Electromagnetic heating rotary kiln

Abstract

The invention relates to an electromagnetic heating rotary kiln which comprises a rotary kiln body provided with at least two heating areas which are arranged side by side in the axial direction of the kiln body. The heating units are arranged in the axial direction of the kiln at intervals, each heating unit corresponds to the corresponding heating area in a one-to-one mode, and when the kiln rotates, electromagnetic fields generated by the heating units in the working state completely cover the corresponding heating areas, so that the heating areas generate heat to heat materials located in the heating areas. According to the electromagnetic heating rotary kiln, at least two sets of heating units are arranged in the axial direction of the kiln at intervals, each set of heating unit corresponds to one heating area in a one-to-one mode, and the heating units are configured in the mode that when the kiln rotates, an electromagnetic field generated in the working state completely covers the corresponding heating areas; according to the kiln, the heating area generates heat to heat materials in the heating area, so that a heating dead area is avoided when the kiln rotates, the heating uniformity of the kiln is improved, and the materials can be fully heated.

Description

Technical Field

[0001] The invention relates to the field of rotary kilns, in particular to an electromagnetic heating rotary kiln. Background Art

[0002] The rotary kiln in the related art usually heats the material by internal burning, and uses flue gas with small specific heat capacity as the heating medium. The flue gas is usually high-temperature flue gas generated by the combustion of fuel (such as coal, natural gas, liquefied gas, water gas, etc.). The high-temperature flue gas can be sent into the rotary kiln through the blower. After the high-temperature flue gas and the material undergo radiation and convection heat exchange, it is forcibly discharged from the exhaust port, flue, exhaust gas treatment equipment and chimney through the induced draft fan. After the flue gas enters the kiln, the temperature gradient drops quickly, resulting in uneven heating of the material and insufficient heating (the high-temperature section in the kiln is short, and the material is subjected to high temperature for a short time), and the material heating temperature is uncontrollable, which ultimately leads to low product yield or low equipment output. In traditional externally heated rotary kilns (such as resistance rotary kilns), the surface of the rotary kiln is usually heated and then the heat is transferred to the inner surface of the rotary kiln and then heat exchanged with the material in the rotary kiln. The utilization rate of fuel is lower than that of internally fired rotary kilns. The resistance rotary kiln also has no directionality in its heat radiation and a large temperature difference between the inner and outer walls of the kiln shell, which causes heat transfer loss and slow heating speed. In addition, the higher the required temperature of the material, the slower the radiation heat transfer of the resistance rotary kiln, that is, the higher the temperature requirement, the lower the thermal efficiency. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an improved electromagnetic heating rotary kiln.

[0004] The technical solution adopted by the present invention to solve the technical problem is: construct an electromagnetic heating rotary kiln, comprising: A rotating kiln, the kiln having at least two heating zones, at least two of the heating zones being arranged side by side along the axial direction of the kiln; At least two groups of heating units are arranged at intervals along the axial direction of the kiln, each group of heating units is arranged in a one-to-one correspondence with each of the heating zones, and are configured to generate an electromagnetic field that completely covers the corresponding heating zone when the kiln rotates and is in a working state, so that the heating zone generates heat to heat the material located therein.

[0005] In some embodiments, when the kiln is not rotating, the projection of the heating unit on the side wall of the kiln covers a portion of the heating zone.

[0006] In some embodiments, each group of the heating units includes at least one group of induction coils, and the induction coils generate an electromagnetic field in a working state so that the heating zone actively heats the material in the heating zone.

[0007] In some embodiments, the induction coil is wound around the outer circumference of the kiln, and the radial direction of the induction coil forms a set angle with the axial direction of the kiln, and the set angle is greater than zero degree and less than forty-five degrees.

[0008] In some embodiments, the electromagnetic heating rotary kiln includes a driving assembly, and the driving assembly is connected to the heating unit to drive the heating unit to reciprocate in the axial direction of the kiln.

[0009] In some embodiments, the drive assembly includes a drive member and a slide plate; The driving member is connected to the slide plate to drive the slide plate to slide back and forth along the axial direction of the kiln; The slide plate extends along the axial direction of the kiln and is connected to each of the heating units to drive the heating units to reciprocate by sliding.

[0010] In some embodiments, each group of the heating units includes two groups of induction coils, which are arranged on two opposite sides of the kiln, and the projections of the two groups of induction coils on the side walls of the kiln do not completely overlap, so that when the kiln rotates and the heating units are in a working state, the electromagnetic field generated completely covers the corresponding heating zone.

[0011] In some embodiments, projections of two adjacent groups of the heating units on the side wall of the furnace do not completely overlap.

[0012] In some embodiments, the heating unit includes two fixing frames for fixing two groups of the induction coils, and the two fixing frames are arranged at two opposite sides of the kiln; Each set of induction coils is wound around a fixed frame facing one side of the kiln; The cross section of each fixing frame is arc-shaped.

[0013] In some embodiments, at least two temperature detection units are disposed on each of the heating units or each heating zone; And / or, each of the heating units is independently configured.

[0014] And / or, the electromagnetic heating rotary kiln further comprises a PLC control system connected to each of the heating units, the PLC control system comprises a DSP control module, and a human-computer interaction module connected to the DSP control module; The DSP control module is connected to the heating unit and the host computer, and is used to perform heating control on the heating unit and interact with the host computer; The human-computer interaction module is used to perform human-computer interaction operations and output and display data.

[0015] The electromagnetic heating rotary kiln of the present invention has the following beneficial effects: the electromagnetic heating rotary kiln is configured by arranging at least two groups of heating units at intervals in the axial direction of the rotatable kiln, and each group of heating units is arranged in a one-to-one correspondence with a heating zone. The heating units are configured to completely cover the corresponding heating zone with the electromagnetic field generated when the kiln rotates and is in a working state, so that the heating zone generates heat to heat the material located therein, so that no heating dead zone occurs when the kiln rotates, the uniformity of the kiln heating is improved, and the material can be fully heated, thereby improving the heat transfer efficiency, reducing the production cost, and being environmentally friendly and energy-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which: Figure 1 2 is a schematic structural diagram of an electromagnetic heating rotary kiln in a first embodiment of the present invention; Figure 2 yes Figure 1 The schematic diagram of the partial structure of the electromagnetic heating rotary kiln shown; Figure 3 yes Figure 1 A top view of the electromagnetically heated rotary kiln shown; Figure 4 yes Figure 1 A side view of an electromagnetically heated rotary kiln is shown; Figure 5 yes Figure 1 The schematic diagram of the PLC control system of the electromagnetic heating rotary kiln is shown; Figure 6 yes Figure 1 The schematic diagram of the intelligent operation interface of the PLC control system shown; Figure 7 yes Figure 1 The schematic diagram of the parameter detection interface of the PLC control system shown; Figure 8 is a schematic structural diagram of an electromagnetic heating rotary kiln in a second embodiment of the present invention; Fig. 9 yes Figure 8 A top view of the electromagnetically heated rotary kiln shown; Fig.10 yes Figure 8 The schematic diagram of the partial structure of the electromagnetic heating rotary kiln shown; Fig.11 yes Figure 8 A side view of an electromagnetically heated rotary kiln is shown; Fig.12 yes Figure 8 Another side view of the electromagnetic heated rotary kiln is shown. DETAILED DESCRIPTION

[0017] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "upper", "vertical", "lateral", "horizontal", "bottom", "inner", "outer", etc. are based on the directions or positional relationships shown in the accompanying drawings, are constructed and operated in a specific direction, and are only for the convenience of describing the technical solution, and do not indicate that the device or element referred to must have a specific direction, and therefore cannot be understood as a limitation to the present invention.

[0018] It should also be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be fixedly connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intermediate elements.

[0019] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0020] Figure 1 and Figure 2 The first embodiment of the electromagnetic heating rotary kiln of the present invention is shown. The electromagnetic heating rotary kiln can be used for low-temperature drying, medium-high temperature oxidation and reduction, high-temperature roasting, calcining and decomposition, etc. It can be widely used in new materials, petrochemicals, mineral processing and metallurgy, precious metal recycling, rare earth production, new energy and other industries. The electromagnetic heating rotary kiln is an intelligent production equipment that can be fully digitally controlled and automatically operated, with high efficiency, uniform and sufficient heating, and zero emissions, energy saving and environmental protection.

[0021] The electromagnetic heating rotary kiln utilizes the metal characteristics of the kiln and realizes the directional and efficient conversion of electromagnetic heat to the kiln through the electromagnetic heating principle. That is, heat is only generated directly on the kiln (closed-loop magnetic field, no dissipation), thereby achieving rapid heating of the material, avoiding the loss of heat non-directional radiation transfer and combustion exhaust emission in traditional heating methods, and ensuring rapid heating of equipment and materials.

[0022] The heating process does not require oxygen or other media, and the heating itself does not produce any emissions, which will not increase the amount of waste gas treatment of the material itself. The tail gas treatment volume is greatly reduced, and the tail gas treatment cost is tens or even hundreds of times less than that of the internal kiln. The electromagnetic heating rotary kiln production heating process is completely environmentally friendly.

[0023] The entire production heating process is safe and only requires conventional low-voltage electrical equipment protection. There are no destructive safety risks such as flammable and explosive materials, which greatly reduces safety investment.

[0024] like Figures 1 to 3 As shown, in this embodiment, the electromagnetic heating rotary kiln may include a frame 10. The frame 10 can be used to support various components and provide installation for various components. The frame 10 as a whole can be made of metal, such as stainless steel. In this embodiment, the frame 10 may include a support frame 11 and a support platform 12 arranged on the support frame 11. The support frame 11 can be a plurality of groups, and each group of support frames 11 can be arranged at intervals at the bottom of the support platform 12 along the length direction of the support platform 12. Each group of support frames 11 may include two support feet arranged at intervals along the width direction of the support platform 12. The support platform 12 can be arranged tilted. Generally, the height of the support frame 11 can be arranged in descending order along the length direction of the support platform 12, so that the support platform 12 is arranged tilted. In some other embodiments, the support platform 12 can also be arranged horizontally. That is, the height of each support frame 11 can be roughly the same. The support frame 11 and the support platform 12 can be connected and fixed by welding or setting a connecting component. In some embodiments, the connecting component can be selected as a screw connection component.

[0025] In this embodiment, the electromagnetic heating rotary kiln may include a kiln 20 that is rotatably arranged. The kiln 20 is a cylindrical structure with a hollow inner side, which can be installed on the support platform 12 and can be arranged longitudinally along the length direction of the support platform 12. The kiln 20 can be used for loading materials and providing a heating place for heating materials. In some embodiments, the kiln 20 can be provided with a feed port for feeding unheated materials and a discharge port for discharging heated materials. In some embodiments, the feed port and the discharge port can also be the same.

[0026] Generally, the kiln 20 can be made of carbon steel, heat-resistant steel, alloy steel, stainless steel (such as 304, 306, 316, 316L, 310S, etc.) or composite materials. The material can be determined according to the material properties and the temperature at which the material needs to be heated, and the manufacturing cost of the equipment can be fully saved after ensuring the durability of the equipment. The furnace wall of the kiln 20 can actively generate heat in the electromagnetic field to achieve rapid heating of the material in the kiln 20, avoiding the loss of heat transfer without direction and loss of combustion exhaust emissions in traditional heating methods, and ensuring rapid heating of the equipment and materials.

[0027] In this embodiment, the kiln 20 may be a small or medium-sized kiln with a diameter less than or equal to 1600 mm. In some other embodiments, the diameter of the kiln 20 may also be greater than 1600 mm, for example, the diameter of the kiln 20 may be greater than 2000 mm.

[0028] In this embodiment, the outer wall of the kiln 20 may be provided with an insulation structure, which can insulate the material inside the kiln 20, and it can also play a role of heat insulation to reduce the heat transfer to the outside. In some embodiments, the insulation structure can be an insulation sleeve, which can be sleeved on the outer periphery of the kiln 20. Of course, it can be understood that in some other embodiments, the insulation structure is not limited to the insulation sleeve, and it can be an insulation layer formed on the outer wall of the kiln 20 and integrally formed with the kiln 20. In some embodiments, the material of the insulation structure can be selected as a nano-scale insulation material, and the nano-scale insulation material can be obtained through existing technology.

[0029] Since the kiln 20 adopts electromagnetic heating, it can save refractory materials, thereby reducing a large amount of investment in refractory insulation, saving energy consumption for equipment heating, and the internal space of the kiln 20 of the same size is larger and the material loading capacity is larger. The kiln 20 generates heat directly, and the heating efficiency will not decay with the increase of temperature. That is, the higher the temperature requirement, the more obvious its energy efficiency advantage. Since the temperature difference between the inner and outer walls of the kiln 20 is small, its heat generation rate will not decay regardless of the temperature. The outer wall of the kiln 20 is in contact with the environment with nano-scale insulation materials, which is conducive to reducing the diameter of the kiln 20 with the same production capacity and reducing the area of ​​the outer surface, thereby reducing the heat transfer coefficient and heat dissipation area to the environment, making the heat loss (heat transfer coefficient*heat dissipation area*temperature difference) of the outer surface of the kiln 20 ten to dozens of times smaller than that of the internal firing kiln and the external heating rotary kiln.

[0030] In this embodiment, the kiln 20 has at least two heating zones 21, and the at least two heating zones 21 can be arranged side by side along the axial direction of the kiln 20. In some embodiments, the heating zones 21 can be formed by separating the kiln 20 by providing a partition plate. Of course, it can be understood that in some embodiments, the partition plate can be omitted. The heating zones 21 can be formed by heating the kiln in sections.

[0031] In this embodiment, each heating zone 21 can be independently set, and can independently heat the material in the corresponding heating zone 21, and can independently control the temperature. The heating zone 21 can accurately control the output energy in real time through a digital device, and can accurately provide heat according to the material heating temperature requirements and heating time so that the material in the heating zone 21 is accurately heated, heated at a constant temperature, and fully heated, thereby improving the material's yield or the adequacy of oxidation, reduction, decomposition, and calcination.

[0032] like Figure 3 and Figure 4As shown, in this embodiment, the electromagnetic heating rotary kiln further includes a rotating mechanism 30, which is mounted on the frame 10 and can be connected to the kiln 20 to drive the kiln 20 to rotate. The kiln 20 can rotate, so that the material in the kiln 20 can be heated evenly and fully.

[0033] In this embodiment, the rotating mechanism 30 may include a rotatable roller 31 and a transmission structure 32. There are two rollers 31, and the two rollers 31 may be arranged at both ends of the kiln 20. The two rollers 31 may be arranged to rotate synchronously. The transmission structure 32 may be arranged on the roller 31 and the kiln 20. Specifically, the transmission structure 32 may be a gear structure, which may include a first transmission gear and a second transmission gear. The first transmission gear may be arranged on the roller 31, and it may be an external gear. In some embodiments, the rotating mechanism 30 is not limited to the above structure, and the kiln 20 may be implemented using conventional technology.

[0034] For example Figures 1 to 3 As shown, in this embodiment, the electromagnetic heating rotary kiln may also include at least two groups of heating units 40, which may be arranged at intervals along the axial direction of the kiln 20, and each group of heating units 40 may be arranged in one-to-one correspondence with each heating zone 21. The heating unit 40 may be configured to completely cover the corresponding heating zone when the kiln 20 rotates and in a working state, so that the heating zone 21 generates heat to heat the material therein. The heating unit 40 can generate an electromagnetic field to actively heat the side wall of the kiln 20 where the corresponding heating zone 21 is located, thereby heating the material in the heating zone 21, thereby improving the heat transfer efficiency, and the heating process does not require other media, and there is no exhaust gas emission, so the cost of installing exhaust gas treatment equipment can be saved, and it is energy-saving and environmentally friendly. In addition, by providing at least two heating units 40 and configuring each heating unit 40 to completely cover the corresponding heating zone 21 with the electromagnetic field generated when the kiln rotates and is in a working state, the heating zone 21 generates heat to heat the material therein, so that no heating dead zone occurs when the kiln rotates, thereby improving the uniformity of the kiln heating and allowing the material to be fully heated.

[0035] In this embodiment, each group of heating units may include a fixed structure 41 and at least one group of induction coils 42, and the fixed structure 41 is used to fix the induction coils 42. In this embodiment, the induction coils 42 may be a group, which may generate an electromagnetic field in a working state so that the heating zone 21 actively heats the material in the heating zone 21. The material may contact the inner wall of the kiln 20 and be heated by the rotation of the kiln 20, which greatly saves the loss of heat energy in the transfer process and significantly improves the utilization rate of heat energy.

[0036] In this embodiment, the fixing structure 41 may include a plurality of fixing members 411, and each fixing member 411 may be arranged along the axial length of the induction coil 42. The plurality of fixing members 411 may be arranged at intervals along the circumference of the induction coil 42, and each fixing member 411 may be fixed to the outer surface of the induction coil 42. The plurality of fixing members 411 cooperate with each other to fix the induction coil 42 and to limit the position of the induction coil 42, so that the induction coil 42 can be kept tilted.

[0037] In this embodiment, when the kiln is not rotating, the projection of the heating unit 40 on the side wall of the kiln 20 can cover part of the heating zone 21. Specifically, the induction coil 42 can be wound around the outer circumference of the kiln 20, and the radial direction of the induction coil 42 can form a set angle with the axial direction of the kiln 20. The set angle can be greater than zero degrees and less than forty-five degrees, that is, each turn of the induction coil 42 can be tilted, so as to ensure that when the kiln 20 is rotating, the electromagnetic field generated by the induction coil 42 can completely cover the corresponding heating zone 21, thereby maximizing the heating area and heating efficiency, so that the kiln 20 will not have a heating dead zone, thereby improving the heating uniformity of the kiln 20, and allowing the material to be evenly and fully heated.

[0038] In this embodiment, each heating unit 40 can be independently set to achieve independent temperature control, and then one or more heating zones 21 can be selectively heated to prevent the material from being overheated or underheated in a certain heating zone, affecting product quality or being scrapped, and at the same time preventing the kiln 20 from being locally overheated and causing damage to the kiln 20.

[0039] In this embodiment, each heating unit 40 can reciprocate along the axial direction of the kiln 20. By reciprocating the heating unit 40 along the axial direction of the kiln 20. In this embodiment, the electromagnetic heating rotary kiln also includes a driving assembly 50, which can be connected to the heating unit 40 to drive the heating unit 40 to reciprocate in the axial direction of the kiln 20. The driving assembly 50 can drive the heating unit 40 to reciprocate within a set range, thereby avoiding the problem of uneven heating of the kiln 20 due to the uneven distribution of the magnetic moment structure inside the metal material, and ensuring that the magnetic field around the kiln 20 is evenly loaded to the kiln 20 and evenly heats.

[0040] In this embodiment, the driving assembly 50 may include a driving member 51, a slide plate 52, a pulley 53, a connecting bracket 54 and a connecting member 55. The driving member 51 may be connected to the slide plate 52, and may drive the slide plate 52 to slide on the support platform 12. In some embodiments, the driving member 51 may be an electric push rod, one end of which may be connected to one end of the slide plate 52, and the two may be connected and fixed by setting a connecting structure. The connecting structure may be a screw assembly or a clamping assembly. In some embodiments, the slide plate 52 may be extended along the axial direction of the kiln 20, and connected to each heating unit 40 to drive the heating unit 40 to reciprocate by sliding. The pulley 53 may be multiple groups, and the multiple groups of pulleys 53 may be arranged at intervals on the side of the slide plate 52 facing the support platform 12, and the slide plate 52 may slide under the drive of the driving member 51 and under the cooperation of the pulley 53. The connecting bracket 54 may be multiple, and the multiple connecting brackets 54 may be arranged at intervals along the length direction of the slide plate 52, and may be arranged one by one corresponding to the multiple heating units 40. Each connecting bracket 54 can be connected to the heating unit 40 by providing a connecting member 55. Specifically, the connecting member 55 can be a connecting rod, which can be connected to the fixed structure 41 of the heating unit 40.

[0041] In some other embodiments, the driving assembly 50 is not limited to an electric driving structure, and is not limited to the above-mentioned structure, but may also be other structures that push the heating unit 40 to repeatedly move in the axial direction of the kiln 20, such as a manual push rod, which can be connected to the fixed structure 41 of each heating unit 40.

[0042] In some embodiments, at least two temperature detection units 60 may be provided on each heating unit 40 or each heating zone 21. Specifically, in this embodiment, at least two temperature detection units 60 may be provided on each heating unit 40, and the at least two temperature detection units 60 may be provided at intervals along the axial direction of the induction coil 42. In this embodiment, there may be three temperature detection units 60 on each induction coil 42. By providing at least two temperature detection units 60 on each heating unit 40 or each heating zone 21, multi-point temperature measurement and temperature control can be achieved, so that it can be used to monitor the operating temperature of the kiln 20 during the production process, protect the highest point temperature rise, prevent local overheating of the kiln 20, and ensure that the material will not be over-roasted, and the durability of the kiln 20 will not be affected by overheating. In some embodiments, the temperature detection unit 60 can be a conventional temperature sensor.

[0043] In this embodiment, the design of heating by adopting multiple heating units 40 can be applied to various occasions, and through multi-point temperature measurement, for wet materials with high water content, the temperature control method of medium and low temperature dehumidification in the front stage and high temperature roasting in the back stage can be used to ensure maximum energy efficiency and avoid excessive heat loss due to drainage vapor.

[0044] like Figures 5 to 7 As shown, in this embodiment, the electromagnetic heating rotary kiln also includes a PLC control system, which can be connected to each heating unit 40, so that each heating unit 40 can be independently temperature controlled, so that the material in each heating zone 21 can be independently heated. In some embodiments, the PLC control system can also be connected to the temperature detection unit 60, and the temperature information detected by the temperature detection unit 60 can be fed back to the PLC control system, and the PLC control system can control the heating unit 40 according to the temperature information.

[0045] Furthermore, in this embodiment, the PLC control system includes a DSP control module and a human-computer interaction module connected to the DSP control module; wherein the DSP control module can be connected to the heating unit 40 and the host computer to perform heating control on the heating unit 40 and interact with the host computer. In some embodiments, the DSP control module can timely and accurately communicate with the host computer by wire or wireless communication, realize digital Internet of Things and unattended production, and reduce production labor costs. The human-computer interaction module can be used to perform human-computer interaction operations and output data for display.

[0046] In this embodiment, the intelligent operation interface of the PLC control system can be as follows: Figure 6 As shown, its parameter detection interface can be Figure 8 As shown. The PLC control system utilizes the digital control technology of the DSP embedded system and the flexible setting characteristics of the induction coil 42 to drive the control system to evenly distribute the magnetic field, and can design the heating zone 21 according to the user's process requirements to achieve automatic uniform heating, ensure real-time temperature monitoring and adjustment, so that the heat energy is fully and evenly used to the greatest extent, and further improve the quality and production capacity of the material. Relying on the embedded advantages of the PLC control system, all production data are realized on the data platform, and the data is connected to the Internet of Things platform for remote monitoring and operation, and it has precise control and real-time communication functions to achieve unattended production.

[0047] Generally, based on on-site operating habits, the traditional production control interface is designed to be intelligent and fool-proof to ensure that the temperature, range, energy consumption and production process of the entire heating process are controllable, thereby realizing the intelligent upgrade of the system.

[0048] Figures 8 to 12The second embodiment of the electromagnetic heating rotary kiln of the present invention is shown. The difference between the second embodiment and the first embodiment is that the kiln 20 can be a large kiln with a diameter greater than 2000 mm. The projections of the two adjacent groups of heating units 40 on the side wall of the kiln 20 do not completely overlap, that is, the projections of the two adjacent groups of heating units 40 on the side wall of the kiln 20 can be partially overlapped or completely non-overlapped, thereby defining a plurality of heating zones 21, so that the materials in each heating zone 21 can be heated. Each group of heating units 40 can include two groups of induction coils 42, which can be arranged on two opposite sides of the kiln 20, and the projections of the two groups of induction coils on the side wall of the kiln 20 do not completely overlap, so that when the kiln 20 rotates and the heating units 40 are in the working state, the electromagnetic field generated completely covers the corresponding heating zone 21. Specifically, the two groups of induction coils 42 of each group of heating units 40 can be on both sides of the kiln 20 in the transverse direction and located at the bottom of the kiln 20. The induction coils 42 on both sides of the kiln 20 in the transverse direction can be staggered. That is, the two groups of induction coils 42 of each heating unit 40 are staggered on both sides of the heating area 21, so as to ensure that the kiln 20 can reduce the magnetic field coupling interference between the induction coils 42, and increase the heating area of ​​the kiln 20, and ensure that there is no area that cannot be covered by the magnetic field in the kiln 20. By arranging the induction coils 42 on each side at equal distances, it is ensured that the materials in the kiln 20 can be heated evenly to the greatest extent, and the product will not be wasted due to insufficient or over-burning of the materials.

[0049] In this embodiment, the fixing structure 41 of each heating unit 40 may include two fixing frames 412 for fixing the two sets of induction coils 42, and the two fixing frames 412 may be arranged at two opposite sides of the kiln 20. Specifically, each fixing frame 412 may cover a part of the outer periphery of the kiln 20 and be located on a side of the kiln 20 facing the support platform 12. In this embodiment, the cross section of each fixing frame 412 may be roughly arc-shaped, that is, the fixing frame 412 may be roughly tile-shaped. Each set of induction coils 42 may be coiled and arranged on a side of the fixing frame 412 facing the kiln 20. The shape of each set of induction coils 42 may be adapted to the shape of the fixing frame 412.

[0050] The electromagnetic heating rotary kiln of the present invention has the following advantages: 1. Traditional rotary kilns need to use fuel combustion, which requires sufficient oxygen (the oxygen content in the air is only about 21%). The exhaust gases such as carbon oxides, nitrogen oxides, and sulfur dioxide produced by combustion will cause partial air pollution and a large amount of carbon emissions even after exhaust gas treatment. If the material itself produces toxic exhaust gas, the flue gas after heat exchange and more than 78% of nitrogen in the air will be mixed with the material exhaust gas, resulting in a huge exhaust gas treatment volume and high treatment costs. In addition, during the production process of the internally fired rotary kiln, due to the high temperature of the flue gas entering the kiln and sufficient air supply and oxygen supply, the mixing ratio of the flue gas produced by combustion and the material dust will exceed the explosion limit and form explosion conditions if the operation is improper, thus bringing huge safety hazards. In addition, the radiation heat conversion efficiency of the heat source of the internally fired rotary kiln is low, and the huge amount of refractory materials such as refractory bricks in the lining will absorb a lot of heat, resulting in slow heating of the equipment and low effective utilization of energy. If the rotary kiln is heated outside the drum, the exhaust gas temperature will be higher and the thermal utilization rate will be lower. Due to the low utilization rate, the energy cost of producing a ton of products in the traditional rotary kiln is high. The higher the temperature requirement, the lower the heat utilization rate. The present application adopts the principle of electromagnetic induction to enable the kiln 20 made of weakly magnetic high-temperature resistant stainless steel to actively heat the materials therein, replacing the traditional open flame blowing and resistance heating methods. The roasting is sufficient, the thermal efficiency is high, the durability is good, and the safety is high. The durability of the equipment is greatly improved compared with the traditional rotary kiln, and the cost of tail gas treatment can be saved.

[0051] 2. For small and medium-sized kilns, by setting the induction coil 42 in an inclined manner and reciprocating operation, and performing zone heating control according to process requirements, the kiln 20 is ensured to be fully heated and the temperature is uniform, and is controlled and adjustable in real time, so that the material can be fully heated automatically, uniformly, quickly and fully, greatly improving the product quality. For example, when used to calcine low-grade lean iron ore, iron ore powder with a grade of more than 60 can be obtained, which will make full use of my country's abundant reserves of limonite and siderite.

[0052] 3. For large kilns, the arc-shaped staggered induction coils 42 are arranged on the bottom surface of the kiln 20, so that the kiln 20 is fully and completely covered by the magnetic field during the rotation process, ensuring that the kiln 20 is fully heated and the materials are evenly heated. With the reciprocating operation setting, it can avoid the furnace body from being damaged by local overheating due to uneven internal magnetic moment. The life of large kilns is greatly improved.

[0053] 4. Use DSP embedded PLC control system to replace ordinary electric heating and traditional fuel heating systems. Relying on the precise control and real-time communication functions of the digital system, timely and accurate wired or wireless communication connection with the host computer is carried out to realize the digital Internet of Things and unattended production of traditional equipment, thus reducing production labor costs.

[0054] It can be understood that the above embodiments only express the preferred implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the patent scope of the present invention. It should be pointed out that, for ordinary technicians in this field, the above technical features can be freely combined without departing from the concept of the present invention, and several deformations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should belong to the coverage of the claims of the present invention.

Claims

1. An electromagnetic heating rotary kiln, characterized in that: include: A rotatably arranged kiln (20), the kiln (20) having at least two heating zones (21), the at least two heating zones (21) being arranged side by side along the axial direction of the kiln (20); At least two groups of heating units (40) are arranged at intervals along the axial direction of the kiln (20), and each group of heating units (40) is arranged in a one-to-one correspondence with each heating zone (21), and are configured to completely cover the corresponding heating zone (21) with the electromagnetic field generated when the kiln (20) rotates and is in a working state, so that the heating zone (21) generates heat to heat the material located therein.

2. The electromagnetic heating rotary kiln according to claim 1, characterized in that: When the kiln (20) is not rotating, the projection of the heating unit (40) on the side wall of the kiln (20) covers a portion of the heating area (21).

3. The electromagnetic heating rotary kiln according to claim 1, characterized in that: Each group of the heating units (40) comprises at least one group of induction coils (42), and the induction coils (42) generate an electromagnetic field in a working state so that the heating zone (21) actively heats the material in the heating zone (21).

4. The electromagnetic heating rotary kiln according to claim 3, characterized in that: The induction coil (42) is wound around the outer circumference of the kiln (20), and the radial direction of the induction coil (42) forms a set angle with the axial direction of the kiln (20), and the set angle is greater than zero degrees and less than forty-five degrees.

5. The electromagnetic heating rotary kiln according to claim 3, characterized in that: The electromagnetic heating rotary kiln comprises a driving assembly (50), wherein the driving assembly (50) is connected to the heating unit (40) to drive the heating unit (40) to reciprocate in the axial direction of the kiln (20).

6. The electromagnetic heating rotary kiln according to claim 5, characterized in that: The driving assembly comprises a driving member (51) and a sliding plate (52); The driving member (51) is connected to the slide plate (52) to drive the slide plate (52) to slide back and forth along the axial direction of the kiln (20); The slide plate (52) extends along the axial direction of the kiln (20) and is connected to each of the heating units (40) so as to drive the heating unit (40) to reciprocate by sliding.

7. The electromagnetic heating rotary kiln according to claim 1, characterized in that: Each group of the heating units (40) includes two groups of induction coils (42), and the two groups of induction coils (42) are arranged on two opposite sides of the kiln (20), and the projections of the two groups of induction coils (42) on the side wall of the kiln (20) do not completely overlap, so that when the kiln (20) rotates and the heating units (40) are in a working state, the electromagnetic field generated completely covers the corresponding heating area (21).

8. The electromagnetic heating rotary kiln according to claim 7, characterized in that: The projections of two adjacent groups of the heating units (40) on the side wall of the kiln (20) do not completely overlap.

9. The electromagnetic heating rotary kiln according to claim 7, characterized in that: The heating unit (40) comprises two fixing frames (412) for fixing two groups of the induction coils (42), and the two fixing frames (412) are arranged on two opposite sides of the kiln (20); Each group of induction coils (42) is wound around a fixing frame (412) facing one side of the kiln (20); The cross section of each fixing frame (412) is arc-shaped.

10. The electromagnetic heating rotary kiln according to claim 1, characterized in that: Each of the heating units (40) or each of the heating zones (21) is provided with at least two temperature detection units; And / or, each of the heating units (40) is independently provided; And / or, the electromagnetic heating rotary kiln further comprises a PLC control system connected to each of the heating units (40), the PLC control system comprising a DSP control module and a human-computer interaction module connected to the DSP control module; The DSP control module is connected to the heating unit (40) and the host computer, and is used to execute heating control on the heating unit (40) and interact with the host computer; The human-computer interaction module is used to perform human-computer interaction operations and output and display data.

Images