System for preheating and melting solid materials and steel preheating and melting method

Abstract

The invention discloses a system for preheating and melting a solid material and a steel preheating and melting method, which adopt the design of an inclined blanking and preheating channel associated with the characteristics of scrap steel, can effectively consider the rapidity, stability and accuracy of scrap steel blanking, can also effectively increase the heat exchange area between the scrap steel and high-temperature flue gas, and improves the heat exchange efficiency of the scrap steel and the high-temperature flue gas. The heat exchange efficiency is effectively improved, the production efficiency is greatly improved, and the energy consumption is reduced. And the real-time preheating temperature of the scrap steel in the heat exchange process is detected, regulated and controlled, so that the preheating temperature of the scrap steel and the utilization efficiency of flue gas waste heat are effectively improved. In addition, during melting of the waste steel, a gas type heating burner and an electromagnetic heater are combined and matched, rapid heating and rapid melting of the solid waste steel are jointly achieved, the overall production efficiency is further improved, and energy consumption is further reduced. The system is simple in structure, easy to operate and control, simple and convenient in preheating and founding process, high in production efficiency and low in energy consumption, and has excellent prospects of large-scale popularization and application.

Description

Technical Field

[0001] The present invention relates to preheating and melting of solid materials, in particular to a system for preheating and melting solid materials and a preheating and melting steel method, belonging to the technical field of steel smelting. Background Art

[0002] In the steel production sector, steel companies face the dual pressures of energy conservation, emission reduction, and cost reduction. The traditional converter (BOF) process, which uses molten iron produced from ore and coal coke, offers a short smelting cycle, high production efficiency, and low cost per ton of steel. However, its production involves sintering and pelletizing processes, as well as blast furnace operations, resulting in high carbon emissions and severe environmental pollution. The electric furnace (EAF) process, on the other hand, uses recycled scrap steel as raw material, resulting in lower carbon emissions and less environmental pollution. However, it suffers from a long smelting cycle, low production efficiency, and high cost per ton of steel.

[0003] Scrap steel is a clean resource that can be recycled indefinitely, and increasing its utilization rate has become an important development direction for the steel industry. For long processes, increasing the scrap steel ratio can reduce carbon emissions, improve resource utilization efficiency, and lower production costs. For short processes, increasing the scrap steel ratio or even smelting all scrap steel is in line with the dual carbon policy. Moreover, if the scrap steel preheating effect can be improved, production costs can be significantly reduced and its competitiveness can be improved. Therefore, the development of an efficient scrap steel preheating system for steel melting furnaces and its control method are of great practical significance for increasing the proportion of scrap steel in the steelmaking process and achieving green and efficient development of the steel industry.

[0004] However, existing scrap preheating technologies have the following problems: 1) Low preheating efficiency and limited equipment and space: In the electric furnace short-process process, the technology of preheating scrap steel with high-temperature process flue gas alone is insufficient. For example, in the horizontal Considy equipment, the scrap steel and the flue gas flow in the opposite direction and mainly rely on radiation heat exchange, which has low heat exchange efficiency and the scrap steel preheating temperature is often below 500°C. Although the vertical shaft preheating method can achieve convection heat exchange, the finger adhesion problem at the bottom of the shaft seriously hinders the normal operation of the equipment, and the equipment and space are greatly limited. 2) The preheating capacity of the scrap steel is limited and the surface oxidation is severe: The scrap steel is preheated by burning with a burner, and the scrap steel is loaded into the ladle. The ladle is preheated by burning natural gas or other media. This method limits the amount of scrap steel added to the ladle, and the hot flue gas cannot easily reach the scrap steel at the bottom of the ladle, resulting in poor preheating effect. After the flame hits the scrap steel surface, it easily rebounds to the outside of the ladle, resulting in energy waste and severe oxidation of the surface scrap steel. While using a separate heating furnace to heat scrap allows for flexible control of the amount of preheated scrap, it also presents issues such as slow heating rates, low preheating temperatures, limited surface heating, and difficulty in accurately and stably feeding. 3) The preheating temperature is low and difficult to raise further: When adding scrap to a converter or ladle, the scrap temperature after preheating is relatively low compared to the molten iron or steel. Melting the scrap requires additional heat, but the converter or ladle has limited heat capacity. If the scrap ratio is too high, the added scrap will not be fully melted, impacting smooth production. Currently, no suitable preheating device is available that can further increase the preheating temperature of the scrap or even directly melt the scrap. 4) Heating rate and cost: Using burners to preheat scrap allows for faster heating and lower costs before the preheating temperature reaches 1000°C. However, if the preheating temperature exceeds 1000°C, gas consumption increases significantly, the temperature rises slowly, and the high-temperature flue gas cannot be effectively utilized, resulting in low energy efficiency and high costs. When using electromagnetic induction heating to preheat scrap, the temperature rises slowly when the scrap temperature is low (below 800°C), affecting preheating efficiency. Currently, there is no fast, efficient, and low-cost method for preheating scrap at high temperatures. Summary of the Invention

[0005] To address the problems of poor scrap preheating in existing technologies, resulting in low production efficiency and high energy consumption, the present invention provides a system and method for preheating and melting solid materials. This system utilizes an inclined material discharge and preheating channel design, effectively balancing the rapidity, stability, and accuracy of scrap discharge. It also effectively increases the heat exchange area between the scrap and the high-temperature flue gas, effectively improving heat exchange efficiency, significantly increasing production efficiency, and reducing energy consumption. Furthermore, a combination of gas-fired heating burners and electromagnetic heaters is used during scrap melting to rapidly heat and melt the solid scrap, further improving overall production efficiency and reducing energy consumption.

[0006] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0007] According to a first embodiment of the present invention, a system for preheating and melting solid materials is provided:

[0008] A system for preheating and melting solid materials includes an inclined feeding and preheating channel and a melting furnace. The bottom outlet of the inclined feeding and preheating channel communicates with the upper portion of the melting furnace chamber. A breathable material retaining mechanism is provided at the bottom of the inclined feeding and preheating channel. A melt outlet is provided at the bottom of the melting furnace. A heating device is also provided within the melting furnace. Preferably, the inclination angle of the inclined blanking and preheating channel is less than 90°, preferably 5°~85°, more preferably 10°~80°, for example, 1°, 2°, 3°, 4°, 5°, 6°, 8°, 10°, 12°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 86°, 87°, 88°, 89° or a range value with any two of them as endpoints (such as 30~60°, 30~65°, etc.).

[0009] Preferably, a material partition is provided within the inclined material discharge and preheating channel to separate the interior of the inclined material discharge and preheating channel into an upper temporary storage chamber and a lower preheating chamber. A smoke exhaust port is provided in the upper wall of the lower preheating chamber. A breathable material retaining mechanism is provided at the bottom of the lower preheating chamber.

[0010] Preferably, a temperature monitoring device and / or a pressure control device is provided at the smoke exhaust port. Preferably, the temperature monitoring device is a thermocouple. The pressure control device is composed of a pressure sensor and a speed-regulating fan.

[0011] Preferably, the top end of the separator plate extends through the top wall of the inclined material unloading and preheating channel and then to the outside of the inclined material unloading and preheating channel. A separator drive motor connected to the top end of the separator plate is provided on the top wall surface of the inclined material unloading and preheating channel. The separator drive motor drives the separator plate to rise and fall in a direction perpendicular to the axis of the inclined material unloading and preheating channel, thereby achieving connection or isolation between the upper temporary storage chamber and the lower preheating chamber.

[0012] Preferably, the breathable material blocking mechanism is a material blocking claw. A material blocking drive motor connected to the breathable material blocking mechanism is also provided at the bottom end of the lower preheating chamber. The material blocking drive motor drives the breathable material blocking mechanism to swing up and down in an arc-shaped manner, thereby enabling the breathable material blocking mechanism to block and open the inclined material discharge and the bottom outlet of the preheating channel. Preferably, the breathable material blocking mechanism has 2 to 30 claws, preferably 3 to 20. The width of a single claw is 2 to 20 cm, preferably 3 to 10 cm. The spacing between two adjacent claws is 1 to 15 cm, preferably 2 to 8 cm.

[0013] Preferably, a cooling medium channel and a cooling medium inlet and a cooling medium outlet connected to the cooling medium channel are further provided inside the air-permeable material blocking mechanism.

[0014] Preferably, the heating device includes a heating burner and an electromagnetic heater. The heating burner is disposed in the upper portion of the inner cavity of the melting furnace. The electromagnetic heater is disposed in the lower portion of the inner cavity of the melting furnace. Preferably, both the heating burner and the electromagnetic heater are disposed on a side away from the melt outlet. Preferably, the feed end of the melt outlet is an overflow design that is higher than the bottom wall of the melting furnace inner cavity (for example, the end of the bottom wall of the melting furnace inner cavity near the melt outlet is a stepped design, with the melt outlet located on the highest step).

[0015] Preferably, the system further comprises a lifting angle adjustment mechanism. The lifting angle adjustment mechanism comprises a hydraulic cylinder and a lifting support rod. The hydraulic cylinder is arranged on the ground below the inclined blanking and preheating channel, the bottom end of the lifting support rod is connected to the piston rod of the hydraulic cylinder, and the top end of the lifting support rod is connected to the upper bottom wall of the inclined blanking and preheating channel. The bottom end of the inclined blanking and preheating channel is hinged to the furnace wall of the melting furnace. The hydraulic cylinder drives the inclined blanking and preheating channel to rotate in the vertical direction with its bottom end as the rotation center through the lifting and lowering of the lifting support rod, thereby realizing the adjustment of the inclination angle of the inclined blanking and preheating channel.

[0016] Preferably, the system further comprises a thermal imager, which is arranged on the top wall of the inner cavity of the melting furnace.

[0017] Preferably, the system also includes a control device, which is respectively associated with the temperature monitoring device, pressure control device, material isolation drive motor, material blocking drive motor, heating device, lifting angle adjustment mechanism, and thermal imager to coordinate and regulate their working states.

[0018] According to a second embodiment of the present invention, a method for preheating molten steel is provided:

[0019] A method for preheating molten steel or a method for preheating molten steel using the system according to the first embodiment, the method comprising the following steps:

[0020] S1. First, determine the inclination angle of the inclined feeding and preheating channel according to the basic properties of the current steel. Then, the steel is directly fed into the melting furnace through the inclined feeding and preheating channel for melting.

[0021] S2. During the smelting process, steel is added to the inclined feeding and preheating channel and the added steel is temporarily retained in the inclined feeding and preheating channel through a breathable material blocking mechanism.

[0022] S3. The hot flue gas in the melting furnace is transported to the inclined unloading and preheating channel to preheat the retained steel.

[0023] S4: When the steel in the melting furnace is smelted, the molten steel is discharged through the melt outlet, and the steel preheated in the inclined feeder and preheating channel is added to the melting furnace to continue smelting. Steps S2 to S4 are repeated in this cycle.

[0024] Preferably, in step S1, determining the inclined angle of the inclined blanking and preheating channel according to the basic properties of the current steel material includes:

[0025] S101. Establish an equation for calculating the sliding speed of the steel at different inclination angles based on the average size of the current steel. The equation is as follows:

[0026] (I).

[0027] In formula (I), v s is the sliding speed of the steel, m / s. Different inclination angles of inclined unloading and preheating channels, rad. is the friction coefficient when the steel slides down, and the value is 0.2~0.6. g is the acceleration due to gravity, and the value is 9.8m / s 2 k1 is the steel material size influence coefficient, ranging from 0.1 to 5.0. l0 is the average length of the steel material, in meters. w0 is the average width of the steel material, in meters. h0 is the average thickness of the steel material, in meters. The sliding speed of the steel material at different inclination angles is calculated using formula (I).

[0028] S102. According to the mass and average size of the steel material, a calculation equation for the impact force on the air-permeable material retaining mechanism (101) at different sliding speeds is established. The calculation equation is as follows:

[0029] (II).

[0030] In formula (II), F is the impact force on the air-permeable material blocking mechanism (101) at different sliding speeds, N. m s is the mass of the steel, kg. Δt is the collision time between the steel and the breathable material retaining mechanism (101), s. k2 is the force coefficient of the material retaining mechanism, ranging from 10 to 100. The impact force on the breathable material retaining mechanism (101) at different sliding speeds is calculated according to formula (II).

[0031] S103, using the sliding speed of the steel material at the same inclination angle of the inclined unloading and preheating channel (1) and the impact force on the breathable material blocking mechanism (101) as independent variables to establish a comprehensive evaluation factor estimation model, the estimation model is as follows:

[0032] (III).

[0033] In formula (III), E is a comprehensive evaluation factor. The maximum sliding speed of steel allowed by the working conditions, m / s. The maximum bearing capacity of the breathable material retaining mechanism (101) allowed by the working conditions, N. , It is the optimal comprehensive parameter of steel size under ideal production conditions, and its value ranges from 5 to 50. is the factor weight of steel decline rate, is the weight of the force factor of the breathable material retaining mechanism (101), is the weight of the steel size factor, where: w v +w F +w s =1, 、 、 All are greater than 0 and less than 1. According to formula (III), different comprehensive evaluation factor values ​​are calculated, where the value corresponding to the comprehensive evaluation factor reaching the maximum value is The value is the inclination angle of the inclined unloading and preheating channel (1) under the current working condition.

[0034] Preferably, the method further comprises: during the smelting process, calculating the current real-time temperature of the steel material in real time according to the steel material preheating temperature estimation model, and adjusting the negative pressure at the smoke exhaust port (105) of the inclined material discharge and preheating channel (1) according to the change of the current real-time temperature of the steel material to reduce heat loss. Wherein: the steel material preheating temperature estimation model is as follows:

[0035] ……(IV).

[0036] In formula (IV), k3 is the flue gas velocity influence coefficient, which ranges from 0.8 to 2.0. d is the distance between two adjacent retaining claws of the breathable retaining mechanism (101), in cm. out is the negative pressure at the exhaust port (105), Pa. γ is the smoke resistance coefficient. ρ g is the smoke density, g / cm 3 D is the diameter of the smoke outlet (105), cm. p is the specific heat capacity of flue gas, J / (kg·k). t is the duration of the unit time period, ranging from 60 to 600 seconds. in is the initial temperature of the flue gas, °C. out is the flue gas temperature at the exhaust port (105), °C. m s is the mass of steel, kg. C s T is the specific heat capacity of steel, J / (kg·k).s,i is the temperature of scrap steel before the current time period, ℃. is the temperature of scrap steel after the current time period, ℃ (i is an integer greater than or equal to 0, and T s,0 is the measured value, ranging from 10 to 30°C). The real-time preheating temperature of the steel after different time periods is calculated using formula (IV).

[0037] As a preference, the target preheating temperature of the current steel is set as T obj , ℃. Then we have:

[0038] like -T obj >0, indicating that the current preheating temperature of the steel has reached the target value and insulation operation is required.

[0039] like -T obj ≤0, indicating that the current preheating temperature of the steel is lower than the target value and the temperature needs to be raised.

[0040] Preferably, the method further comprises: the heat preservation operation is: adjusting the smoke exhaust port (105) to a slightly negative pressure through the pressure control device (107). The slightly negative pressure is -5 to -20 Pa, preferably -10 to -15 Pa. And / or

[0041] The heating operation is as follows: if the flue gas temperature T at the exhaust port (105) out -T obj ≤50℃, indicating that the exhaust gas temperature is not over-temperature, and the negative pressure at the exhaust port (105) needs to be increased through the pressure control device (107). If the exhaust gas temperature T out -T objj >50°C, indicating that the exhaust gas temperature has exceeded the upper limit, and the negative pressure at the exhaust port (105) needs to be reduced by the pressure control device (107). The negative pressure is -5 to -120 Pa, preferably -10 to -100 Pa.

[0042] In the prior art, traditional preheating devices often employ simple horizontal or vertical structures, resulting in numerous deficiencies in material transport. For example, in horizontal preheating devices, scrap steel is transported by mechanical means, resulting in slow start-up and shutdown response, making it difficult to precisely control the feed rate and time intervals, and often leading to over- or under-feeding. In contrast, the present invention provides a system for preheating and melting solid materials, primarily comprising an inclined feed and preheating channel and a melting furnace, interconnected in series. The inclined feed and preheating channel is used to feed the scrap steel to be melted into the melting furnace. However, prior to addition, the scrap steel is preheated within the channel through countercurrent heat exchange with the high-temperature flue gas from the melting furnace, raising the scrap steel temperature, effectively improving subsequent scrap melting efficiency, and reducing melting energy consumption. It should be noted that this inclined feed and preheating channel, by adjusting the inclination angle, cleverly utilizes gravity as the power source for transporting different types of scrap steel. Under the action of gravity, the system descends at a steady speed, ensuring a precisely controllable amount of scrap steel delivered each time, effectively resolving the difficulty in controlling the material transport rhythm of conventional devices. Compared to the mechanically driven loading method of traditional horizontal preheating devices, the inclined unloading and preheating channels increase loading efficiency by 30-50%, significantly shortening loading time and improving overall production efficiency. Furthermore, when the inclined unloading and preheating channels utilize high-temperature flue gas to preheat the scrap, the contact area and contact time with the flue gas are greatly increased, significantly improving the efficiency of flue gas heat utilization and the scrap preheating temperature.

[0043] It should be noted that when scrap steel is loaded and preheated through the inclined unloading and preheating channel, it will continue to slide downward under the action of its own gravity, and the length of the inclined unloading and preheating channel is generally fixed, that is, the time for the scrap steel to slide through the inclined unloading and preheating channel is generally relatively short. During this process, it is difficult to preheat the scrap steel to the target temperature. At the same time, it takes a certain amount of time for the scrap steel in the melting furnace to melt into the liquid phase. Therefore, it is impossible to continuously add scrap steel through the inclined unloading and preheating channel indefinitely. Therefore, an intermittent addition method is generally adopted, that is, a breathable material blocking mechanism is provided at the bottom end of the inclined unloading and preheating channel to retain the scrap steel in the inclined unloading and preheating channel for a certain period of time. After the scrap steel is preheated to the target temperature, the breathable material blocking mechanism slides the preheated scrap steel into the melting furnace. At this time, the scrap steel of the previous batch in the melting furnace is basically melted into the liquid phase and discharged. The breathable material blocking mechanism is a structure that can prevent the scrap steel from sliding down but does not isolate the flow of smoke. Preferably, the pneumatic material blocking mechanism is designed as a material blocking claw.

[0044] Furthermore, in the present invention, the inclined unloading and preheating channels are usually made of high-temperature resistant and wear-resistant alloy materials, which can withstand the erosion of high-temperature flue gas and the friction when the scrap steel slides. The inclined unloading and preheating channels serve as the main channels for the scrap steel to slide and exchange heat with the high-temperature flue gas. The use of gravity allows the scrap steel to slide down naturally, reducing additional power consumption and greatly improving the feeding efficiency. At the same time, the inclined design increases the contact time and area between the scrap steel and the high-temperature flue gas, which is beneficial to improving the heat exchange efficiency. In addition, in order to better realize the waste heat of the scrap steel, the inclination angle of the inclined unloading and preheating channels is It is not fixed, but closely related to the characteristics of the scrap steel to be processed, that is, for different scrap steels, the inclination angles of the inclined unloading and preheating channels will also change accordingly. In the scrap preheating system of the steel melting furnace, determining the optimal inclination angle α is crucial to improving the scrap preheating effect. Different types of scrap steel differ in size, density, porosity, etc. These factors will affect the sliding characteristics of the scrap steel, the force on the baffle claws, and the permeability and heat exchange efficiency of the flue gas. Therefore, in determining the optimal inclination angle α, it is necessary to comprehensively consider factors such as the scrap steel sliding speed and the force on the baffle claws of the breathable baffle mechanism: Assuming that the average length of the scrap steel is l0 (unit: m), the average width is w0 (unit: m), and the average thickness is h0 (unit: m), the motion equations for the sliding speed v (unit: m / s) of scrap steel of different sizes are as follows:

[0045] (I).

[0046] In formula (I), g is the acceleration due to gravity, which is generally taken as 9.8m / s 2 . is the friction coefficient between the steel and the trough, and its value is 0.2~0.6. is the steel size influence coefficient, ranging from 0.1 to 5.0. In other words, according to formula (I), the sliding speed of scrap steel at different inclination angles can be calculated.

[0047] When the scrap steel's sliding speed v is known, the impact force F (unit: N) on the stop claw when the scrap steel contacts it can be calculated using the following formula:

[0048] (II).

[0049] In formula (II), m s is the mass of the steel, kg (generally, the mass of the steel can be obtained by weighing directly or by calculation: , is the density of steel, kg / m 3Δt is the collision time between the steel and the breathable material stopper (an empirical estimate, generally ranging from 0.01 to 1 second). k2 is the force coefficient of the material stopper, ranging from 10 to 100. In other words, using Formula (II), we can calculate the impact force on the material stopper claw of the breathable material stopper at different sliding speeds.

[0050] To determine the optimal tilt angle , introduce the comprehensive evaluation factor E:

[0051] (III).

[0052] In formula (III), The maximum sliding speed of steel allowed by the working conditions, m / s. The maximum bearing capacity of the breathable material retaining mechanism (101) allowed by the working conditions, N. , It is the optimal comprehensive parameter of steel size under ideal production conditions, and its value ranges from 5 to 50. is the factor weight of steel decline rate, is the weight of the force factor of the breathable material retaining mechanism (101), is the weight of the steel size factor, where: w v +w F +w s =1, 、 、 are all greater than 0 and less than 1. That is, according to formula (III), different tilt angles are calculated The corresponding comprehensive evaluation factor value. The value is the inclination angle of the inclined material feeding and preheating channel under the current working condition. The steps to obtain the maximum value of the comprehensive evaluation factor are as follows: Set the inclination angle adjustment range of the inclined material feeding and preheating channel to 30~60°, then first give an initial inclination angle of 30°, then =0.524 (30° converted to radians is constrained to 0.524). Then, according to the above formulas (I) and (II), we can calculate =0.524 corresponding to v s1 and F1, and then calculate the corresponding E1 according to formula (III). Finally, increase the tilt angle by a certain step size (such as 0.01 radians) to obtain , and then calculate according to formulas (I), (II), and (III) respectively =0.524+0.01 corresponding to v s2, F2 and E2; repeat the above process until all the comprehensive evaluation factor E values ​​corresponding to the entire tilt angle range of 30~60° (0.524~1.047 radians) are traversed, and then compare all the calculated E values ​​to find the tilt angle that makes E reach the maximum value ,this That is, the inclination angle of the inclined feeding and preheating channel corresponding to the current optimal comprehensive conditions of steel.

[0053] Furthermore, in the present invention, after research, it was found that when the breathable material blocking mechanism is designed as a material blocking claw, the specific structural characteristics of the material blocking claw (such as the width b of the material blocking claw, the number of claws n of the material blocking claw, the distance d between two adjacent material blocking claws, etc.) also have a relatively important impact on the scrap preheating effect. In determining the specific structural characteristics of the material blocking claw, it is necessary to comprehensively consider the impact of the material blocking claw on the smoke permeability and material blocking performance: First, the consideration of the width b of the material blocking claw: In order to ensure the strength of the material blocking claw, according to the bending normal stress formula of material mechanics (Where M is the bending moment, W is z is the bending resistance coefficient, which is 1×10 -6 ~5×10 -4 ). For rectangular cross-section retaining claws: ( is the length of the blocking claw, which is the same as the depth of the inclined unloading and preheating channel). Due to the stress on the blocking claw Need to be less than or equal to the allowable stress of the material [ ], and the bending moment M and the maximum force F on the blocking claw max Related (assuming the force acts on the midpoint of the retaining claw, then: ), from which we can get the inequality: , further deducing Second: Consideration of the number n of the blocking claws and the distance d between two adjacent blocking claws: Based on the condition that the width of the blocking claws is the same as the width of the inclined feeding and preheating channel, the relationship can be obtained: (in = is the width of the inclined feeding and preheating channel). Considering the smoke permeability, according to the smoke flow formula , it can be deduced that (in is the flue gas volume (experience value, which can be manually corrected based on feedback changes in working conditions), is the flue gas velocity, In addition, the distance d between two adjacent blocking claws must be smaller than the minimum characteristic size a of the scrap steel to ensure the blocking effect. min (generally the average size of scrap steel), i.e. The ideal n and d values ​​can be obtained by combining the three equations. It should be noted that the specific structural characteristics of the retaining claw are difficult to change in real time during use. This is generally achieved by directly replacing retaining claws of different specifications that meet the corresponding b, n, and d values.

[0054] In the present invention, to adjust the tilt angle of the inclined feeding and preheating channel when preheating and melting steels of different properties, the bottom end of the inclined feeding and preheating channel is hinged to the furnace wall of the melting furnace (e.g., a pin and bearing combination or a hinged device such as that used to bend between excavator booms). Simultaneously, a lifting angle adjustment mechanism is provided at the other end (top or near the top) of the inclined feeding and preheating channel. This mechanism drives the top end of the inclined feeding and preheating channel to rotate vertically about its bottom end, thereby adjusting its tilt angle. It should be noted that the lifting angle adjustment mechanism is a device that provides both support and lifting functions, such as the combination of a hydraulic cylinder and lifting support rods exemplified in the present invention, or it may be other existing, established devices with the same function (e.g., a lifting and tilting device for controlling the tilting of a truck bed).

[0055] In the present invention, a partition plate is provided in the inclined unloading and preheating channel to separate the inner cavity of the inclined unloading and preheating channel into an upper temporary storage chamber and a lower preheating chamber, that is, the inclined unloading and preheating channel as a whole is divided into two main areas, upper and lower. The upper temporary storage chamber is a scrap steel storage area, which is used to temporarily store scrap steel to be preheated. The lower preheating chamber is a scrap steel preheating area, which is a key area for realizing heat exchange between scrap steel and high-temperature flue gas. The two areas are separated by a solid partition plate that can be lifted up and down. The partition plate plays an important role in controlling the conveying rhythm of scrap steel. The partition plate is generally made of high-strength heat-resistant steel plate, and the surface is specially treated (such as applying a wear-resistant layer and a temperature-resistant layer) to enhance its wear resistance and resistance to high-temperature oxidation. The partition plate is mainly used to control the timing and amount of scrap steel entering the scrap steel preheating area. When scrap steel needs to be added to the scrap steel preheating area, the partition plate is lifted and opened, and the scrap steel enters the scrap steel preheating area from the scrap steel storage area under the action of gravity; when the scrap steel preheating area reaches a certain amount of scrap steel storage, the partition plate drops and closes to prevent the scrap steel from continuing to enter, ensuring that the amount of scrap steel in the preheating area remains within an appropriate range, ensuring the preheating effect and the stability of the production rhythm.

[0056] In the present invention, between the scrap steel preheating zone and the steel melting furnace, the breathable material blocking mechanism is preferably designed as a material blocking claw that can be lifted in an arc shape (for example, the top of the material blocking claw is hinged to the inclined material discharge and preheating channel through a bearing and a rotating shaft, and the material blocking claw can swing up and down in an arc shape under the support of the hinge. The material blocking drive motor drives the material blocking claw to rotate and swing upward, which opens the material blocking claw, and the scrap steel can slide downward along the inclined material discharge and preheating channel; the material blocking drive motor drives the material blocking claw to rotate and swing downward, which closes the material blocking claw, and the scrap steel is blocked by the material blocking claw). Each claw of the material blocking claw has a certain distance between them. This design makes the scrap steel load-bearing mainly borne by the inclined material discharge and preheating channel, effectively avoiding the deformation and damage of the material blocking claw due to excessive force, while not affecting the air permeability of the material blocking claw, ensuring that high-temperature flue gas can smoothly enter the scrap steel preheating zone. The claws of the retaining claw are generally made of a high-temperature-resistant, high-strength alloy. On the one hand, they effectively prevent scrap from entering the steelmaking furnace prematurely, ensuring that the scrap is fully preheated in the preheating zone. On the other hand, the appropriate claw spacing ensures that the hot flue gas does not interfere with the smooth passage of hot flue gas into the scrap preheating zone, thus ensuring heat exchange between the scrap and the hot flue gas. In actual operation, the retaining claw's swinging arc-shaped lifting design allows for more flexible opening and closing, reduces the impact force of the scrap on it, and extends its service life. After actual operation, the use of this retaining claw design has been verified to reduce equipment downtime due to retaining issues by over 80%.

[0057] To further enhance the durability of the retaining claw in high-temperature environments, a cooling medium channel, along with a cooling medium inlet and outlet, is provided within the retaining claw. By designing the retaining claw as a water-cooled structure, thermal deformation that could affect its proper operation and service life is avoided. The circulating water keeps the retaining claw within its proper operating temperature range.

[0058] In the present invention, a smoke exhaust port is provided on the upper wall of the lower preheating chamber, from which the smoke that has completed heat exchange with the scrap steel is discharged. In addition, a temperature monitoring device (preferably a thermocouple) and / or a pressure control device (preferably a combination of a pressure sensor and a speed-regulating fan) are also provided at the smoke exhaust port. The temperature monitoring device is used to monitor the temperature of the smoke at the smoke exhaust port in real time, providing accurate data for the control system. By monitoring temperature changes, the operator can promptly adjust the operating parameters of the device, such as adjusting the timing of the action of the material partition plate and the material blocking claw, and optimizing the smoke flow rate according to the temperature conditions, to ensure the stability and efficiency of the scrap steel preheating process. The pressure control device can accurately measure the outlet pressure of the smoke exhaust port. The control device receives the data fed back by the pressure sensor and analyzes and processes it according to the preset pressure value. The speed-regulating fan is installed on the smoke duct of the smoke exhaust port and is connected to the control device. The speed can be adjusted according to the instructions of the control device. In addition, it also includes signal transmission lines and pipelines connecting various devices to ensure smooth data transmission and smoke flow. The pressure control device achieves precise control of the pressure at the outlet of the scrap steel preheating zone by adjusting the speed of the fan, thereby regulating the scrap steel preheating temperature.

[0059] In the present invention, a heating device for heating and melting preheated scrap steel is provided within the melting furnace. The heating device comprises a gas-fired heating burner for rapidly heating the scrap steel and an electromagnetic heater for rapidly melting the scrap steel. The gas-fired heating burner is used to rapidly heat the scrap steel that has entered the melting furnace and is piled above the molten steel. It employs a preheating structure, including a combustion air casing, a gas casing, and the like. A tubular heat exchanger can be provided at the front end of the combustion air, utilizing high-temperature flue gas to preheat the combustion air and conserve energy. A gas-fired heating burner is positioned on either side of the scrap steel landing area within the melting furnace, each burner having a specific horizontal and vertical deflection angle. The electromagnetic heater is used to rapidly melt the scrap steel within the molten steel. It utilizes electromagnetic induction to heat the molten steel, rapidly melting the scrap steel through heat transfer from the molten steel. The alternating magnetic field generated by electromagnetic induction generates an induced current in the molten steel, which in turn generates heat through the resistance of the molten steel, thereby heating the molten steel and the scrap steel. That is to say, under the steel retention operation, the high-temperature scrap steel at the bottom of the melting furnace is quickly melted by the heat conduction of the molten steel and electromagnetic induction heating, while the low-temperature scrap steel above is slowly heated by electromagnetic induction heating. At this time, the burner is turned on to use the heat from natural gas combustion to quickly preheat or even partially melt the scrap steel. The high-temperature flame ejected from the burner directly acts on the scrap steel, providing additional heat for the scrap steel and accelerating its heating process.

[0060] In the present invention, the melting furnace adopts a dump-free tapping method, facilitating continuous production. The molten steel outlet is designed as a step. When the steel is normally retained, the molten steel level is lower than the tapping step. During tapping, a ladle is placed below the molten steel outlet, acetylene is burned through the tapping port, and molten steel flows into the ladle. When the molten steel level falls below the tapping step, tapping is stopped and the molten steel outlet is blocked with drainage sand. The tapping step has a certain height.

[0061] In the present invention, the preheating and melting process of the present invention is roughly as follows: Scrap steel preheating stage: The scrap steel is sucked into the scrap steel storage area (i.e., the upper temporary storage chamber) of the inclined unloading and preheating channel through the magnetic disk. Since the partition plate is in the open state, the scrap steel slides freely into the scrap steel preheating zone (i.e., the lower preheating chamber) under the action of gravity. When the scrap steel preheating zone is full of scrap steel, the partition plate is closed to prevent the scrap steel from continuing to enter the preheating zone. At this time, high-temperature flue gas enters the scrap steel preheating zone from the melting furnace and exchanges heat with the scrap steel. The scrap steel gradually heats up under the action of the high-temperature flue gas, and finally achieves efficient preheating of the scrap steel. After the preheating is completed, the breathable material blocking mechanism is opened, and the scrap steel falls into the melting furnace under the action of gravity. Steel melting stage: After the preheated scrap steel enters the melting furnace, the burner combustion rapid heating device (i.e., heating burner) is turned on. The burner adopts a certain power and uses the high-temperature flame generated by the combustion of natural gas to quickly heat the scrap steel accumulated above the molten steel. Simultaneously, the electromagnetic induction rapid melting device (i.e., electromagnetic heater) heats the molten steel at maximum power, accelerating the melting of the scrap steel through heat transfer from the molten steel. During the heating process, the furnace's molten steel level is continuously monitored. When there is no exposed scrap steel, the heating burner is closed, the retaining claw is opened, and new scrap steel is added. After adding, the retaining claw is closed, and the heating burner is reopened to preheat the newly added exposed scrap steel. During the tapping phase, when the molten steel reaches the tapping conditions, a ladle is placed below the melt outlet. Acetylene is used to burn through the melt outlet, and the molten steel flows into the ladle under the action of gravity. As the molten steel flows out, the molten steel level gradually decreases. When the molten steel level falls below the tapping step, tapping is stopped, and the melt outlet is blocked with drainage sand, completing the tapping process.

[0062] In the present invention, continuous production can be achieved by simultaneously providing a material barrier and a breathable material barrier mechanism in the inclined unloading and preheating channels. An example of a specific feeding process is as follows: During the first furnace, the material barrier claw is closed, the material barrier is opened, and a magnetic disk is used to suck the scrap steel into the scrap steel storage area (i.e., the upper temporary storage chamber). The scrap steel is allowed to freely slide into the scrap steel preheating area (i.e., the lower preheating chamber) until the scrap steel preheating area is loaded with 0.4G tons of scrap steel (G is the nominal capacity of the steel melting furnace), after which the material barrier is closed. At this point, the magnetic disk continues to be used to suck the scrap steel into the scrap steel storage area, and the material barrier claw is opened to allow the scrap steel to slide into the melting furnace. After 0.3G tons of scrap steel is loaded into the scrap steel storage area, the magnetic disk no longer sucks the scrap steel. When the infrared detector (i.e., thermal imager) on the top of the furnace cover shows that the scrap steel has melted and no scrap steel is exposed, the material barrier claw is opened to allow the preheated 0.3G tons of scrap steel to slide into the furnace, and then the material barrier claw is closed. Open the partition plate to allow the 0.3G tons of scrap steel in the scrap steel storage area to automatically slide into the scrap steel preheating area, and then close the partition plate. The magnetic disk continues to absorb 0.3G tons of scrap steel into the scrap steel storage area. When the infrared detector's image recognition shows that the scrap steel has melted again, open the material blocking claw and add the preheated 0.3G tons of scrap steel into the steel melting furnace. Then, close the material blocking claw and open the partition plate, and the 0.3G tons of scrap steel will slide into the scrap steel preheating area to continue preheating. After the steel is tapped, it will be added to the steel melting furnace for the next batch. When smelting the first batch, it is necessary to add materials in three batches, with the amount of scrap steel added being 0.4G tons, 0.3G tons, and 0.3G tons respectively. Among them, the first 0.4G tons of scrap steel was not preheated, and the next two additions were of preheated scrap steel. For other batches, due to the steel retention operation, the material blocking claw is directly opened at the beginning of smelting to allow the scrap steel that has been preheated in the previous batch to slide into the steel melting furnace. Then, the blocking claw is closed and the material barrier is opened, allowing the scrap steel in the scrap steel storage area to slide into the scrap steel preheating area. Then, the material barrier is closed, and the magnetic disk continues to suck 0.3G tons of scrap steel into the scrap steel storage area for standby use. In summary, the scrap steel storage area and the scrap steel preheating area in the preheating device are ensured to be filled with scrap steel. When the infrared detector image recognition shows that scrap steel can be added, the scrap steel in the scrap steel preheating area is added to the melting furnace, and the scrap steel in the scrap steel storage area slides into the scrap steel preheating area. The magnetic disk sucks the scrap steel into the scrap steel storage area for standby use, and this cycle repeats.

[0063] In the present invention, the scrap preheating temperature is related to many factors, and it is difficult to predict and control the scrap preheating temperature. The following analyzes the influence of various factors on the scrap preheating temperature: First, the inclined feeding and preheating channel α affect the state of the scrap in the channel, and thus affect the contact area A between the scrap and the flue gas. The contact area A can be expressed as , where k A is the contact area influence coefficient (experience value, generally 0.01~0.1), A0 is the contact area in the horizontal state. Secondly, the distance d between the blocking claws and the negative pressure P at the exhaust port out Influence of flue gas flow rate v g , which in turn affects heat transfer. The combined effect of the two factors leads to the flue gas velocity vg It can be expressed as , where k3 is the flue gas velocity influence coefficient, is the smoke resistance coefficient (measured value or empirical value, generally 0.5~1.5), is the flue gas density. The steel melting furnace adopts a slightly negative pressure operation, preferably negative pressure P out Controlled within the range of 0 to -100 Pa. The flue gas temperature at the outlet is T out , inlet flue gas temperature T in Influence: When the melting furnace is in a stable condition, the inlet flue gas temperature T in Keep constant, generally believed to be up to 1200℃; outlet flue gas temperature T out The flue gas temperature at the exhaust port should not be too high, as it will result in low heat utilization rate. It is usually controlled at It is appropriate ( is the target preheating temperature of scrap steel). In addition, according to the heat balance, within a certain time t, the heat absorbed by the scrap steel is equal to the heat transferred to the scrap steel by the flue gas. Therefore, the scrap steel preheating temperature T s (Assuming the scrap temperature is uniform, the average scrap temperature is used instead) The calculation formula is as follows:

[0064] = .

[0065] From this we can get:

[0066] ……(IV).

[0067] In formula (IV), k3 is the flue gas velocity influence coefficient, which is 0.8~2.0. h is the heat transfer coefficient between scrap steel and flue gas, which is 15~80W / (m 2 ·K). d is the distance between two adjacent retaining claws of the air-permeable retaining mechanism, cm. out is the negative pressure at the exhaust port, Pa. γ is the smoke resistance coefficient. ρ g is the smoke density, g / cm 3 D is the diameter of the smoke outlet, cm. p is the specific heat capacity of flue gas, J / (kg·k). t is the duration of the unit time period, ranging from 60 to 600 seconds. in is the initial temperature of the flue gas, °C. out is the flue gas temperature at the exhaust port, °C. m s is the mass of steel, kg. C s T is the specific heat capacity of steel, J / (kg·k). s,i is the temperature of scrap steel before the current time period, ℃. is the temperature of scrap steel after the current time period, ℃ (i is an integer greater than or equal to 0, and T s,0 is the measured value, ranging from 10 to 30°C). The real-time preheating temperature of the steel after different time periods is calculated using formula (IV).

[0068] In the present invention, the process of regulating the scrap preheating temperature in the inclined unloading and preheating channel is roughly as follows: During the smelting process in the melting furnace, a slight negative pressure (0 to -100Pa) is maintained at the smoke outlet. High-temperature flue gas of about 1200°C is generated in the furnace and enters the lower preheating chamber through the gap between the material blocking claws. The high-temperature flue gas penetrates the scrap steel and exchanges heat with the scrap steel, causing the scrap steel to be in a state of continuous heating. When the scrap steel preheating temperature reaches the target temperature, the negative pressure at the smoke outlet is reduced, and the scrap steel preheating system is in insulation mode. The specific scrap steel preheating temperature control process is as follows:

[0069] 1) Input various parameters, including: inclined feeding and preheating channel α, distance between blocking claws d, heat transfer coefficient between scrap steel and flue gas h, contact area between scrap steel and flue gas A0, scrap steel mass m s , scrap steel specific heat capacity C s , exhaust duct diameter D, flue gas specific heat capacity C p , steel size influence coefficient k1, flue gas velocity influence coefficient k3, flue gas resistance coefficient , smoke density , adjust the pressure difference , time interval , inlet flue gas temperature T in =1200℃, initial scrap temperature T s,0 =25℃;

[0070] 2) Obtain the time interval based on the monitoring device The outlet negative pressure P out , outlet flue gas temperature T out , calculate the scrap preheating temperature T s,i , and calculate the difference between the scrap preheating temperature and the target preheating temperature, that is, .

[0071] 3) If , that is, the average temperature of the scrap steel is lower than the target value and needs to be heated. At this time, first determine whether the outlet flue gas temperature is overheated to avoid heat loss. , indicating that the outlet flue gas temperature is not over-temperature, at this time adjust the fan power to increase the outlet negative pressure, that is The flue gas flow rate increases, and the heat transferred to the scrap steel in a certain period of time increases, which is conducive to the scrap steel temperature rise. It should be noted that in order to maintain low negative pressure operation, if the negative pressure , then take ;like , indicating that the outlet flue gas temperature is over-temperature, at this time adjust the fan power to reduce the outlet negative pressure, that is The flue gas flow rate is reduced, and after the scrap steel absorbs heat, the outlet flue gas temperature naturally decreases. Similarly, in order to maintain a slightly negative pressure operation, if , then take .

[0072] 4) If , that is, the average temperature of the scrap steel has reached the target value, and only needs to be kept warm, and the preheated scrap steel is ready to be added to the steel melting furnace at any time. At this time, set And keep stable until the preheating of scrap steel in this heat is completed.

[0073] It should be noted that the numerical values ​​in the above statements are merely exemplary values ​​for the purpose of illustrating the technical solution, and are not intended to limit the technical solution claimed in the present invention. Furthermore, it should be noted that all formulas or models in the present invention are obtained by fitting the inventors based on experiments and engineering applications, and all calculations are calculated by substituting the converted numerical values ​​into the formulas after conversion according to the prescribed units (after conversion, only the numerical values ​​are substituted into the formulas without the units; the units are used only to adjust the magnitude of the numerical values).

[0074] In the present invention, the length of the inclined feeding and preheating channel is 0.3 to 100 m, preferably 0.5 to 80 m, and more preferably 1 to 50 m. The width of the inclined feeding and preheating channel is 0.3 to 30 m, preferably 0.5 to 20 m, and more preferably 1 to 15 m. The depth of the inclined feeding and preheating channel is 0.3 to 15 m, preferably 0.5 to 10 m, and more preferably 1 to 8 m.

[0075] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0076] 1: The system and method of the present invention can greatly improve energy utilization efficiency: the traditional scrap preheating method cannot effectively determine the scrap preheating temperature, and the outlet negative pressure control is inaccurate, resulting in a large amount of high-temperature flue gas heat not being utilized, causing energy waste. The present invention optimizes the inclination angle and the spacing between the material blocking claws, and accurately controls the temperature and pressure during the scrap preheating process, so that the scrap and the flue gas are optimally matched. It has been verified that for every ton of scrap preheated, the natural gas consumption of the steel melting furnace is reduced by about 10 cubic meters, and the energy utilization efficiency is improved by about 20%, which can save a lot of production costs.

[0077] 2. The system and method of the present invention significantly improve scrap preheating: Traditional preheating methods cause some scrap to accumulate in the trough, resulting in uneven heating and a temperature deviation of up to ±200°C after preheating. The present invention adapts the scrap characteristics to the tilt angle to avoid scrap accumulation. The precise spacing of the retaining claws ensures the permeability of high-temperature flue gas, reducing the scrap temperature deviation to ±20°C. This not only increases the scrap preheating temperature, but also reduces the preheating temperature differences between different scrap pieces, providing better raw material conditions for the subsequent smelting process.

[0078] 3. This invention significantly reduces operating costs: Traditional preheating equipment that uses a motor-driven device to assist in scrap movement, with a 50kW motor operating 10 hours per day, can incur daily electricity costs of up to 500 yuan (calculated at 1 yuan per kilowatt-hour for industrial electricity). By optimizing the inclination angle, this invention allows the scrap to slide naturally under gravity, eliminating the need for a motor-driven device. This can save up to 180,000 yuan in electricity costs annually. This not only reduces operating energy consumption but also lowers the cost of purchasing and maintaining the motor-driven device, bringing significant economic benefits to the company.

[0079] 4: The present invention can greatly enhance the operational stability and life of the equipment: In traditional shaft-type scrap preheating devices, the scrap steel falls too quickly, which has a great impact on the material retaining claws and the material trough. According to statistics, the material retaining claws are damaged an average of 3 times per month, and the material trough requires two major repairs per year. The technical solution of the present invention reduces the impact of scrap steel on the material retaining claws and the material trough through a reasonable inclination angle, reducing the wear and fatigue of equipment components. The average number of damages to the material retaining claws per month is reduced to 1, and the material trough only requires one major repair per year. The overall service life of the equipment is significantly extended, and the equipment maintenance and replacement costs are greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Figure 1 Schematic diagram of the overall structure of the system of the present invention.

[0081] Figure 2 This is a structural diagram of the air-permeable material blocking mechanism of the present invention when it is a material blocking claw.

[0082] Figure 3 Schematic diagram of the connection relationship between the control device of the present invention and other components.

[0083] Figure 4 Schematic diagram of the preheating control process of the method of the present invention.

[0084] Figure 5 The figure is a schematic diagram of the continuous feeding process of the method of the present invention.

[0085] Figure markings: 1: inclined unloading and preheating channel; 101: breathable material blocking mechanism; 102: material blocking plate; 103: upper temporary storage chamber; 104: lower preheating chamber; 105: smoke exhaust port; 106: temperature monitoring device; 107: pressure control device; 108: material blocking drive motor; 109: material blocking drive motor; 1011: cooling medium channel; 1012: cooling medium inlet; 1013: cooling medium outlet; 2: melting furnace; 201: melt outlet; 3: heating device; 301: heating burner; 302: electromagnetic heater; 4: lifting angle adjustment mechanism; 401: hydraulic cylinder; 402: lifting support rod; 5: thermal imager; 6: control device. DETAILED DESCRIPTION

[0086] The technical solutions of the present invention are illustrated below with examples, and the scope of protection requested by the present invention includes but is not limited to the following embodiments.

[0087] A system for preheating and melting solid materials, the system comprising an inclined feeding and preheating channel 1 and a melting furnace 2. The bottom outlet of the inclined feeding and preheating channel 1 is connected to the upper part of the furnace chamber of the melting furnace 2. A breathable material blocking mechanism 101 is provided at the bottom end of the inclined feeding and preheating channel 1. A melt outlet 201 is provided at the bottom of the melting furnace 2. A heating device 3 is also provided in the melting furnace 2. Preferably, the inclination angle of the inclined feeding and preheating channel 1 is less than 90°, preferably 5° to 55°, and more preferably 10° to 80°.

[0088] Preferably, a material partition plate 102 is provided within the inclined material discharge and preheating channel 1, dividing the interior of the inclined material discharge and preheating channel 1 into an upper temporary storage chamber 103 and a lower preheating chamber 104. A smoke exhaust port 105 is provided on the upper wall of the lower preheating chamber 104. A breathable material blocking mechanism 101 is provided at the bottom of the lower preheating chamber 104.

[0089] Preferably, a temperature monitoring device 106 and / or a pressure control device 107 are further provided at the smoke exhaust port 105. Preferably, the temperature monitoring device 106 is a thermocouple. The pressure control device 107 is composed of a pressure sensor and a speed-regulating fan.

[0090] Preferably, the top end of the partition plate 102 passes through the top wall of the inclined material unloading and preheating channel 1 and extends to the outside of the inclined material unloading and preheating channel 1. A partition drive motor 108 connected to the top end of the partition plate 102 is provided on the top wall surface of the inclined material unloading and preheating channel 1. The partition drive motor 108 drives the partition plate 101 to rise and fall in a direction perpendicular to the axis of the inclined material unloading and preheating channel 1, thereby realizing the connection or isolation between the upper temporary storage chamber 103 and the lower preheating chamber 104.

[0091] Preferably, the breathable material blocking mechanism 101 is a material blocking claw. A material blocking drive motor 109 connected to the breathable material blocking mechanism 101 is also provided at the bottom end of the lower preheating chamber 104. The material blocking drive motor 109 drives the breathable material blocking mechanism 101 to swing up and down, thereby enabling the breathable material blocking mechanism 101 to block and open the inclined material discharge and the bottom outlet of the preheating channel 1. Preferably, the number of claws of the breathable material blocking mechanism 101 is 2 to 30, preferably 3 to 20. The width of a single claw is 2 to 20 cm, preferably 3 to 10 cm. The spacing between two adjacent claws is 1 to 15 cm, preferably 2 to 8 cm.

[0092] Preferably, a cooling medium channel 1011 and a cooling medium inlet 1012 and a cooling medium outlet 1013 connected to the cooling medium channel 1011 are further provided inside the breathable material blocking mechanism 101 .

[0093] Preferably, the heating device 3 includes a heating burner 301 and an electromagnetic heater 302. The heating burner 301 is disposed in the upper portion of the inner cavity of the melting furnace 2. The electromagnetic heater 302 is disposed in the lower portion of the inner cavity of the melting furnace 2. Preferably, the heating burner 301 and the electromagnetic heater 302 are both disposed on a side away from the melt outlet 201. Preferably, the feed end of the melt outlet 201 is an overflow design that is higher than the bottom wall of the inner cavity of the melting furnace 2.

[0094] Preferably, the system further comprises a lifting angle adjustment mechanism 4. The lifting angle adjustment mechanism 4 comprises a hydraulic cylinder 401 and a lifting support rod 402. The hydraulic cylinder 401 is arranged on the ground below the inclined blanking and preheating channel 1. The bottom end of the lifting support rod 402 is connected to the piston rod of the hydraulic cylinder 401, and the top end of the lifting support rod 402 is connected to the upper bottom wall of the inclined blanking and preheating channel 1. The bottom end of the inclined blanking and preheating channel 1 is hinged to the furnace wall of the melting furnace 2. The hydraulic cylinder 401 drives the inclined blanking and preheating channel 1 to rotate in the vertical direction with its bottom end as the rotation center through the lifting and lowering of the lifting support rod 402, thereby adjusting the inclination angle of the inclined blanking and preheating channel 1.

[0095] Preferably, the system further comprises a thermal imager 5 , which is arranged on the top wall of the inner cavity of the melting furnace 2 .

[0096] Preferably, the system also includes a control device 6, which is respectively associated with the temperature monitoring device 106, the pressure control device 107, the material isolation drive motor 108, the material blocking drive motor 109, the heating device 3, the lifting angle adjustment mechanism 4, and the thermal imager 5 to coordinate and control their working states.

[0097] Example 1

[0098] like Figure 1-3 As shown, a system for preheating and melting solid materials includes an inclined feeding and preheating channel 1 and a melting furnace 2. The bottom outlet of the inclined feeding and preheating channel 1 is connected to the upper portion of the furnace chamber of the melting furnace 2. A breathable material retaining mechanism 101 is provided at the bottom end of the inclined feeding and preheating channel 1. A melt outlet 201 is provided at the bottom of the melting furnace 2. A heating device 3 is also provided within the melting furnace 2.

[0099] Example 2

[0100] Example 1 was repeated, except that the inclined feeding and preheating channel 1 had an inclination angle of 5° to 85°.

[0101] Example 3

[0102] Example 2 was repeated, except that the inclination angle of the inclined feeding and preheating channel 1 was 10° to 80°.

[0103] Example 4

[0104] Example 3 was repeated, except that the inclined angle of the inclined feeding and preheating channel 1 was 30° to 60°.

[0105] Example 5

[0106] Example 4 was repeated, except that a material partition plate 102 was installed within the inclined material discharge and preheating channel 1, dividing the interior of the inclined material discharge and preheating channel 1 into an upper temporary storage chamber 103 and a lower preheating chamber 104. A smoke exhaust port 105 was provided in the upper wall of the lower preheating chamber 104. A breathable material blocking mechanism 101 was installed at the bottom of the lower preheating chamber 104.

[0107] Example 6

[0108] Example 5 is repeated, except that a temperature monitoring device 106 and a pressure control device 107 are further provided at the smoke exhaust port 105 .

[0109] Example 7

[0110] Example 6 is repeated, except that the temperature monitoring device 106 is a thermocouple. The pressure control device 107 is composed of a pressure sensor and a speed-regulating fan.

[0111] Example 8

[0112] Example 7 is repeated, except that the top end of the partition plate 102 passes through the top wall of the inclined unloading and preheating channel 1 and extends to the outside of the inclined unloading and preheating channel 1. A partition drive motor 108 connected to the top end of the partition plate 102 is provided on the top wall surface of the inclined unloading and preheating channel 1. The partition drive motor 108 drives the partition plate 101 to rise and fall in a direction perpendicular to the axis of the inclined unloading and preheating channel 1, thereby achieving connection or isolation between the upper temporary storage chamber 103 and the lower preheating chamber 104.

[0113] Example 9

[0114] Example 8 is repeated, except that the breathable material blocking mechanism 101 is a material blocking claw. A material blocking drive motor 109 connected to the breathable material blocking mechanism 101 is further provided at the bottom end of the lower preheating chamber 104. The material blocking drive motor 109 drives the breathable material blocking mechanism 101 to swing up and down, thereby achieving the blocking and opening of the breathable material blocking mechanism 101 for the inclined material discharge and the bottom outlet of the preheating channel 1.

[0115] Example 10

[0116] Example 9 was repeated, except that the number of the blocking claws of the air-permeable material blocking mechanism 101 was 8. The width of a single blocking claw was 5 cm, and the distance between two adjacent blocking claws was 4 cm.

[0117] Example 11

[0118] Example 10 is repeated, except that a cooling medium channel 1011 and a cooling medium inlet 1012 and a cooling medium outlet 1013 connected to the cooling medium channel 1011 are further provided inside the air-permeable material blocking mechanism 101 .

[0119] Example 12

[0120] Example 11 is repeated, except that the heating device 3 includes a heating burner 301 and an electromagnetic heater 302. The heating burner 301 is arranged at the upper part of the inner cavity of the melting furnace 2. The electromagnetic heater 302 is arranged at the lower part of the inner cavity of the melting furnace 2.

[0121] Example 13

[0122] Example 12 is repeated, except that the heating burner 301 and the electromagnetic heater 302 are both arranged on the side away from the melt outlet 201.

[0123] Example 14

[0124] Example 13 is repeated, except that the feed end of the melt outlet 201 is designed as an overflow type that is higher than the bottom wall of the inner cavity of the melting furnace 2.

[0125] Example 15

[0126] Example 14 is repeated, except that the system further includes a lifting angle adjustment mechanism 4. The lifting angle adjustment mechanism 4 includes a hydraulic cylinder 401 and a lifting support rod 402. The hydraulic cylinder 401 is disposed on the ground below the inclined material discharge and preheating channel 1. The bottom end of the lifting support rod 402 is connected to the piston rod of the hydraulic cylinder 401, and the top end of the lifting support rod 402 is connected to the upper bottom wall of the inclined material discharge and preheating channel 1. The bottom end of the inclined material discharge and preheating channel 1 is hinged to the furnace wall of the melting furnace 2. The hydraulic cylinder 401 drives the inclined material discharge and preheating channel 1 to rotate in the vertical direction with its bottom end as the rotation center through the lifting and lowering of the lifting support rod 402, thereby adjusting the inclination angle of the inclined material discharge and preheating channel 1.

[0127] Example 16

[0128] Example 15 is repeated, except that the system further includes a thermal imager 5 , which is disposed on the top wall of the inner cavity of the melting furnace 2 .

[0129] Example 17

[0130] Repeat Example 16, except that the system also includes a control device 6, which is respectively associated with the temperature monitoring device 106, the pressure control device 107, the material isolation drive motor 108, the material blocking drive motor 109, the heating device 3, the lifting angle adjustment mechanism 4, and the thermal imager 5 to coordinate and control their working states.

[0131] Example 18

[0132] The system described in Example 17 is used to preheat and melt scrap steel:

[0133] Adjustment of the tilt angle of the inclined unloading and preheating channel 1: Under the current working conditions, it is detected that: the total mass of the scrap steel to be processed is m s The weight of the scrap steel to be processed is 300 kg, the average length l0 of the scrap steel to be processed is about 0.8 m, the average width w0 of the scrap steel to be processed is about 0.5 m, the average thickness h0 of the scrap steel to be processed is about 0.2 m, and the friction coefficient between the scrap steel to be processed and the inclined unloading and preheating channel 1 is is 0.55, the steel size influence coefficient k1 is 0.4, the collision time △t between the steel and the breathable material blocking mechanism 101 is about 0.6s, the force coefficient k2 of the material blocking mechanism is 40, and the maximum sliding speed of the steel allowed by the working conditions is 5m / s, the maximum load of the breathable material blocking mechanism 101 allowed by the working conditions The weight of the steel sliding speed is 8000N. is 0.2, the weight of the force factor of the breathable material blocking mechanism 101 is The weight of the steel size factor is 0.7. If it is 0.1, then the optimal tilt angle corresponding to the comprehensive evaluation factor E value in the range of 30~60° is calculated according to formulas (I), (II), and (III). The lifting angle adjustment mechanism 4 is started, and the lifting support rod 402 is driven by the hydraulic cylinder 401 so that the tilt angle of the inclined unloading and preheating channel 1 is 45 degrees.

[0134] Preheating and melting: first open the partition plate 102 and the breathable material blocking mechanism 101, suck 400kg of scrap steel into the upper temporary storage chamber 103 through the magnetic disk, and then make it slide down automatically until it enters the melting furnace 2; then close the breathable material blocking mechanism 101 and suck 300kg of scrap steel into the upper temporary storage chamber 103 through the magnetic disk, and then make it slide down automatically into the lower preheating chamber 104; finally, close the partition plate 102 and continue to suck 300kg of scrap steel into the upper temporary storage chamber 103 for temporary storage through the magnetic disk. Then, the heating burner 301 is started to heat and melt the 400kg scrap steel in the melting furnace 2. When the accumulated molten steel at the bottom of the furnace is submerged in the heating range of the electromagnetic heater 302, the electromagnetic heater 302 is started to further melt the scrap steel. When the thermal imager 5 detects that there is no exposed scrap steel in the molten steel, the breathable material blocking mechanism 101 is opened to allow the preheated 300kg scrap steel to slide down into the melting furnace 2 for melting. Then, the breathable material blocking mechanism 101 is closed and the partition plate 102 is opened to allow the 300kg scrap steel to be preheated to slide down into the lower preheating chamber 104 for preheating. Then, the partition plate 102 is closed and the 300kg scrap steel is sucked into the upper temporary storage chamber 103 for temporary storage through the magnetic disk. The above operation is repeated until all the scrap steel is melted.

[0135] During the preheating process of scrap steel: set the target preheating temperature T of the current steel obj The flue gas velocity influence coefficient k3 is 1.5, the distance d between two adjacent blocking claws of the breathable blocking mechanism (101) is 4 cm, the flue gas resistance coefficient γ is 0.9, and the flue gas density ρ g 0.0012g / cm 3 The diameter D of the smoke exhaust port 105 is 50 cm, and the specific heat capacity of the smoke is C p is 1100 J / (kg·k), the initial temperature of the flue gas is T in 1200℃, m s The mass of steel is 300kg, and the specific heat capacity of steel is C s The flue gas temperature T at the exhaust port 105 is detected by the temperature monitoring device 106. out The negative pressure P at the smoke exhaust port 105 is detected by the pressure sensor of the pressure control device 107. out is -50 Pa. The initial temperature of scrap steel is T s,0If the temperature is 25℃, then under the condition that the unit time period t is 60s, the scrap steel temperature T after preheating (the total preheating time is about 930s) is calculated by formula (IV): s,i About 610℃. s,i >T obj , indicating that the current preheating temperature of the steel has reached the target value and only the insulation operation is required. That is, the speed regulating fan of the pressure control device 107 controls the negative pressure P at 105. out When there is no exposed scrap steel in the melting furnace 2, the air-permeable material blocking mechanism 101 can be opened to slide the preheated scrap steel into the melting furnace 2 for melting. According to statistics (considering only the continuous production process), in this embodiment, the average gas consumption per ton of scrap steel is about 24m 3 The average power consumption is about 59kW·h, and the average time consumption is about 0.86h.

[0136] Traditional horizontal channel preheating is limited by its structure, with a preheating temperature of only 300°C to 400°C. Pure burner combustion preheating of scrap steel has a fast heating rate, but low thermal efficiency (approximately 40%), and it is difficult to raise the scrap preheating temperature to approximately 800°C. This embodiment, however, can melt the scrap steel to 1600°C. Pure electromagnetic induction heating is limited by the low initial scrap temperature and slow heating rate. While it can heat the scrap steel to melting, the overall preheating cycle is long, approximately 1.2 hours per ton of scrap steel. Furthermore, pure electromagnetic induction heating lacks front-end scrap preheating, leaving much of the high-temperature flue gas heat unabsorbed by the scrap steel, resulting in low thermal efficiency (approximately 65%). This embodiment achieves a thermal efficiency of 68.1%, while the thermal efficiency of traditional horizontal channel heating is generally below 50%.

Claims

1. A system for preheating and melting solid materials, characterized by: The system comprises an inclined material discharging and preheating channel (1) and a melting furnace (2); the bottom outlet of the inclined material discharging and preheating channel (1) is connected to the upper part of the furnace chamber of the melting furnace (2); a breathable material blocking mechanism (101) is provided at the bottom end of the inclined material discharging and preheating channel (1); a melt outlet (201) is provided at the bottom of the melting furnace (2); a heating device (3) is further provided in the melting furnace (2); preferably, the inclination angle of the inclined material discharging and preheating channel (1) is less than 90°, preferably 5°~85°, and more preferably 10°~80°.

2. The system according to claim 1, wherein: A material partition plate (102) is provided in the inclined material discharge and preheating channel (1) to separate the inner cavity of the inclined material discharge and preheating channel (1) into an upper temporary storage cavity (103) and a lower preheating cavity (104); a smoke exhaust port (105) is provided on the upper end cavity wall of the lower preheating cavity (104); and a breathable material blocking mechanism (101) is provided at the bottom end of the lower preheating cavity (104); Preferably, a temperature monitoring device (106) and / or a pressure control device (107) is further provided at the smoke exhaust port (105); preferably, the temperature monitoring device (106) is a thermocouple; and the pressure control device (107) is composed of a pressure sensor and a speed-regulating fan.

3. The system according to claim 2, characterized in that: The top end of the partition plate (102) passes through the top wall of the inclined material unloading and preheating channel (1) and extends to the outside of the inclined material unloading and preheating channel (1); a partition drive motor (108) connected to the top end of the partition plate (102) is provided on the top wall surface of the inclined material unloading and preheating channel (1), and the partition plate (101) is driven by the partition drive motor (108) to rise and fall in a direction perpendicular to the axis of the inclined material unloading and preheating channel (1) to achieve communication or isolation between the upper temporary storage chamber (103) and the lower preheating chamber (104).

4. The system according to any one of claims 1 to 3, characterized in that: The breathable material blocking mechanism (101) is a material blocking claw; a material blocking drive motor (109) connected to the breathable material blocking mechanism (101) is further provided at the bottom end of the lower preheating chamber (104), and the material blocking drive motor (109) drives the breathable material blocking mechanism (101) to perform an arc-shaped lifting and lowering, thereby realizing the breathable material blocking mechanism (101) blocking and opening the inclined material discharge and the bottom end outlet of the preheating channel (1); preferably, the number of the material blocking claws of the breathable material blocking mechanism (101) is 2 to 30, preferably 3 to 20; the width of a single material blocking claw is 2 to 20 cm, preferably 3 to 10 cm; the spacing between two adjacent material blocking claws is 1 to 15 cm, preferably 2 to 8 cm; Preferably, a cooling medium channel (1011) and a cooling medium inlet (1012) and a cooling medium outlet (1013) connected to the cooling medium channel (1011) are further provided inside the air-permeable material blocking mechanism (101).

5. The system according to any one of claims 1 to 4, characterized in that: The heating device (3) includes a heating burner (301) and an electromagnetic heater (302); the heating burner (301) is arranged at the upper part of the inner cavity of the melting furnace (2); the electromagnetic heater (302) is arranged at the lower part of the inner cavity of the melting furnace (2); preferably, the heating burner (301) and the electromagnetic heater (302) are both arranged on a side away from the melt outlet (201); preferably, the feed end of the melt outlet (201) is an overflow design that is higher than the bottom wall of the inner cavity of the melting furnace (2).

6. The system according to any one of claims 1 to 5, characterized in that: The system further comprises a lifting angle adjustment mechanism (4); the lifting angle adjustment mechanism (4) comprises a hydraulic cylinder (401) and a lifting support rod (402); the hydraulic cylinder (401) is arranged on the ground below the inclined material discharge and preheating channel (1); the bottom end of the lifting support rod (402) is connected to the piston rod of the hydraulic cylinder (401), and the top end of the lifting support rod (402) is connected to the upper bottom wall of the inclined material discharge and preheating channel (1); the bottom end of the inclined material discharge and preheating channel (1) is hinged to the furnace wall of the melting furnace (2); the hydraulic cylinder (401) drives the inclined material discharge and preheating channel (1) to rotate in the vertical direction with its bottom end as the rotation center through the lifting and lowering of the lifting support rod (402), thereby realizing the adjustment of the inclined angle of the inclined material discharge and preheating channel (1); and / or The system also includes a thermal imager (5), which is arranged on the top wall of the inner cavity of the melting furnace (2); Preferably, the system further comprises a control device (6), wherein the control device (6) is respectively associated with the temperature monitoring device (106), the pressure control device (107), the material separation drive motor (108), the material blocking drive motor (109), the heating device (3), the lifting angle adjustment mechanism (4), and the thermal imager (5) and coordinately controls their working states.

7. A method for preheating molten steel or a method for preheating molten steel using the system according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: S1. First, determine the inclination angle of the inclined feeding and preheating channel (1) according to the basic properties of the current steel; then directly feed the steel into the melting furnace (2) through the inclined feeding and preheating channel (1) for melting; S2. During the smelting process, steel is added to the inclined feeding and preheating channel (1) and the added steel is temporarily retained in the inclined feeding and preheating channel (1) through the air-permeable material retaining mechanism (101); S3, transporting the hot flue gas in the melting furnace (2) to the inclined unloading and preheating channel (1) to preheat the retained steel; S4. When the steel in the melting furnace (2) is smelted, the molten steel is discharged through the molten steel outlet, and the steel that has been preheated in the inclined discharge and preheating channel (1) is added to the melting furnace (2) to continue smelting; and steps S2 to S4 are performed in this cycle.

8. The method according to claim 7, wherein: In step S1, the inclination angle of the inclined blanking and preheating channel (1) is determined according to the basic properties of the current steel material, including: S101. Establish an equation for calculating the sliding speed of the steel at different inclination angles based on the average size of the current steel. The equation is as follows: （I）； In formula (I), v s is the sliding speed of the steel, m / s; The different tilt angles of the inclined feeding and preheating channel (1), rad; is the friction coefficient when the steel slides down, and the value is 0.2~0.6; g is the acceleration due to gravity, and the value is 9.8m / s 2 k1 is the steel size influence coefficient, ranging from 0.1 to 5.0; l0 is the average length of the steel, m; w0 is the average width of the steel, m; h0 is the average thickness of the steel, m; the sliding speed of the steel at different inclination angles is calculated according to formula (I); S102. According to the mass and average size of the steel material, a calculation equation for the impact force on the air-permeable material retaining mechanism (101) at different sliding speeds is established. The calculation equation is as follows: (II); In formula (II), F is the impact force on the breathable material blocking mechanism (101) at different sliding speeds, N; m s is the mass of the steel, kg; △t is the collision time between the steel and the breathable material retaining mechanism (101), s; k2 is the force coefficient of the material retaining mechanism, which ranges from 10 to 100; the impact force on the breathable material retaining mechanism (101) at different sliding speeds is calculated according to formula (II); S103, using the sliding speed of the steel material at the same inclination angle of the inclined unloading and preheating channel (1) and the impact force on the breathable material blocking mechanism (101) as independent variables to establish a comprehensive evaluation factor estimation model, the estimation model is as follows: (III); In formula (III), E is the comprehensive evaluation factor; is the maximum sliding speed of steel allowed by the working conditions, m / s; is the maximum bearing capacity of the breathable material retaining mechanism (101) allowed by the working conditions, N; , It is the optimal comprehensive parameter of steel size under ideal production conditions, with a value of 5~50; is the factor weight of steel decline rate, is the weight of the force factor of the breathable material retaining mechanism (101), is the weight of the steel size factor, where: w v +w F +w s =1, 、 、 are greater than 0 and less than 1; different comprehensive evaluation factor values ​​are calculated according to formula (III), where the value corresponding to the comprehensive evaluation factor reaching the maximum value is The value is the inclination angle of the inclined unloading and preheating channel (1) under the current working condition.

9. The method according to claim 7 or 8, characterized in that: The method further comprises: during the smelting process, calculating the current real-time temperature of the steel material in real time according to the steel material preheating temperature calculation model, and adjusting the negative pressure at the smoke exhaust port (105) of the inclined material discharge and preheating channel (1) according to the change of the current real-time temperature of the steel material to reduce heat loss; wherein: the steel material preheating temperature calculation model is as follows: ……(IV); In formula (IV), k3 is the flue gas velocity influence coefficient, which is 0.8~2.0; d is the distance between two adjacent blocking claws of the breathable blocking mechanism (101), cm; P out is the negative pressure at the exhaust port (105), Pa; γ is the smoke resistance coefficient; ρ g is the smoke density, g / cm 3 ; D is the diameter of the smoke exhaust port (105), cm; C p is the specific heat capacity of flue gas, J / (kg·k); t is the duration of the unit time period, ranging from 60 to 600s; T in is the initial temperature of the flue gas, °C; T out is the flue gas temperature at the exhaust port (105), °C; m s is the mass of steel, kg; C s is the specific heat capacity of steel, J / (kg·k); T s,i is the temperature of scrap steel before the current time period, ℃; is the temperature of scrap steel after the current time period, ℃ (i is an integer greater than or equal to 0, and T s,0 is the measured value, ranging from 10 to 30°C); the real-time preheating temperature of the steel after different time periods is calculated by formula (IV); As a preference, the target preheating temperature of the current steel is set as T obj , ℃; then: like -T obj >0, indicating that the current preheating temperature of the steel has reached the target value and insulation operation is required; like -T obj ≤0, indicating that the current preheating temperature of the steel is lower than the target value and the temperature needs to be raised.

10. The method according to claim 9, characterized in that: The method further comprises: the heat preservation operation is: adjusting the smoke exhaust port (105) to a slight negative pressure through a pressure control device (107); the slight negative pressure is -5 to -20 Pa, preferably -10 to -15 Pa; and / or The heating operation is as follows: if the flue gas temperature T at the exhaust port (105) out -T obj ≤50℃, indicating that the exhaust gas temperature is not over-temperature, and the negative pressure at the exhaust port (105) needs to be increased through the pressure control device (107); if the exhaust gas temperature T out -T objj >50°C, indicating that the exhaust gas temperature has exceeded the upper limit, the negative pressure at the exhaust port (105) needs to be reduced by the pressure control device (107); the negative pressure is -5 to -120 Pa, preferably -10 to -100 Pa.

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