Electric heating device for preheating steel ladle

Abstract

The utility model discloses an electric heating device for preheating a steel ladle, which is an integral device, W-shaped electric heating tubes are arranged in the device, correspond to an upper heating area, a lower heating area and a bottom heating area of the steel ladle respectively and are arranged outside a main body frame of an electric heater respectively, and aluminum silicate heat insulation cotton is filled between the electric heater and the main body frame. The electric heater performs wiring through an internal low-temperature wiring area and is led out to an external junction box through a lead-out wire pile head, the external junction box is provided with a cooling fan, and six furnace chamber temperature measurement double-branch K-scale division thermocouples are arranged in the electric heater and respectively correspond to two upper heating areas, two lower heating areas and two bottom heating areas; the electric heater is internally provided with six pipe meter overtemperature protection double-branch K indexing thermocouples which respectively correspond to two upper heating areas, two lower heating areas and two bottom heating areas.

Description

Technical Field

[0001] The utility model relates to a ladle preheating electric heating device. Background Art

[0002] The ladle is an indispensable and important equipment in the steelmaking process. After a batch of steel is smelted in the converter, the molten steel is sent to the argon blowing, refining and continuous casting platform through the ladle to complete the steel casting task in conjunction with continuous casting. During this period, the main functions of the ladle are to hold and transport the molten steel; deoxidize and alloy the molten steel; adjust the temperature of the molten steel, make the composition uniform and the inclusions float; and perform refining and vacuum treatment outside the furnace. At present, the 150t converter of Bayi Steel uses a direct-fired baking device, which is arranged inside the 150t plant. The mixed gas enters the baking device inside the plant through a pipeline. By burning the mixed gas, the ladle is baked and preheated to 800-900℃. This heating method causes large heat loss due to direct exhaust of flue gas after combustion, especially in the high temperature stage, where the heat loss caused by flue gas exhaust reaches 80%, resulting in low thermal efficiency of the baking preheating device and increased energy consumption. After burning the mixed gas, a large amount of flue gas will be generated, which will pollute the atmosphere. Currently, there are a large number of gas pipelines arranged in the factory for baking machines. Once a gas pipeline or valve leaks, it is very likely to cause a safety accident, posing a huge safety hazard. Summary of the invention

[0003] Aiming at the defects of low heating efficiency, large pollution and high potential safety hazard of current direct-fired roasters, the utility model aims to provide an electric heating device for preheating a ladle.

[0004] The technical scheme of the utility model is: a ladle preheating electric heating device, which is an integral device, wherein W-shaped electric heating tubes are arranged inside and correspond to the upper heating zone, the lower heating zone and the bottom heating zone of the ladle respectively, and are arranged outside the main frame of the electric heater respectively, and aluminum silicate heat insulation cotton is filled between the electric heater and the main frame, the electric heater is wired through the internal low temperature zone wiring area, and is led out to the external wiring box through the lead-out wire pile head, the external wiring box is provided with a cooling fan, and 6 furnace cavity temperature measuring double-branch K-dividing thermocouples are installed inside the electric heater, which correspond to 2 in the upper heating zone, 2 in the lower heating zone and 2 in the bottom heating zone respectively; 6 tube surface over-temperature protection double-branch K-dividing thermocouples are installed inside the electric heater, which correspond to 2 in the upper heating zone, 2 in the lower heating zone and 2 in the bottom heating zone respectively.

[0005] Compared with the prior art, the utility model has the following advantages: 1. Compared with the traditional ladle preheating, the utility model heats the upper, lower and bottom sections of the ladle at different power levels through the electric heating device with continuously adjustable heating power, and the heating efficiency is significantly improved. 2. By using electricity instead of gas for heating, the emission of atmospheric pollutants caused by the combustion of mixed gas is reduced on the one hand, and the safety hazard of gas leakage is eliminated on the other hand. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a schematic diagram of the main structure of the utility model. Implementation

[0007] A ladle preheating electric heating device, such as Figure 1As shown, the device is an integrated device, in which W-shaped electric heating tubes are arranged inside and correspond to the upper heating zone 13, the lower heating zone 14 and the bottom heating zone 15 of the ladle respectively, and are arranged outside the main frame of the electric heater respectively, and aluminum silicate insulation cotton 19 is filled between the electric heater and the main frame. The aluminum silicate insulation cotton has excellent thermal insulation performance, and its thermal conductivity is lower than that of traditional insulation materials, which can effectively reduce energy loss and improve energy utilization. The electric heater is wired through the internal low temperature zone wiring area 12, and the wiring method adopts a triangle connection method. Finally, it is led out to the external wiring box 9 through the lead-out wire pile 11. The external wiring box has a high protection level and is equipped with a cooling fan 10. The high-voltage power supply 1 enters the transformer 3 through the high-voltage switch cabinet 2, and converts the high-voltage power supply (10kV) into the low-voltage power supply (690V) required by the electric heater and then enters the low-voltage switch cabinet 4 and the electric control cabinet 5. The quick plug interface 7 led out at the external wiring box 9 of the heating device extends to the bottom of the ladle. The power supply is connected to the quick plug interface 7 to complete the power wiring work. After power is turned on, the electric heating tube inside the electric heater heats up and heats the ladle to the temperature required by the process by heat transfer. The electric heater has a fully adjustable power function, and the electric control cabinet 5 has the function of cutting off the system power supply and power control. There are 6 furnace cavity temperature measurement double-branch K-type thermocouples 16 installed inside the electric heater, corresponding to 2 in the upper heating zone, 2 in the lower heating zone, and 2 in the bottom heating zone. The appropriate furnace cavity temperature is selected through PLC and transmitted to the temperature control meter on the electric control cabinet through PLC. The temperature control meter feeds back the result to the thyristor according to the set temperature after PID calculation. The thyristor then adjusts the power output of the electric heater (0-100% power adjustment). While ensuring the temperature adjustment accuracy of the heater, the actual output of the power regulator is controlled to achieve the control of the furnace cavity temperature of the heater. Six over-temperature protection double-branch K-type thermocouples 17 are installed inside the electric heater, corresponding to 2 in the upper heating zone, 2 in the lower heating zone, and 2 in the bottom heating zone. When the temperature measured by any thermocouple in the heating area exceeds the set temperature, the over-temperature protection action will be triggered immediately, and the electric control cabinet 4 will cut off the power supply of the corresponding area: when the temperature drops back to the normal value, the area will automatically resume operation. A hoisting device 8 is provided outside the electric heating device. After the electric heating device is hoisted and raised to a certain height by a factory crane, the electric heating device is vertically placed in the ladle so that the electric heating device just covers the ladle mouth; when the heating is finished, the quick connector socket 7 is disassembled and separated, and the electric heating device is hoisted out by the crane.

[0008] like Figure 1As shown, the device is integrated with a heating power supply, a power control system, and an electric heater body, wherein the heating power supply is a three-phase AC power supply (AC690V) and has a continuously adjustable heating power function. A hoisting device 8 is provided on the upper part of the electric heater body to facilitate the hoisting of the electric heater. The electric heater body is divided into an upper heating zone, a lower heating zone, and a bottom heating zone. The upper, lower, and bottom electric heating tubes are W-type electric heating tubes. The outer shell of the heating tube is made of 2520Si2 material, which has good stability in a high temperature environment and can withstand high temperature corrosion and oxidation. At the same time, it has excellent tensile strength and hardness and can withstand working conditions under high temperature and high pressure. The internal resistance wire is made of Ni80Cr20, which has excellent heat resistance and corrosion resistance. It can work stably for a long time at high temperature. The temperature coefficient of the resistance wire is low. Even if it works at high temperature, its resistance value will not increase excessively, thereby ensuring the stability and accuracy of the electric heating equipment. By filling high-performance insulating materials between the electric heating tube and the resistance wire, it can withstand high temperatures of 800℃~900℃ for a long time. The electric heating tube adopts a special-shaped bending design, which can effectively release the extension and deformation caused by high temperature. The main frame 20 of the electric heater is made of carbon steel-austenitic stainless steel. The electric heater is welded and fixed by an alloy high-temperature resistant clamp 18. Since the internal components of the electric heater work in high-temperature conditions for a long time, all welds must ensure the force requirements in the high-temperature state. Aluminum silicate insulation cotton 19 is filled between the electric heater and the main frame. Aluminum silicate insulation cotton has excellent thermal insulation performance and its thermal conductivity is lower than that of traditional insulation materials. It can effectively reduce energy loss and improve energy utilization. The electric heater is connected through the internal low-temperature zone wiring area 12. The wiring method adopts a triangle connection method, and finally leads to the external wiring box 9 through the lead-out wire pile head 11. The external wiring box has a high protection level and is provided with a cooling fan 10, which can dissipate the heat of the low-temperature wiring area inside the furnace cavity in time to ensure the service life of the internal cable. The electric control cabinet 5 has conventional electrical protection, such as short circuit protection, over-temperature protection, overload protection, three-phase unbalanced protection, thyristor overheating protection, etc. A furnace cavity temperature measuring double-branch K-division thermocouple 16 is installed inside the electric heater, which can set the furnace cavity temperature and achieve 0%-100% adjustment of the electric heater output power through the temperature control meter and PLC. At the same time, a tube meter over-temperature protection double-branch K-division thermocouple 17 is installed inside the electric heater. When the temperature measured by any thermocouple in the area exceeds the set temperature, the over-temperature protection action will be triggered immediately, and the electric control cabinet will cut off the power supply of the corresponding area: when the temperature drops back to the normal value, the area will automatically resume operation.

[0009] The utility model preheats the ladle through an electric heating device, replacing coal gas with electricity, which improves the heating efficiency of the ladle preheating on the one hand, reduces carbon dioxide emissions on the other hand, and greatly improves the safety and stability of the heating process. If green electricity is used for heating, zero carbon dioxide emissions will be achieved during the heating process.

Claims

1. A ladle preheating electric heating device, which is an integrated device, characterized in that: W-shaped electric heating tubes are arranged inside and correspond to the upper heating zone, lower heating zone and bottom heating zone of the ladle respectively, and are arranged outside the main frame of the electric heater respectively. Aluminum silicate insulation cotton is filled between the electric heater and the main frame. The electric heater is wired through the internal low-temperature zone wiring area and led out to the external wiring box through the lead-out wire pile. The external wiring box is provided with a cooling fan. Six furnace cavity temperature measurement double-branch K-dividing thermocouples are installed inside the electric heater, corresponding to two in the upper heating zone, two in the lower heating zone, and two in the bottom heating zone respectively; six tube surface over-temperature protection double-branch K-dividing thermocouples are installed inside the electric heater, corresponding to two in the upper heating zone, two in the lower heating zone, and two in the bottom heating zone respectively.

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