Closed hot air circulation furnace charge drying device

Abstract

The utility model relates to a closed hot air circulation furnace charge drying device, which belongs to the technical field of drying equipment and comprises a feed hopper, a box body, a discharge pipe, a drying pipe, a circulating fan, an electromagnetic heater, a mesh belt conveyor, a waste heat recovery pipe, a cyclone steam-water separator and the like. The drying pipe is fixed on a fixed bracket in the box body, and a plurality of air outlet holes are formed in the pipe wall; the circulating fan is fixed at one end of the drying pipe; a heating coil of the electromagnetic heater is wound and fixed on the outer pipe wall of the heating section of the drying pipe; the mesh belt conveyor is fixed on a fixed bracket in the box body; the waste heat recovery pipe is fixed to a fixing support in the box body, and a plurality of air inlet holes are formed in the pipe wall of the waste heat recovery pipe. And the cyclone steam-water separator is fixed and communicated with one end, extending out of the box body, of the waste heat recovery pipe and is communicated with the circulating fan. The waste heat recovery pipe, the cyclone type steam-water separator and the circulating fan are utilized, waste heat gas obtained after furnace burden is heated is heated again through the heating coil of the electromagnetic heater and then transferred into the drying pipe, the temperature of initial gas in the drying pipe is increased, and power consumption is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of drying equipment, in particular to a closed hot air circulation furnace material drying device. Background Art

[0002] In the actual process of producing rock wool using an electric melting furnace, on the one hand, every 1% increase in the moisture content of the charge will increase the power consumption of the electric melting furnace during the melting process by 3% (about 723kw.h of electricity is consumed for each ton of water vapor evaporated); on the other hand, when the charge is added to the melting furnace, since the environment inside the electric melting furnace is relatively sealed, the charge with excessive moisture content will instantly generate a large amount of water vapor in the furnace when it encounters the high temperature of the furnace. In the mildest case, it will cause the impedance parameters of the secondary circuit of the electric melting furnace to change sharply, and the input power in the furnace may change accordingly, which may make the rock wool molten liquid flow unstable, the flow temperature unstable, the production capacity unstable, the quality of the rock wool product deteriorate, and the energy consumption increase. In the worst case, it will cause accidents such as short circuit of the electrical circuit of the electric melting furnace and damage to the equipment.

[0003] Most of the existing material drying equipment uses firewood, coal, gas, resistance heating tubes, etc. as heat sources, and blows hot air into the equipment to be dried through fans. Traditional heating methods cause great pollution to the environment, have low hot air utilization, and are inconvenient to operate.

[0004] Therefore, how to provide a furnace charge drying device that is pollution-free, has high hot air utilization, good drying effect, is easy to automate and operate, and can enable stable production of electric melting furnaces is a technical problem that technical personnel in this field urgently need to solve. Utility Model Content

[0005] The utility model provides a closed hot air circulation furnace charge drying device, which solves the technical problem of low hot air utilization rate of the existing furnace charge drying device.

[0006] The utility model solves the above technical problems with the following technical solutions: a closed hot air circulation furnace charge drying device, comprising: a box, a drying mechanism, a conveying mechanism and a waste heat recovery mechanism.

[0007] The top surface of the box body is provided with a feed hole and the lower side wall is provided with a discharge hole, the feed hole of the box body is fixed and connected with a feed hopper, and the discharge hole of the box body is fixed and connected with a discharge pipe; the drying mechanism includes a drying tube, a steam-water separator, a circulating fan and an electromagnetic heater, the drying tube is fixed on a fixed bracket in the box body and a plurality of air outlets are provided on the tube wall located in the box body; the circulating fan is fixed on one end of the drying tube extending out of the box body; the heating coil of the electromagnetic heater is wound and fixed on the outer tube wall of the drying tube extending out of the heating section of the box body; the conveying mechanism includes a mesh belt conveyor, the mesh belt conveyor is located in the box body and is fixed on the corresponding plurality of air outlets above the mesh belt conveyor. On the fixed bracket of the box body, the feed end of the mesh belt conveyor is connected with the discharge end of the feed hopper and its discharge end is connected with the feed end of the discharge pipe; the waste heat recovery mechanism includes a waste heat recovery pipe and a cyclone type steam-water separator, the waste heat recovery pipe is fixed on the fixed bracket of the box body corresponding to the upper side of the mesh belt conveyor, and a plurality of air inlet holes are arranged on the pipe wall of the waste heat recovery pipe extending into the box body; the cyclone type steam-water separator is fixed and connected to the end of the waste heat recovery pipe extending out of the box body and is connected to the circulating fan; the waste heat recovery pipe, the box body, the cyclone steam-water separator, the circulating fan and the connecting pipe between the cyclone steam-water separator and the circulating fan are all provided with an outer layer of insulation.

[0008] The beneficial effects of the utility model are:

[0009] 1. Use the mesh belt conveyor to fix the top of the drying pipe on the fixed bracket of the box body, so that the charge can be dried during the transportation, reducing the drying time and improving the drying efficiency;

[0010] 2. The waste heat recovery pipe is fixed on the fixed bracket in the box body corresponding to the top of the mesh belt conveyor, and a plurality of air inlet holes are arranged on the pipe wall extending into the box body. Since the cyclone steam-water separator is fixed at one end of the waste heat recovery pipe extending out of the box body, and the cyclone steam-water separator is connected with the circulating fan, the waste heat gas after heating the furnace charge can be heated again by the heating coil of the electromagnetic heater and then transferred to the drying tube, thereby increasing the temperature of the initial gas in the drying tube and reducing the power consumption of the electromagnetic heater;

[0011] 3. By using a cyclone steam-water separator connected to the waste heat recovery pipe and the circulating fan respectively, the moisture contained in the waste heat gas can be separated, thereby keeping the waste heat gas dry, allowing the waste heat gas to be recycled, improving the drying effect of the drying device, and achieving the purpose of further energy saving.

[0012] On the basis of the above technical solution, the present invention can also be improved as follows.

[0013] Furthermore, there are multiple drying tubes, circulating fans, electromagnetic heaters and mesh belt conveyors, and the multiple drying tubes and the multiple mesh belt conveyors are staggered and distributed along the height direction of the box body, and the discharge ends and feed ends of the mesh belt conveyors adjacent to each other along the height direction of the box body are connected, the feed end of the highest mesh belt conveyor is connected to the discharge end of the feed hopper, and the discharge end of the lowest mesh belt conveyor is connected to the feed end of the discharge pipe, and are firmly fixed on the bracket in the box body; the cyclone type steam-water separator is connected to the multiple circulating fans.

[0014] A further beneficial effect of the above-mentioned method is that multiple drying tubes and multiple mesh belt conveyors are distributed in the box body at intervals and staggered along the height direction of the box body. Since the discharge end and the feed end of the mesh belt conveyors adjacent to each other along the height direction of the box body are connected, an S-shaped conveying route can be formed between the multiple mesh belt conveyors, thereby extending the heating and drying path and improving the drying efficiency.

[0015] Furthermore, it also includes a debris collection mechanism, which includes a debris collection plate and a debris bucket, the debris collection plate is arranged below the mesh belt conveyor and its edge is fixed to the inner wall of the box body, the plate surface of the debris collection plate is tilted downward from its edge to its center and a debris outlet hole is provided at the lowest point of its center; the debris bucket is fixed on the upper part of the debris outlet hole.

[0016] The above-mentioned method has the further beneficial effect of: by arranging the debris collecting plate below the mesh belt conveyor and fixing its edge on the fixed bracket of the box body, the debris dropped on the mesh belt conveyor can be effectively collected; at the same time, the plate surface of the debris collecting plate is tilted downward from its edge to its center and the debris bucket is provided with a debris outlet hole at the lowest point of the center of the debris collecting plate, which can improve the debris discharge effect.

[0017] Furthermore, the slag collecting mechanism also includes a slag discharger, and the slag discharger is fixed at the slag outlet of the slag bucket through a flange.

[0018] The further beneficial effect of adopting the above is that the slag discharger is a star-shaped discharger, and the slag outlet flange of the slag bucket is connected to the star-shaped discharger. Usually, the structure of the star-shaped discharger is composed of a rotor impeller with several blades, a shell, a seal, a reducer, a motor, etc. In a system with a certain air pressure output, the star-shaped discharger can discharge materials to the outside evenly and continuously, and can also isolate the upper and lower air pressures of the star-shaped discharger to play a role in locking air. When the material in the slag bucket falls by its own weight and fills the gap between the blades, it can be quantitatively and continuously discharged at the bottom as the blades rotate. A temperature-resistant star-shaped discharger is preferred, and the temperature of the material it conveys can reach 280°C. Further, the slag collection mechanism also includes a slag arch breaker, which is fixed in the slag bucket and its blowing port is located between the slag outlet hole of the slag bucket and the slag inlet hole of the slag discharger.

[0019] The further beneficial effect of adopting the above is: when the material in the crushing bucket forms an arch, the blowing port of the arch breaker is a strong airflow of compressed gas that is suddenly ejected to directly rush into the blocked fault area where the bulk material is stored. This sudden release of the expansion shock wave overcomes the static friction of the material and can restore the flow of the arch-forming material in the crushing bucket. It uses the principle of aerodynamics, and the working medium is air. It has a differential pressure device and a quick exhaust valve that can be automatically controlled. It can instantly convert air pressure energy into air jet kinetic energy, and can generate a strong impact force. It is a clean, pollution-free, low-energy ideal clearing and soot blowing equipment. The arch breaker has the basic advantages of simple structure, safe and convenient use, large impact force, safety, energy saving, automatic control, simple operation, and no damage to the bin. It is currently the most ideal arch breaking and flow-aiding device.

[0020] Furthermore, the debris collection mechanism also includes a vibrator, and the vibrator is fixed on the debris collection plate.

[0021] A further beneficial effect of the above-mentioned method is that the debris is fixed on the debris collection plate by vibration, which can improve the debris discharge effect and avoid some debris remaining on the debris collection plate.

[0022] Furthermore, it also includes a humidity sensor, a temperature sensor and a controller, wherein the humidity sensor, the temperature sensor and the controller are all fixed on the box body, and the controller is electrically connected to the circulating fan, the electromagnetic heater, the mesh belt conveyor, the cyclone steam-water separator, the humidity sensor and the temperature sensor respectively.

[0023] Furthermore, it also includes a material level sensor, which is fixed in the feed hopper and electrically connected to a feeding conveyor that transports materials to the feed hopper.

[0024] Furthermore, the discharge pipe is arranged to be tilted downward in a direction away from the mesh belt conveyor.

[0025] Furthermore, it also includes a maintenance door, and the side wall of the box body is provided with an entry and exit hole; the maintenance door is hinged at the entry and exit hole of the box body and is provided with an observation hole, and transparent glass is fixed at the observation hole.

[0026] Furthermore, it also includes a support frame, which is located outside the box body. The circulating fan, the electromagnetic heater and the cyclone steam-water separator are all fixed on the external support frame, and all supporting points on the support frame are equipped with high-temperature resistant and shock-proof pads. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The utility model is a schematic diagram of the internal structure of a closed hot air circulation furnace charge drying device.

[0028] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0029] 1. Box body, 2. Drying tube, 21. Air outlet, 3. Circulation fan, 4. Electromagnetic heater, 5. Mesh belt conveyor, 6. Waste heat recovery pipe, 61. Air inlet, 7. Cyclone steam-water separator, 8. Slag collection plate, 9. Slag bucket, 10. Controller, 11. Feed hopper, 12. Discharge pipe, 13. Maintenance door, 14. Feeding conveyor, 15. Pressure reducing valve. DETAILED DESCRIPTION

[0030] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0031] like Figure 1 As shown, a closed hot air circulation furnace charge drying device comprises: a box 1, a drying mechanism, a conveying mechanism and a waste heat recovery mechanism.

[0032] A feed hole is provided on the top surface of the box body 1 and a discharge hole is provided on the lower side wall thereof. A feed hopper 11 is fixed and connected to the feed hole of the box body 1, and a discharge pipe 12 is fixed and connected to the discharge hole of the box body 1; the drying mechanism comprises a drying tube 2, a cyclone steam-water separator 7, a circulating fan 3 and an electromagnetic heater 4; the drying tube 2 is fixed on a fixed bracket in the box body 1 and a plurality of air outlets 21 are provided on the tube wall located in the box body 1; the circulating fan 3 is fixed to one end of the drying tube 2 extending out of the box body 1; the heating coil of the electromagnetic heater 4 is wound and fixed on the outer tube wall of the drying tube 2 extending out of the heating section of the box body 1; the conveying mechanism comprises a mesh belt conveyor 5, which is located in the box body 1 and corresponds to the plurality of air outlets 21 above Fixed on a fixed bracket in the box body 1, the feed end of the mesh belt conveyor 5 is connected with the discharge end of the feed hopper 11 and its discharge end is connected with the feed end of the discharge pipe 12; the waste heat recovery mechanism includes a waste heat recovery pipe 6 and a cyclone steam-water separator 7, the waste heat recovery pipe 6 is fixed on the fixed bracket of the box body 1 corresponding to the top of the mesh belt conveyor 5, and a plurality of air inlet holes 61 are provided on the pipe wall of the waste heat recovery pipe 6 extending into the box body 1; the cyclone steam-water separator 7 is fixed and connected to the end of the waste heat recovery pipe 6 extending out of the box body 1 and is connected to the circulating fan 3; the waste heat recovery pipe 6, the box body 1, the cyclone steam-water separator 7, the circulating fan 3 and the connecting pipe between the cyclone steam-water separator 7 and the circulating fan 3 are all provided with an outer layer of insulation.

[0033] Specifically, the box body 1 mainly includes a fixed bracket (made of carbon steel) and an internal sealing plate made of stainless steel, which is corrosion-resistant and has a long service life. The external sealing plates of the box body 1 are all made of carbon steel, which is low in cost. The inner sealing plate and the outer sealing plate are spaced 5-15 cm apart, and a 5-15 cm thick aluminum silicate plate is filled in the middle as an insulation layer. The preferred thickness of the utility model is 10 cm. The purpose is to prevent the waste heat in the box body 1 from being lost, to fully utilize the waste heat, and to achieve energy saving. The feed port, discharge port, waste heat recovery pipe, and air inlet and outlet of the high-temperature drying pipe of the box body 1 are reserved when they are made according to the actual required size, so that they can be well sealed after installation.

[0034] Specifically, the inner diameter of the heating section of the drying tube 2 is 20-40cm, preferably 30cm, the thickness of the heating section of the drying tube 2 is 1-5cm, preferably 3cm, and the outer layer of the heating section of the drying tube 2 is wrapped with A1 grade thermal insulation material, and is tied tightly with a high temperature resistant bandage to keep the thickness of the thermal insulation material at about 3cm. In order to make the installation more beautiful, a layer of 0.2-0.4cm insulating resin board, preferably 0.3cm, can be wrapped around the outer layer of the thermal insulation cotton. An electromagnetic induction coil is sleeved on the outer layer of the insulating resin board. The electromagnetic coil is provided with an insulating sleeve, which is mainly used for the protection of the electromagnetic coil. It is made of a glass fiber sleeve and covered with iron oxide red silica gel, which has the characteristics of high temperature resistance, thermal insulation, flame retardancy, electrical insulation, stable chemical properties, weather aging resistance, cold resistance, water resistance, oil resistance, corrosion resistance, ozone resistance, voltage resistance, arc resistance, corona resistance, etc., and the electromagnetic induction coil is made after being sleeved on the outside of a pure copper tube. The inter-turn gap of the induction coil should be as small as possible and the insulation should be good. The pure copper tube can be cooled by circulating water or filling with N2, preferably by water cooling in the tube. The electromagnetic induction coil made of the pure copper tube with an insulating sleeve is reliably wound on the outer layer of the heating section of the drying tube 2 of the insulating resin plate with a bracket. The electromagnetic coil made of the pure copper tube should be as smooth and tight as possible, and a double-layer coil is used for winding. After the coil is wound, the inductance of the coil is measured with an inductance meter to match the inductance and power indicators of the corresponding control cabinet. The output extension line of the induction coil is respectively connected to the high-frequency output terminal in the electromagnetic heater controller. Then, the outer layer of the coil made of the pure copper tube with an insulating sleeve is reliably wound with high-density glass fiber felt, and the outer layer is evenly coated with resin paint, which can play the role of thermal insulation and the skeleton of the electromagnetic heating coil for the electromagnetic coil made of the pure copper tube. The thickness of the high-density glass fiber felt is 10-30mm, preferably 20mm. High-density glass fiber felt can be continuously exposed to high temperatures within 1000°C without being damaged. In addition to preventing personnel from being burned by high-temperature pipelines, high-density glass fiber felt can also significantly reduce heat loss. After the above selection, the temperature of the outer surface of the heating section of the drying tube 2 does not exceed 45°C during operation. The electromagnetic heating coil has an operating frequency of 5 to 40kHz, and the operating temperature of the drying tube 2 wall of the heating section of the drying tube 2 is 850-950°C.

[0035] Specifically, each layer of drying tube 2 adopts Stainless steel pipe, with a bracket under the stainless steel pipe firmly supporting the corresponding mesh belt conveyor horizontally. A lot of 0.5-2cm air outlets are opened above each layer of stainless steel drying pipe 2 facing the mesh belt direction. The utility model preferably has 1cm air outlets, which can cover the corresponding entire upper mesh belt plane. When the equipment is running, the high-temperature dry air sprayed from the many small air outlets of the drying pipe 2 can cover the entire upper mesh belt, so that the high-temperature gas of the furnace charge on each layer of mesh belt is sprayed onto the furnace charge for uniform drying and preheating. The drying pipe 2 and the air outlets under each layer of mesh belt are basically maintenance-free.

[0036] Specifically, the electromagnetic heater 4 works on the principle of using alternating current to generate an alternating magnetic field. This alternating magnetic field generates eddy currents inside the metal conductor, thereby causing the metal workpiece to heat up rapidly. Generally speaking, the heating effect is jointly determined by frequency, current, and magnetic field. The electromagnetic heater 4 is composed of an electromagnetic induction heating controller and an electromagnetic heating coil, which is a heating system. Both are indispensable. The electromagnetic heating coil and the power controller induce eddy currents through the drying tube of the electromagnetic heating coil itself (this section of the drying tube with the electromagnetic heating coil is made of high carbon steel) to directly heat the tube wall of the drying tube 2 with the electromagnetic heating coil. The inner wall of the drying tube 2 directly transfers the heat energy to the self-circulating waste heat air in the drying tube 2. By heating the self-circulating waste heat air in the drying tube 2, the high-temperature and high-pressure air is evenly heated and transferred to the furnace charge, thereby improving the thermal efficiency of the electromagnetic heater, reducing the volume and manufacturing cost of the drying system, reducing the wind resistance coefficient in the entire waste heat recovery tube and the drying tube 2 loop, and reducing the active output of the circulating fan in the entire waste heat recovery pipeline loop; the electromagnetic induction controller is the control system of the electromagnetic heater.

[0037] Specifically, the cyclone steam-water separator 7 is a pressure vessel structure carbon steel or stainless steel device, and the utility model preferably uses stainless steel equipment. Under the action of the circulating fan 3, after the compressed air enters the cyclone steam-water separator 7 along the tangential direction of the inner wall of the cyclone steam-water separator 7 through the drying tube 2, it rotates inside by the tangential direction of the airflow, and the water droplets and dust particles mixed in the gas also rotate together and generate centrifugal force. The centrifugal force generated by the water droplets and dust particles with large mass is large. Under the action of centrifugal force, large water droplets and dust particles move toward the outer wall, and then gather and grow after hitting the outer wall (also the baffle) and separate from the gas. The separated liquid and dust particles fall into the lower part of the cyclone steam-water separator 7, and the liquid is discharged from the cyclone steam-water separator 7 through the steam trap; the dust particles fall into the bottom of the cyclone steam-water separator 7 and are regularly discharged from the dust storage bag at the bottom dust outlet; the dry and clean waste heat gas enters the circulating air duct from the air outlet of the cyclone steam-water separator 7 for reuse. The steam-water separation efficiency is high (the dryness of the hot circulating air can reach more than 98%), the pressure drop loss is small (about 0.1%), and the wind resistance is small; the design working temperature of the utility model is 550℃, the design negative pressure is ≥1.6MPa, the air inlet and air outlet diameters of the cyclone steam-water separator 7 are 300-500mm, preferably 400mm, and the air inlet, outlet and circulating air duct are flange-connected. The steam temperature entering the cyclone steam-water separator 7 is designed to be ≤450℃, and the speed entering the cyclone steam-water separator 7 is ≥13m / s, which can achieve a water removal and dust removal effect of more than 99%. Small size, light weight, easy installation, pipeline flange connection, can be suspended and installed, maintenance-free, and good reliability.

[0038] In some specific embodiments, there are multiple drying tubes 2, circulating fans 3, electromagnetic heaters 4, mesh belt conveyors 5 and waste heat recovery pipes. The multiple drying tubes 2 and the multiple mesh belt conveyors 5 are staggered and distributed along the height direction of the box body 1, and the discharge ends and feed ends of the mesh belt conveyors 5 adjacent to each other along the height direction of the box body 1 are connected, the feed end of the highest mesh belt conveyor 5 is connected to the discharge end of the feed hopper 11, and the discharge end of the lowest mesh belt conveyor 5 is connected to the feed end of the discharge pipe 12; the cyclone steam-water separator 7 is connected to the multiple circulating fans 3 through the waste heat recovery pipe.

[0039] In some specific embodiments, a debris collection mechanism may also be included, which includes a debris collection plate 8 and a debris bucket 9. The debris collection plate 8 is arranged below the mesh belt conveyor 5 and its edge bracket is fixed to the inner wall of the box body 1. The plate surface of the debris collection plate 8 is tilted downward from its edge to its center and a debris outlet hole is provided at the lowest point of its center; the debris bucket 9 is fixed to the debris outlet hole through a bracket.

[0040] In some specific embodiments, the slag collection mechanism further includes a slag discharger, which is fixed at the slag outlet of the slag bucket 9 through a flange;

[0041] In some specific embodiments, the slag collection mechanism further includes a slag arch breaker, which is fixed in the slag bucket and has a blowing port located between the slag outlet hole of the slag bucket 9 and the slag inlet hole of the slag discharger.

[0042] In some specific embodiments, the debris collection mechanism may further include a vibrator, which is fixed on the debris collection plate 8 .

[0043] In some specific embodiments, a humidity sensor, a temperature sensor and a controller 10 are also included. The humidity sensor, the temperature sensor and the controller 10 are all fixed on the box body 1, and the controller 10 is electrically connected to the circulating fan 3, the electromagnetic heater 4, the mesh belt conveyor 5, the cyclone steam-water separator 7, the humidity sensor and the temperature sensor respectively.

[0044] In some specific embodiments, a material level sensor is further included. The material level sensor is fixed in the feed hopper 11 . The material level sensor is fixed in the feed hopper 11 and is electrically connected to a feeding conveyor 14 that transports materials to the feed hopper 11 .

[0045] In some specific embodiments, the discharge pipe 12 is arranged to be inclined downward in a direction away from the mesh belt conveyor 5 .

[0046] In some specific embodiments, a maintenance door 13 is further included, and the side wall of the box body 1 is provided with an entry and exit hole; the maintenance door 13 is hinged at the entry and exit hole of the box body 1 and is provided with an observation hole, and a transparent glass is fixed at the observation hole.

[0047] In some specific embodiments, the box body 1 may also include an external support frame, on which the circulating fan 3, the electromagnetic heater 4 and the cyclone steam-water separator 7 are all fixed, and high-temperature resistant shock-proof pads are installed at all supporting points on the support frame.

[0048] In some specific embodiments, a pressure reducing valve 15 is installed between the cyclone steam-water separator 7 and the waste heat recovery pipe 6 .

[0049] In some specific embodiments, an online moisture meter is installed in the discharge pipe 12 .

[0050] In some specific embodiments, a pneumatic valve is installed at the discharge port of the discharge pipe 12 .

[0051] In some specific embodiments, the outer layer of the entire waste heat gas circulation loop of the waste heat recovery pipe 6, the cyclone steam-water separator 7, and the circulation fan 3 is treated with aluminum silicate insulation material.

[0052] The preferred embodiments of the present invention are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A closed hot air circulation furnace charge drying device, characterized in that: include: A box body (1), wherein a feed hole is provided on the top surface of the box body (1) and a discharge hole is provided on the lower side wall thereof, a feed hopper (11) is fixed and connected to the feed hole of the box body (1), and a discharge pipe (12) is fixed and connected to the discharge hole of the box body (1); A drying mechanism, the drying mechanism comprising a drying tube (2), a circulating fan (3) and an electromagnetic heater (4); the drying tube (2) is fixed on a fixed bracket in the box (1) and a plurality of air outlet holes (21) are provided on the tube wall located in the box (1); the circulating fan (3) is fixed on one end of the drying tube (2) extending out of the box (1); the heating coil of the electromagnetic heater (4) is wound and fixed on the outer tube wall of the heating section of the drying tube (2) extending out of the box (1); A conveying mechanism, the conveying mechanism comprising a mesh belt conveyor (5), the mesh belt conveyor (5) being located in the box body (1) and being fixed on a fixed bracket of the box body (1) above the corresponding plurality of air outlet holes (21), the feed end of the mesh belt conveyor (5) being connected to the discharge end of the feed hopper (11) and the discharge end thereof being connected to the feed end of the discharge pipe (12); A waste heat recovery mechanism, the waste heat recovery mechanism comprising a waste heat recovery pipe (6) and a cyclone type steam-water separator (7); the waste heat recovery pipe (6) is fixed on a fixed bracket of the housing (1) corresponding to the upper side of the mesh belt conveyor (5); a plurality of air inlet holes (61) are provided on the pipe wall of the waste heat recovery pipe (6) extending into the housing (1); the cyclone type steam-water separator (7) is fixed to and connected to one end of the waste heat recovery pipe (6) extending out of the housing (1) and connected to the circulating fan (3); the waste heat recovery pipe (6), the housing (1), the cyclone type steam-water separator (7), the circulating fan (3) and the connecting pipe between the cyclone type steam-water separator (7) and the circulating fan (3) are all provided with an outer layer of thermal insulation.

2. A closed hot air circulation furnace charge drying device according to claim 1, characterized in that: The drying tube (2), the circulating fan (3), the electromagnetic heater (4) and the mesh belt conveyor (5) are all multiple, and the multiple drying tubes (2) and the multiple mesh belt conveyors (5) are staggered and distributed along the height direction of the box body (1), and the discharge ends and feed ends of the mesh belt conveyors (5) adjacent to each other along the height direction of the box body (1) are connected, the feed end of the highest mesh belt conveyor (5) is connected to the discharge end of the feed hopper (11), and the discharge end of the lowest mesh belt conveyor (5) is connected to the feed end of the discharge pipe (12); the cyclone steam-water separator (7) is connected to the multiple circulating fans (3).

3. A closed hot air circulation furnace charge drying device according to claim 1, characterized in that: It also includes a debris collection mechanism, the debris collection mechanism including a debris collection plate (8) and a debris bucket (9), the debris collection plate (8) is arranged correspondingly below the mesh belt conveyor (5) and its edge is fixed on the inner wall of the box body (1), the plate surface of the debris collection plate (8) is arranged to be tilted downward from its edge to its center in sequence and a debris outlet hole is provided at the lowest point of its center; the debris bucket (9) is fixed at the debris outlet hole.

4. A closed hot air circulation furnace charge drying device according to claim 3, characterized in that: The slag collection mechanism also includes a slag discharger, which is fixed at the slag outlet of the slag bucket (9) through a flange; the slag collection mechanism also includes a slag arch breaker, which is fixed in the slag bucket and has a blowing port located between the slag outlet hole of the slag bucket (9) and the slag inlet hole of the slag discharger.

5. The closed hot air circulation furnace charge drying device according to claim 1, characterized in that: It also includes a humidity sensor, a temperature sensor and a controller (10), wherein the humidity sensor, the temperature sensor and the controller (10) are all fixed on the box body (1), and the controller (10) is electrically connected to the circulating fan (3), the electromagnetic heater (4), the mesh belt conveyor (5), the cyclone steam-water separator (7), the humidity sensor and the temperature sensor, respectively.

6. A closed hot air circulation furnace charge drying device according to claim 1, characterized in that: It also includes a material level sensor, which is fixed in the feed hopper (11) and is electrically connected to the feeding conveyor (14).

7. The closed hot air circulation furnace charge drying device according to claim 1, characterized in that: The discharge pipe (12) is arranged to be inclined downward in a direction away from the mesh belt conveyor (5).

8. The closed hot air circulation furnace charge drying device according to claim 1, characterized in that: It also comprises a maintenance door (13), and the side wall of the box body (1) is provided with an inlet and outlet hole; the maintenance door (13) is hinged at the inlet and outlet hole of the box body (1) and is provided with an observation hole, and transparent glass is fixed at the observation hole.

9. The closed hot air circulation furnace charge drying device according to claim 1, characterized in that: It also comprises a support frame, which is located outside the box body (1), and the circulating fan (3), the electromagnetic heater (4) and the cyclone steam-water separator (7) are all fixed on the external support frame.

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