configured to climb a slope, which is convenient for handling the slope formed by the flow of slag. The cooling unit continuously sprays and cools the roller, balance frame, gear set, guide wheel and linear guide rail to keep their temperature no higher than 60°C.

[0055] A low-temperature heat exchange system is also set up after the medium-temperature heat exchange system as needed. The low-temperature heat exchange system is configured to receive the solid slag received from the rotary kiln, continue to extract the remaining heat and transfer the extracted heat to the heat energy transmission pipeline and the connected thermoelectric conversion unit. The low-temperature heat exchange system can achieve waste heat extraction by taking away the heat through a simple buried pipe (heat collecting pipe) method.

[0056] One embodiment also provides a method for recovering heat energy from steelmaking slag, comprising:

[0057] Step 1: Get the high-temperature slag from the steelmaking furnace and send it to the high-temperature heat exchange system. The high-temperature heat exchange system is configured to reduce its temperature from 1500℃ to 900℃; the high-temperature heat exchange system includes a high-temperature resistant heat collection bin, a slag bed and a slag breaking device; the slag bed and the slag breaking device are arranged in the heat collection bin, and the slag breaking device breaks and moves the high-temperature slag in a fluid state to release heat and form semi-fluid and semi-solid slag; the heat collection bin is also connected to an air intake unit; the air intake unit continuously inputs air into the heat collection bin, and the airflow formed by the air intake sends the heat in the heat collection bin into the heat energy A transmission pipeline and a connected thermoelectric conversion unit; wherein, a slag breaking device is arranged on a slag bed, and comprises a roller shaft, a balancing frame, a linear guide rail, a cooling unit, and a first drive unit and a second drive unit; the roller shaft is arranged on the balancing frame, the first drive unit drives the balancing frame to drive the roller shaft to reciprocate along the linear guide rail, and the second drive unit drives the roller shaft to roll clockwise or counterclockwise to crush the high-temperature slag, and push the slag to a target area; the outer periphery of the roller shaft is covered with roller teeth, and the roller shaft and roller teeth are cast with a high-temperature resistant alloy and can withstand 1500°C or above.

[0058] The second part: pouring the slag obtained from the high-temperature heat exchange system into the medium-temperature heat exchange system, which is configured to reduce the temperature of the slag to 300°C; the medium-temperature heat exchange system includes a rotary kiln, which continuously rotates and beats the slag inside it, so that the slag is further broken and releases heat, and the heat energy in the rotary kiln is transmitted to the heat energy transmission pipeline and the connected thermoelectric conversion unit.

[0059] A third step may also be included as needed: pouring the slag obtained from the medium-temperature heat exchange system into the low-temperature heat exchange system, continuing to extract the remaining heat and transferring the extracted heat to the heat energy transmission pipeline and the connected thermoelectric conversion unit.

[0060] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the present invention is not limited thereby. A person skilled in the art may implement the present invention in a variety of variations without departing from the scope and essence of the present invention, such as using a feature of one embodiment to obtain another embodiment. Any modification, equivalent substitution and improvement made within the technical concept of the present invention shall be within the scope of the present invention.

Claims

1. A system for recovering heat energy from steelmaking slag, comprising: A thermoelectric conversion unit, including a boiler and a steam turbine generator, is used to convert thermal energy into electrical energy; A heat energy transmission pipeline, used to transmit the collected hot air to the thermoelectric conversion unit; A high-temperature heat exchange system is connected to the heat energy transmission pipeline, and the high-temperature heat exchange system is configured to obtain high-temperature slag from a steelmaking furnace and reduce its temperature from 1500°C to 900°C; the high-temperature heat exchange system includes a high-temperature resistant heat collection bin, a slag bed and a slag breaking device; the slag bed and the slag breaking device are arranged in the heat collection bin, and the slag breaking device breaks and moves the high-temperature slag in a fluid state to release heat to form semi-fluid and semi-solid slag; the heat collection bin is also connected to an air intake unit; the air intake unit continuously inputs air into the heat collection bin, and the airflow formed by the air intake sends the heat in the heat collection bin into the heat energy transmission pipeline; and A medium-temperature heat exchange system is connected to the heat energy transmission pipeline; the medium-temperature heat exchange system is configured to receive the slag formed by the high-temperature heat exchange system and further reduce its temperature to 300°C; the medium-temperature heat exchange system includes a rotary kiln, which continuously rotates and beats the slag inside it, so that the slag is further broken and releases heat, and the heat energy in the rotary kiln is transmitted to the heat energy transmission pipeline.

2. The system according to claim 1, characterized in that: The slag breaking device is arranged on the slag bed, and includes a roller, a balance frame, a linear guide, a cooling unit, and a first drive unit and a second drive unit; the roller is arranged on the balance frame, the first drive unit drives the balance frame to drive the roller to reciprocate along the linear guide, and the second drive unit drives the roller to roll clockwise or counterclockwise to crush the high-temperature slag and push the slag to the target area.

3. The system according to claim 2, characterized in that: The outer periphery of the roller shaft is covered with roller teeth. The roller shaft and the roller teeth are cast from a high-temperature resistant alloy and can withstand 1500° C. or above.

4. The system according to claim 2, characterized in that: The balancing frame is provided with a gear set and a guide wheel, wherein the gear set is used to transmit the power of the second driving unit to the roller shaft to rotate it; the guide wheel cooperates with the linear guide rail, and under the drive of the first driving unit, the guide wheel moves along the linear rail.

5. The system according to claim 2, characterized in that: The cooling unit continuously sprays and cools the roller, balance frame, gear set, guide wheel and linear guide rail to control their temperature to be no higher than 60°C.

6. The system according to claim 1, characterized in that: It also includes a low-temperature heat exchange system configured to receive the solid slag received from the rotary kiln, continue to extract residual heat and transfer the extracted heat to the heat energy transmission pipeline and the connected thermoelectric conversion unit.

7. The system according to claim 1, characterized in that: It also includes a conveying system, which is arranged between the high-temperature heat exchange system and the medium-temperature heat exchange system, and is used to transport the slag output from the high-temperature heat exchange system to the medium-temperature heat exchange system; the conveying system includes a conveyor belt and a bucket elevator, and the bucket elevator is arranged at the end of the conveyor belt, and is used to pour the slag from the conveyor belt into the rotary kiln.

8. The system according to claim 1, characterized in that: The heat energy transmission pipeline includes a plurality of branch pipelines and a main pipeline. The high-temperature heat exchange system and the medium-temperature heat exchange system are respectively connected to a branch pipeline; and the main pipeline is connected to the thermoelectric conversion unit.

9. The system according to claim 1, characterized in that: It also includes a heat storage unit, which is arranged between the heat energy transmission pipeline and the thermoelectric conversion unit and is used to store energy that cannot be used immediately by the thermoelectric conversion unit.

10. The system according to claim 1, characterized in that: It also includes a dust removal unit, which is arranged at the air flow outlets of the high-temperature heat exchange system and the medium-temperature heat exchange system and is used to remove dust from the air flow carrying heat to prevent dust from entering the heat energy transmission pipeline.

11. The system according to claim 1, characterized in that: The high-temperature heat exchange system and the medium-temperature heat exchange system are each provided with an independent heat collection chamber.

12. The system according to claim 1, characterized in that: The thermoelectric conversion units include a plurality of them, the heat energy transmission pipeline is connected to the plurality of thermoelectric conversion units through a plurality of branch pipelines, and each branch pipeline is provided with a switch so that the branch pipeline can selectively provide heat energy to the connected thermoelectric conversion unit.

13. A method for recovering heat energy from steelmaking slag, applied to the system of claim 1, comprising: The high-temperature slag is obtained from the steelmaking furnace and sent to the high-temperature heat exchange system, and the high-temperature heat exchange system is configured to reduce its temperature from 1500°C to 900°C; the high-temperature heat exchange system includes a high-temperature resistant heat collection bin, a slag bed and a slag breaking device; the slag bed and the slag breaking device are arranged in the heat collection bin, and the slag breaking device breaks and moves the high-temperature slag in a fluid state to release heat to form a semi-fluid and semi-solid slag; the heat collection bin is also connected to an air intake unit; the air intake unit continuously inputs air into the heat collection bin, and the airflow formed by the air intake sends the heat in the heat collection bin into the heat energy transmission pipeline and the connected thermoelectric conversion unit; The slag obtained from the high-temperature heat exchange system is then poured into a medium-temperature heat exchange system, which is configured to reduce the temperature of the slag to 300°C; the medium-temperature heat exchange system includes a rotary kiln, which continuously rotates and beats the slag inside it, so that the slag is further broken up and releases heat, and the heat energy in the rotary kiln is transmitted to the heat energy transmission pipeline and the connected thermoelectric conversion unit.

14. The method according to claim 13, characterized in that Further including: The slag obtained from the medium-temperature heat exchange system is poured into the low-temperature heat exchange system to continue to extract the remaining heat and transfer the extracted heat to the heat energy transmission pipeline and the connected thermoelectric conversion unit.

15. The method according to claim 13, characterized in that: The slag breaking device is arranged on the slag bed, and includes a roller, a balance frame, a linear guide, a cooling unit, and a first drive unit and a second drive unit; the roller is arranged on the balance frame, the first drive unit drives the balance frame to drive the roller to reciprocate along the linear guide, and the second drive unit drives the roller to roll clockwise or counterclockwise to crush the high-temperature slag and push the slag to the target area; the outer periphery of the roller is covered with roller teeth, and the roller and roller teeth are cast with high-temperature resistant alloy and can withstand 1500°C or above.

16. A system for recovering heat energy from steelmaking slag, comprising: A thermoelectric conversion unit, including a boiler and a steam turbine generator, is used to convert thermal energy into electrical energy; A heat energy transmission pipeline, used for transmitting the collected hot air to the thermoelectric conversion unit; A high-temperature heat exchange system is connected to the heat energy transmission pipeline, and the high-temperature heat exchange system is configured to obtain high-temperature slag from a steelmaking furnace and reduce its temperature from 1500°C to 900°C; the high-temperature heat exchange system includes a high-temperature resistant heat collection bin, a slag bed and a slag breaking device; the slag bed and the slag breaking device are arranged in the heat collection bin, and the slag breaking device breaks and moves the high-temperature slag in a fluid state to release heat and form semi-fluid and semi-solid slag; the heat collection bin is also connected to an air intake unit; the air intake unit continuously inputs air into the heat collection bin, and the airflow formed by the air intake sends the heat in the heat collection bin into the heat energy transmission pipeline.

17. The system according to claim 16, characterized in that: The slag breaking device is arranged on the slag bed, and includes a roller shaft, a balance frame, a linear guide rail, a cooling unit, and a first drive unit and a second drive unit; the outer periphery of the roller shaft is covered with roller teeth, and the roller shaft and roller teeth are cast with a high-temperature resistant alloy and can withstand 1500°C or above; the roller shaft is arranged on the balance frame, and the first drive unit drives the balance frame to drive the roller shaft to reciprocate along the linear guide rail, and the second drive unit drives the roller shaft to roll clockwise or counterclockwise to crush the high-temperature slag and push the slag to the target area; the cooling unit continuously sprays and cools the roller shaft, the balance frame, the gear set, the guide wheel and the linear guide rail to make their temperature not higher than 60°C.

18. The system according to claim 17, characterized in that: The balancing frame is provided with a gear set and a guide wheel, wherein the gear set is used to transmit the power of the second driving unit to the roller shaft to rotate it; the guide wheel cooperates with the linear guide rail, and under the drive of the first driving unit, the guide wheel moves along the linear rail.

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