Rapid cooling dry processing device for blast furnace slag drums for waste heat recovery

Abstract

Rapidly cooling dry processing device for blast furnace slag drums for waste heat recovery, comprising a blast furnace slag slot mounted on a support, several sets of cooling pelletizing drums, and a heat exchanger. The cooling pelletizing drum has inner and outer cylinders, a cooling coil, and a heat transfer medium. The enclosed space between the inner and outer cylinders is filled with the heat transfer medium, and the cooling coil is completely isolated from the slag and buried in the heat transfer medium within the enclosed space of the inner and outer cylinders.When the device is running, the drum rotates and the molten slag flows naturally downwards from the adjustable-width groove opening at the bottom of the blast furnace slag slot, adhering to the surface of the outer cylinder. Heat is transferred by the heat transfer medium between the inner and outer drums to the cooling coil embedded within them and dissipated by the coolant in the cooling coil. The slag cools rapidly, becoming glassy, ​​and is then pressed and pulverized by the meshing outer cylinders of the gear rollers before entering the heat exchanger for waste heat recovery.If the invention works, the slag vitrification and slag granulation collection processes will be carried out simultaneously to achieve continuous production; molten slag can be efficiently recycled, effectively reducing the waste of valuable waste heat resources from liquid molten slag.

Description

A blast furnace slag drum rapid cooling dry treatment device for waste heat recovery Technical Field

[0001] The present invention belongs to the technical field of metallurgical high-temperature slag treatment, and particularly relates to a blast furnace slag drum rapid cooling dry treatment device for separating slag from water, wherein a cooling pipe does not directly contact the slag and is used for waste heat recovery. Background Art

[0002] Blast furnace slag is a major byproduct of the steel and metallurgical industry. Under current production processes, over 0.3 tons of blast furnace slag is generated for every ton of pig iron produced. Its temperature ranges from approximately 1450°C to 1550°C, and each ton of slag contains approximately 1.8 MJ of waste heat that can be recycled. China is currently the world's largest steel producer. In 2020, the country's total pig iron production reached 887.524 million tons. Based on the industry average, an estimated 266 million tons of slag were generated, containing the equivalent heat of 16.365 million tons of standard coal (1 ton of standard coal produces 29,307.6 kJ). Effectively recycling the heat energy in high-temperature slag could reduce atmospheric pollutants such as CO₂, SO₂, and H₂S by tens of thousands of tons. Currently, there are two main methods for treating high-temperature slag: wet and dry. The wet method, or water quenching, is the most widely used. While this method offers advantages such as small particle size and high glass content, it wastes significant amounts of water and high-grade heat energy, while also generating sulfur-containing gases and polluting the environment. Dry processes, including cup, drum, and turntable methods, primarily utilize centrifugal force and air cooling to granulate the slag. Traditional dry processing methods suffer from poor final product quality due to low air cooling efficiency and uncontrollable high-temperature slag flow. The content of glass particles suitable for cement production is relatively low, and the equipment structure is complex and unstable.

[0003] Summary of the Invention

[0004] In response to the deficiencies in the prior art, the present invention provides a blast furnace slag drum rapid cooling dry treatment device for waste heat recovery. When the device is in operation, the high-temperature slag flows downward through the notch at the bottom of the blast furnace slag trough and adheres to the cooling granulation drum below. The cooling granulation drum is composed of an inner and outer cylinder, the ends of the inner and outer cylinders are sealed, and the closed cavity in the middle is filled with a heat-conducting medium. The coolant flows in the closed cooling coil, and the cooling coil is buried in the heat-conducting medium between the inner and outer cylinders. The high-temperature slag adheres to the surface of the outer cylinder, and the heat is transferred from the heat-conducting medium between the inner and outer cylinders to the cooling pipe buried therein, and is carried away by the coolant in the cooling pipe. The high-temperature slag is rapidly cooled to about 600°C and forms a glassy state. The cooling granulation drum continues to rotate. When it rotates to a certain angle, the two mutually meshing outer cylinders squeeze and crush the slag, and the slag falls into the heat exchanger to realize waste heat recovery.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A blast furnace slag drum rapid cooling dry process device for waste heat recovery, characterized by comprising a blast furnace slag trough mounted on a bracket, a plurality of cooling granulation drums and a heat exchanger;

[0007] The high-temperature slag flows downward through the adjustable-width slot at the bottom of the blast furnace slag trough and adheres to the outer wall of the cooling and granulating drum. The high-temperature slag is cooled into glassy slag, which is then squeezed and crushed in sequence by several groups of vertically arranged cooling and granulating drums. Finally, the glassy slag enters the heat exchanger for waste heat recovery.

[0008] The cooling and granulating drums are arranged in pairs, and each cooling and granulating drum comprises an outer drum, an inner drum and a cooling coil. The closed space formed between the outer drum and the inner drum is filled with a heat-conducting medium, and the cooling coil is buried in the heat-conducting medium.

[0009] To optimize the above technical solutions, specific measures taken also include:

[0010] Furthermore, the inner layer of the blast furnace slag trough is a heat-insulating coating, the middle layer is a high-temperature resistant material, and the outer layer is subjected to heat preservation treatment.

[0011] Furthermore, the surface of the outer cylinder is processed with crushing gear teeth, and the two outer cylinders in the same group are meshed with each other.

[0012] Furthermore, a main shaft is axially passed through the inner drum, and the main shaft is driven by a driving motor, thereby driving the rotation of the entire cooling and granulating drum.

[0013] Furthermore, coolant flows in the cooling coil, and the coolant flows into the cooling coil through the coolant inlet pipe, the inlet main pipe and the inlet branch pipe in sequence, and the coolant in the cooling coil flows out through the outflow branch pipe and the coolant outflow pipe in sequence; the inflow main pipe is fixedly sleeved on the part of the main shaft extending outside the inner cylinder, and the coolant inflow pipe is connected to the inflow main pipe through the inflow rotary joint; the main shaft part is hollow, and the outflow branch pipe is connected to the coolant outflow pipe through the hollow part of the main shaft and the outflow rotary joint; wherein, the coolant inflow pipe, the inflow rotary joint and the coolant outflow pipe do not rotate with the main shaft.

[0014] Furthermore, an expansion cavity is provided on one side of the cooling granulation drum, and the two expansion cavities in the same group are staggered. The expansion cavity is communicated with the closed space between the outer cylinder and the inner cylinder and is used to accommodate the expanded volume of the heat-conducting medium.

[0015] Furthermore, the heat conducting medium is tin or graphite mixed with ceramic glue.

[0016] Furthermore, the heat exchanger is placed directly below the cooling and granulating drum, and the slag crushed by the cooling and granulating drum enters the heat exchanger through a collecting port. The heat exchanger is provided with an oscillation mechanism.

[0017] The beneficial effects of the present invention are as follows: when the device is working, the slag vitrification and slag granulation collection processes are carried out simultaneously to realize continuous production; the coolant and slag are completely separated, and the cooling pipe is not in direct contact with the slag, thereby avoiding coolant leakage caused by damage to the cooling pipe due to thermal fatigue, and essentially eliminating the risk of contact between the coolant and slag; the slag can be efficiently recovered, effectively reducing the serious waste of high-quality waste heat resources of liquid slag, and the heat energy recovery efficiency reaches 70%, which is of great significance to the waste heat recovery and efficient utilization of high-temperature slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] FIG1 is a schematic structural diagram of a blast furnace slag drum rapid cooling dry treatment device according to the present invention.

[0019] FIG2 a is a schematic structural diagram of a blast furnace slag trough according to the present invention.

[0020] FIG2 b is a schematic structural diagram of the notch at the bottom of the blast furnace slag trough of the present invention.

[0021] FIG3 is a schematic structural diagram of the cooling and granulating drum of the present invention.

[0022] FIG4 a is a cross-sectional view of the flow channel of the cooling coil in the cooling granulation drum of the present invention.

[0023] FIG4 b is a schematic diagram of the flow path of the cooling coil in the cooling granulation drum of the present invention.

[0024] FIG5 is a schematic diagram of the working process of granulating and crushing slag according to the present invention.

[0025] The figures are marked as follows: 1-blast furnace slag trough; 1.1-notch; 2-bracket; 3-drive motor; 4-cooling granulation drum; 4.1-cooling liquid outflow pipe; 4.2 outflow rotary joint; 4.3 inflow rotary joint; 4.4 coolant inflow pipe; 4.5 inflow main pipe; 4.6-cooling coil; 4.7-outflow branch pipe; 4.8-inflow branch pipe; 4.9-outer cylinder; 4.10-heat transfer medium; 4.11-expansion chamber; 4.12-inner cylinder; 4.13-main shaft; 5-heat exchanger. DETAILED DESCRIPTION

[0026] The present invention will now be described in further detail with reference to the accompanying drawings.

[0027] The blast furnace slag drum rapid cooling dry process device shown in Figure 1 comprises a blast furnace slag trough 1, a support 2, a drive motor 3, a cooling and granulating drum 4, and a heat exchanger 5. The blast furnace slag trough 1 is located at the bottom of the high-temperature molten slag pool. The cooling and granulating drum 4 is used to rapidly cool, vitrify, and pulverize the liquid slag flowing from the blast furnace slag trough 1. During operation, after the high-temperature liquid slag flows down through the blast furnace slag trough 1 at the bottom of the slag pool, it adheres to the surface of the cooling and granulating drum 4. Cooling coils 4.6 are arranged within the cooling and granulating drum 4. Coolant continuously flows through the cooling coils 4.6. The slag rapidly cools under the influence of the coolant in the coils, forming a glassy state that adheres to the surface of the cooling and granulating drum 4. The cooling and granulating drum 4 is driven by the drive motor 3, which utilizes a reduction motor whose speed is adjustable according to the slag flow rate and temperature. The reduction motor is secured to the machine base via machine feet. Under the control of the drive motor 3, the cooling and granulating drum 4 continues to rotate. When it rotates to a certain angle, the glassy slag attached to the surface of the cooling and granulating drum 4 is squeezed and crushed by the mutually meshing surfaces of the cooling and granulating drum 4 to form powder, which then falls into the heat exchanger 5.

[0028] The structure of the blast furnace slag trough 1 is shown in Figures 2a and 2b. The trough 1 has an inner layer of thermal insulation coating, a middle layer of high-temperature resistant material, and an outer layer of heat-insulating treatment. The bottom of the blast furnace slag trough 1 is provided with an adjustable width slot 1.1. This opening can be adjusted to control the flow of high-temperature molten slag, ensuring that the high-temperature slag forms a uniform film on the surface of the cooling granulation drum 4.

[0029] The structure of the cooling and granulating drum 4 is shown in Figure 3. Cooling coils 4.6 are arranged inside the cooling and granulating drum 4, spirally arranged between the outer drum 4.9 and the inner drum 4.12. A heat-conducting medium 4.10 fills the space between the outer drum 4.9 and the inner drum 4.12, and the cooling coils 4.6 are embedded in the heat-conducting medium 4.10. A main shaft 4.13 axially extends through the inner drum 4.12. This main shaft 4.13 is driven by the drive motor 3, thereby driving the entire cooling and granulating drum 4. Coolant continuously flows through the cooling coils 4.6, passing through the coolant inlet pipe 4.4, the main inlet pipe 4.5, and the inlet branch pipe 4.8. The coolant in the cooling coils 4.6 then flows out through the outlet branch pipe 4.7 and the coolant outlet pipe 4.1. The flow path of the coolant within the pipe is shown in Figures 4a and 4b.

[0030] Specifically, the inflow manifold 4.5 is fixedly mounted on the portion of the main shaft 4.13 that extends beyond the inner cylinder 4.12. The coolant inflow pipe 4.4 is connected to the inflow manifold 4.5 via the inflow rotary joint 4.3. A hole is opened at one end of the main shaft 4.13, creating a hollow portion that serves as a coolant flow path. The outflow branch pipe 4.7 connects to the hollow portion of the main shaft 4.13 and is connected to the coolant outflow pipe 4.1 at the orifice via the outflow rotary joint 4.2. When the main shaft 4.13 rotates, the coolant inflow pipe 4.4, the inflow rotary joint 4.3, and the coolant outflow pipe 4.1 do not rotate with it.

[0031] The heat conducting medium 4.10 must be a thermally conductive material with excellent heat transfer properties. Examples include tin or graphite mixed with ceramic glue. Tin has a melting point of 231.89°C. The operating temperature of the cooling and granulating drum 4 is approximately 600°C, so tin undergoes a phase change from solid to liquid. However, tin's boiling point is 2260°C, far above the operating temperature, making it very stable and unlikely to boil over and pose a risk. Therefore, when the heat conducting medium 4.10 is a metal such as tin, the phase change causes volume changes during operation. Therefore, an expansion chamber 4.11 is required on one side of the cooling and granulating drum 4 to prevent damage to the drum caused by the volume expansion caused by the phase change of the heat conducting material.

[0032] The operating principle of the cooling and granulation drum 4 is as follows: coolant continuously flows from the coolant inlet pipe 4.4 into the cooling coil 4.6 and out of the coolant outlet pipe 4.1. When the high-temperature slag flows to the surface of the outer drum 4.9, it exchanges heat with the coolant in the cooling coil 4.6 through the heat transfer medium 4.10, rapidly cooling the slag to form a glassy state. The heated coolant then flows out of the coolant outlet pipe 4.1. The cooling and granulation drum 4 rotates under the control of the drive motor 3. The drum speed is adjustable according to the amount of slag and the cooling rate. When the cooling and granulation drum 4 rotates to a certain angle, the high-temperature slag cools to form a glassy state. The glassy slag adheres to the surface of the outer drum 4.9 and continues to rotate until the two outer drums 4.9 mesh, where it is then crushed and granulated.

[0033] An implementation case of the present invention is shown in Figure 5. The blast furnace slag trough 1 is connected to the slag pool, and the high-temperature slag flows along the blast furnace slag trough 1. A notch 1.1 is provided at the bottom of the blast furnace slag trough 1. The width of the notch 1.1 can be adjusted according to the production speed to control the slag flow rate. Several groups of cooling granulation rollers 4 are arranged at the lower part of the slag trough. Two cooling granulation rollers 4 form a group, and N groups can be set according to demand. After the high-temperature slag contacts the first group of cooling granulation rollers 4, it is rapidly cooled to form a glassy state, and then passes through N groups of cooling granulation rollers 4 in turn for crushing. The uniform powder formed after crushing falls into the heat exchanger 5 to complete the waste heat recovery.

[0034] The specific operation process of the blast furnace slag drum rapid cooling dry treatment device is as follows:

[0035] Liquid high-temperature slag enters the blast furnace slag trough 1 at the bottom of the slag pool, flows down through the notch 1.1 at the bottom of the blast furnace slag trough 1 to the surface of the cooling and granulation drum 4, and the coolant flows in the enclosed cooling coil 4.6. The cooling coil 4.6 is buried in the heat transfer medium 4.10 between the inner and outer drums. The heat exchange between the heat transfer medium 4.10 and the slag on the surface of the outer drum 4.9 achieves complete separation of the coolant and slag. The cooling coil 4.6 does not directly contact the slag, and the slag adheres to the surface of the outer drum 4.9. The heat is transferred from the heat transfer medium 4.10 between the inner and outer drums to the cooling coil 4.6 buried therein, and is carried away by the coolant in the cooling coil 4.6. The slag is rapidly cooled to about 600°C and forms a glassy state. The glassy slag adheres to the surface of the cooling and granulating drum 4 and continues to rotate. When it reaches the meshing point between the two outer drums 4.9, it is granulated into powder by the crushing teeth machined onto the outer drum 4.9. The granulated slag then enters the heat exchanger 5 for waste heat recovery. The heat exchanger 5 is equipped with an oscillation mechanism to prevent powder from clogging the channels. During operation, the device can simultaneously granulate the slag and recover waste heat, ensuring continuous operation.

[0036] It should be noted that the terms such as "upper", "lower", "left", "right", "front", "back", etc. cited in the invention are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0037] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A blast furnace slag drum rapid cooling dry treatment device for waste heat recovery, characterized in that: The invention comprises a blast furnace slag trough (1) mounted on a support (2), a plurality of cooling and granulating rollers (4) and a heat exchanger (5); The high-temperature slag flows downward through the adjustable-width slot (1.1) provided at the bottom of the blast furnace slag trough (1) and adheres to the outer wall of the cooling and granulating drum (4). The high-temperature slag is cooled into glassy slag. The glassy slag is sequentially squeezed and crushed by a plurality of groups of cooling and granulating drums (4) arranged in a vertical direction and finally enters the heat exchanger (5) for waste heat recovery. The cooling and granulating drums (4) are arranged in pairs, and each cooling and granulating drum (4) comprises an outer drum (4.9), an inner drum (4.12), and a cooling coil (4.6). A heat-conducting medium (4.10) is filled in the closed space formed between the outer drum (4.9) and the inner drum (4.12), and the cooling coil (4.6) is buried in the heat-conducting medium (4.10).

2. The blast furnace slag drum rapid cooling dry treatment device for waste heat recovery according to claim 1, characterized in that: The inner layer of the blast furnace slag trough (1) is a heat-insulating coating, the middle layer is a high-temperature resistant material, and the outer layer is subjected to heat preservation treatment.

3. The blast furnace slag drum rapid cooling dry treatment device for waste heat recovery according to claim 1, characterized in that: The surface of the outer cylinder (4.9) is processed with crushing gear teeth, and two outer cylinders (4.9) in the same group are meshed with each other.

4. The blast furnace slag drum rapid cooling dry treatment device for waste heat recovery according to claim 1, characterized in that: A main shaft (4.13) axially passes through the inner cylinder (4.12), and the main shaft (4.13) is driven by a driving motor (3), thereby driving the rotation of the entire cooling and granulating drum (4).

5. The blast furnace slag drum rapid cooling dry treatment device for waste heat recovery according to claim 4, characterized in that: The cooling liquid flows in the cooling coil (4.6), and the cooling liquid flows into the cooling coil (4.6) in sequence through the cooling liquid inflow pipe (4.4), the inflow main pipe (4.5) and the inflow branch pipe (4.8). The cooling liquid in the cooling coil (4.6) flows out in sequence through the outflow branch pipe (4.7) and the cooling liquid outflow pipe (4.1); the inflow main pipe (4.5) is fixedly sleeved on the part of the main shaft (4.13) extending outside the inner cylinder (4.12). The liquid inlet pipe (4.4) is connected to the inlet main pipe (4.5) through the inlet rotary joint (4.3); the main shaft (4.13) is partially hollow, and the outflow branch pipe (4.7) is connected to the coolant outflow pipe (4.1) through the hollow part of the main shaft (4.13) and the outflow rotary joint (4.2); wherein the coolant inlet pipe (4.4), the inflow rotary joint (4.3) and the coolant outflow pipe (4.1) do not rotate with the main shaft (4.13).

6. The blast furnace slag drum rapid cooling dry treatment device for waste heat recovery according to claim 1, characterized in that: An expansion cavity (4.11) is provided on one side of the cooling and granulating drum (4), and two expansion cavities (4.11) in the same group are staggered. The expansion cavity (4.11) is communicated with the closed space between the outer cylinder (4.9) and the inner cylinder (4.12) and is used to accommodate the expanded volume of the heat-conducting medium (4.10).

7. The blast furnace slag drum rapid cooling dry treatment device for waste heat recovery according to claim 1, characterized in that: The heat conducting medium (4.10) is tin or graphite mixed with ceramic glue.

8. The blast furnace slag drum rapid cooling dry treatment device for waste heat recovery according to claim 1, characterized in that: The heat exchanger (5) is placed directly below the cooling granulation drum (4), and the slag crushed by the cooling granulation drum (4) enters the heat exchanger (5) through a collecting port. The heat exchanger (5) is provided with an oscillation mechanism.

Images