CN112284093A

CN112284093A - Drying device

Info

Publication number: CN112284093A
Application number: CN202011263790.4A
Authority: CN
Inventors: 孟国营; 庞志民; 刘双双; 赵旭; 张晓南; 翟宇; 胡兆春; 张义星; 吕向阳
Original assignee: Information Research Institute Of Emergency Management Department; Tianjin Boyle Technology Co ltd; Beijing Sinomine Sailibeite Energy Saving Science & Technology Co ltd
Current assignee: Information Research Institute Of Emergency Management Department; Tianjin Boyle Technology Co ltd; Beijing Sinomine Sailibeite Energy Saving Science & Technology Co ltd
Priority date: 2020-11-12
Filing date: 2020-11-12
Publication date: 2021-01-29

Abstract

The invention discloses a drying device, and relates to the technical field of wet coal slime drying. The drying device comprises a storage bin, a preheating mechanism, a drying mechanism and a waste heat recovery mechanism. The preheating mechanism comprises a first heat exchange assembly and a first storage bin, the first storage bin is communicated with the storage bin, and the first heat exchange assembly can heat materials in the first storage bin; the drying device comprises a drying bin and a heating assembly, wherein the drying bin is communicated with the first bin, and the heating assembly can heat the material in the drying bin; including air pipe and second heat exchange assembly, air pipe intercommunication dry storehouse, second heat exchange assembly get the end of heating and stretch into air pipe, second heat exchange assembly's the end of sending heat with first heat exchange assembly heat transfer is connected. This drying device can retrieve and preheat the coal slime to the waste heat behind the stoving coal slime, the energy saving.

Description

Drying device

Technical Field

The invention relates to the technical field of wet coal slime drying, in particular to a drying device.

Background

With the increasing awareness of society on low-carbon economy and energy conservation and emission reduction, coal slime is used as a byproduct of coal mining and processing, is difficult to realize industrial application due to the defects of high moisture, high viscosity, low calorific value and the like, is used as heating of people in coal mines and surrounding areas and is used as part of low-calorific-value industrial combustion, and not only is the heat energy utilization rate low, but also serious pollution is caused to the environment. Therefore, the inferior coal slime which has low grade, poor direct combustion rate and serious environmental pollution needs to be processed into high-quality clean energy, and the resource utilization rate is improved. The coal slime drying technology solves the problems of environmental pollution caused by long-term storage of coal slime in a coal preparation plant and incapability of disposing the coal slime after recovery, increases the economic benefit and social benefit of comprehensive utilization of coal products, realizes clean production and adapts to the requirements of the coal industry sustainable development strategy.

Because the coal slime humidity is very high, the temperature is very low, directly dries the coal slime, not only inefficiency and needs a large amount of heat energy for the coal slime stoving cost improves greatly. After the coal slime is dried, a large amount of generated hot air is directly discharged into the air, the temperature of the dried coal slime is high, and the coal slime needs to be cooled and then transported, so that a large amount of heat waste is caused.

To the above problems, a drying device needs to be developed to solve the problem that the waste heat after the coal slime is dried cannot be effectively recycled.

Disclosure of Invention

The invention aims to provide a drying device which can recover waste heat after coal slime drying and is used for preheating the coal slime, so that energy is saved.

In order to achieve the purpose, the invention adopts the following technical scheme:

a drying apparatus comprising:

a storage bin;

the preheating mechanism comprises a first heat exchange assembly and a first storage bin, the first storage bin is communicated with the storage bin, and the first heat exchange assembly can heat materials in the first storage bin;

the drying mechanism comprises a drying bin and a heating assembly, the drying bin is communicated with the first bin, and the heating assembly can heat the material in the drying bin;

waste heat recovery mechanism, including air pipe and second heat exchange assemblies, the air pipe intercommunication dry storehouse, the end of getting heat of second heat exchange assemblies stretches into air pipe, the end of sending heat of second heat exchange assemblies with first heat exchange assemblies heat transfer is connected.

Preferably, the second heat exchange assembly comprises a first heat pipe and a heat pump mechanism, the heat taking end of the first heat pipe extends into the ventilation pipeline, the heat taking end of the heat pump mechanism is in heat exchange connection with the heat releasing end of the first heat pipe, and the heat releasing end of the heat pump mechanism is in heat exchange connection with the first heat exchange assembly.

Preferably, the drying device further comprises a cooling mechanism, the cooling mechanism comprises a third heat exchange assembly and a second storage bin, the second storage bin is communicated with the drying bin, and the third heat exchange assembly is in heat exchange connection with a heat taking end of the heat pump mechanism.

Preferably, heating element includes second heat pipe and heating cabinet, the heating cabinet set up in the outside in dry storehouse, the end of giving out heat of second heat pipe stretches into dry storehouse, the end of getting heat of second heat pipe stretches into the heating cabinet.

Preferably, the heat radiating end of the second heat pipe is spiral, and the drying mechanism further comprises a driving assembly for driving the second heat pipe to rotate.

Preferably, the first bin, the second bin and the drying bin are externally coated with heat-insulating outer walls.

Preferably, the waste heat recovery mechanism further comprises a dust removal assembly, and the dust removal assembly is connected in series in the ventilation pipeline.

Preferably, the waste heat recovery mechanism still includes the draught fan, the draught fan set up in the dust removal subassembly with between the first heat pipe, the draught fan can with air current in the dry storehouse is introduced in the air pipe.

Preferably, preheat the mechanism and still include first transmission assembly, the relative both ends of first feed bin are provided with pan feeding mouth and discharge gate, the pan feeding mouth with storing feed bin intercommunication, the discharge gate with dry storehouse intercommunication, first transmission assembly can with the material by the pan feeding mouth carries extremely the discharge gate, first heat transfer assembly lays in first transmission assembly with between the first feed bin, and by the pan feeding mouth extends to the discharge gate.

Preferably, the first transmission assembly comprises a screw and a driving motor, and the screw is in transmission connection with an output shaft of the driving motor.

The invention has the beneficial effects that:

the invention provides a drying device. In the device, after the drying mechanism heats and dries the coal slime, hot air exchanges heat with the heat taking end of the second heat exchange assembly in the ventilation pipeline of the waste heat recovery mechanism, and heat is exhausted after being absorbed by the second heat exchange assembly. After the heat taking end of the second heat exchange assembly absorbs heat, the heat releasing end releases the heat to the first heat exchange assembly, and the first heat exchange assembly heats coal slime entering the preheating mechanism from the storage bin in the preheating mechanism, so that the utilization of drying waste heat is realized. Meanwhile, the coal slime is heated before entering the drying bin, so that the heat required in the drying bin is greatly reduced, and the energy is saved.

Drawings

FIG. 1 is a schematic structural diagram of a drying apparatus provided by the present invention;

fig. 2 is a schematic diagram of a heat pump mechanism according to the present invention.

1. A storage bin; 2. a preheating mechanism; 3. a drying mechanism; 4. a waste heat recovery mechanism; 5. a cooling mechanism; 6. a heat-insulating outer wall;

21. a first heat exchange assembly; 22. a first storage bin; 23. a first transmission assembly; 31. a drying bin; 32. a heating assembly; 33. a drive assembly; 41. a ventilation duct; 42. a second heat exchange assembly; 43. a bag-type dust collector; 44. an induced draft fan; 51. a third heat exchange assembly; 52. a second storage bin; 53. a second transmission assembly;

321. a second heat pipe; 322. a heating box; 421. a first heat pipe; 422. a heat pump mechanism; 4221. an evaporator; 4222. a compressor; 4223. a condenser; 4224. a throttle valve.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.

Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "secured" are to be construed broadly and encompass, for example, both fixed and removable connections; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may include the first feature being in direct contact with the second feature, or may include the first feature being in direct contact with the second feature but being in contact with the second feature by another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

The material in this embodiment is illustrated by taking coal slurry as an example.

The embodiment provides a drying device. As shown in fig. 1, the drying device includes a storage bin 1, a preheating mechanism 2, a drying mechanism 3, and a waste heat recovery mechanism 4. Preheating mechanism 2 includes first heat exchange assembly 21 and first feed bin 22, and first feed bin 22 intercommunication storing feed bin 1, the coal slime in first feed bin 22 can be heated to first heat exchange assembly 21. The drying mechanism 3 comprises a drying bin 31 and a heating assembly 32, the drying bin 31 is communicated with the first bin 22, and the heating assembly 32 can heat coal slime in the drying bin 31. The waste heat recovery mechanism 4 comprises a ventilation pipeline 41 and a second heat exchange assembly 42, the ventilation pipeline 41 is communicated with the drying bin 31, the heat taking end of the second heat exchange assembly 42 extends into the ventilation pipeline 41, and the heat releasing end of the second heat exchange assembly 42 is in heat exchange connection with the first heat exchange assembly 21.

The heating assembly 32 heats and dries the coal slime in the drying bin 31, the residual heat in the drying bin 31 is discharged through the air in the drying process, and the residual heat is discharged out of the drying device after being subjected to heat exchange with the heat taking end of the second heat exchange assembly 42 in the ventilation pipeline 41. The waste heat of the drying bin 31 is released to the first heat exchange assembly 21 through the heat release end of the second heat exchange assembly 42 to heat the first heat exchange assembly 21, the coal slime in the first storage bin 22 is preheated, and the utilization of the drying waste heat is realized.

Because the dried coal slime is still at a high temperature, if the dried coal slime is placed at will to be freely cooled to room temperature in the air, a large amount of heat can be wasted.

In order to effectively utilize the heat of the dried coal slurry, the drying device also comprises a cooling mechanism 5. The cooling mechanism 5 comprises a third heat exchange assembly 51 and a second storage bin 52, the second storage bin 52 is communicated with the drying bin 31, and the third heat exchange assembly 51 is in heat exchange connection with a heat taking end of the heat pump mechanism 422.

Wherein, the relative both ends of first feed bin 22 all are provided with pan feeding mouth and discharge gate, and pan feeding mouth and discharge gate set up for the horizontal direction of first feed bin 22, and the pan feeding mouth is on the upper portion of one end, and the discharge gate is in the lower part of the other end.

The discharge gate and the pan feeding mouth that the level set up can make the coal slime horizontal migration in first feed bin 22 and dry storehouse 31, and its speed is controllable, can guarantee going on fully of heat exchange.

In the same way, the drying bin 31 and the second bin 52 are both provided with a feeding port and a discharging port, and the set positions and reasons are the same as those of the first bin 22.

It can be understood that the feeding port of the first storage bin 22 is communicated with the storage bin 1, the discharging port of the first storage bin 22 is communicated with the feeding port of the drying bin 31, and the discharging port of the drying bin 31 is communicated with the feeding port of the second storage bin 52, so that a complete passage is formed.

Preferably, preheat mechanism 2 and still include first transmission assembly 23, first transmission assembly 23 can carry the coal slime to the discharge gate of preheating mechanism 2 by the pan feeding mouth of preheating mechanism 2, and first heat exchange assembly 21 lays between first transmission assembly 23 and first feed bin 22, and extends to the discharge gate of preheating mechanism 2 by the pan feeding mouth of preheating mechanism 2.

The coal slime is carried the discharge gate by the pan feeding mouth through first transmission assembly 23, can control the degree that the coal slime was preheated through the transmission speed of controlling first transmission assembly 23, and first heat exchange assembly 21 lays and to make the coal slime evenly preheat in first feed bin 22 between first transmission assembly 23 and first feed bin 22.

Preferably, the first transmission assembly 23 comprises a screw and a driving motor, and the screw is in transmission connection with an output shaft of the driving motor.

The driving motor drives the screw rod to rotate, the coal slime is stirred and crushed in the process of conveying the coal slime, preheating of the coal slime in the first storage bin 22 is sufficient, the crushing difficulty in the drying bin 31 is reduced, and the drying efficiency is improved.

It will be appreciated that the cooling mechanism 5 further comprises a second transmission assembly 53, which has the same structure as the first transmission assembly 23 and has the same effect, and will not be described in detail herein.

Further, the second heat exchange assembly 42 includes a first heat pipe 421, a heat taking end of the first heat pipe 421 extends into the ventilation duct 41, and a heat releasing end of the first heat pipe 421 is connected with the first heat exchange assembly 21 in a heat exchange manner.

The heat pipe has extremely fast heat conduction capability, the working medium in the heat pipe is gasified after absorbing heat at the heat taking end of the heat pipe and flows to the heat releasing end of the heat pipe, and a large amount of heat is released after liquefaction at the heat releasing end of the heat pipe. The first heat pipe 421 can greatly improve the recovery efficiency of the waste heat.

In order to further improve the utilization of the waste heat, the second heat exchange assembly 42 further comprises a heat pump mechanism 422, and a flowing circulating working medium is arranged in the heat pump mechanism 422. The heat taking end of the heat pump mechanism 422 is in heat exchange connection with the heat releasing end of the first heat pipe 421, and the heat releasing end of the heat pump mechanism 422 is in heat exchange connection with the first heat exchange assembly 21.

The heat release end of the first heat pipe 421 releases heat at the heat extraction end of the heat pump mechanism 422, the temperature rises after the heat is absorbed by the circulating working medium, the heat pump mechanism 422 applies work to the heat pipe, the temperature further rises, the heat is transferred to the first heat exchange assembly 21 through the heat release end, the coal slime is heated to a higher temperature in the first storage bin 22, and the output heat of the heating box 322 is further reduced.

Preferably, the heating assembly 32 includes a second heat pipe 321 and a heating box 322, the heating box 322 is disposed outside the drying chamber 31, a heat emitting end of the second heat pipe 321 extends into the drying chamber 31, and a heat taking end of the second heat pipe 321 extends into the heating box 322.

The heating box 322 heats and dries the coal slurry by heating the heat-taking end of the second heat pipe 321 to release the heat transferred to the heat-releasing end of the second heat pipe 321, and the heating box 322 may heat by combustion or by electricity, and in any method, when heating the coal slurry in the drying bin 31, a large amount of energy is consumed. And because the coal slime has been heated to certain temperature before entering drying storehouse 31, the heat that the messenger coal slime needs heating assembly 32 to provide when being dried in drying storehouse 31 reduces thereupon, can greatly reduced the consumption of the energy.

Further, a flowing first heat exchange medium is disposed in the first heat exchange assembly 21, and the first heat exchange medium flows through the heat release end of the first heat pipe 421 to exchange heat with the heat release end of the first heat pipe 421. The first heat exchange medium can be glycol solution, and the first heat exchange medium has the advantages of low specific heat capacity, and easy heating to high temperature, so that the temperature difference between the first heat exchange assembly 21 and the coal slime is increased, and the heat exchange is more sufficient. For cost reasons, water may also be chosen as the first heat exchange medium.

Preferably, a flowing second heat exchange medium is arranged in the third heat exchange assembly 51, the third heat exchange assembly 51 is used for cooling the high-temperature dried coal slime, and meanwhile, the absorbed heat is transferred to the heat taking end of the heat pump mechanism 422 through the second heat exchange medium, so that the waste heat is recycled, and the heat absorbed by the heat taking end of the heat pump mechanism 422 is further increased. The second heat exchange medium can be selected from water or glycol solution, and has the same reason as the first heat exchange medium, and is not described again here.

Further, as shown in fig. 2, the heat pump mechanism 422 further includes an evaporator 4221, a compressor 4222, a condenser 4223 and a throttle valve 4224, which are connected in sequence to form a circulating heat exchange loop. The compressor 4222 is used for compressing a circulating working medium in the circulating heat exchange loop, the evaporator 4221 is in heat exchange connection with the heat release end of the first heat pipe 421 and the third heat exchange assembly 51, the condenser 4223 is in heat exchange connection with the first heat exchange assembly 21, and the throttle valve 4224 is used for adjusting the flow of the circulating working medium. The circulating working medium can flow in the circulating heat exchange loop, can exchange heat with the second heat release end of the second heat pipe 321 and the second heat exchange assembly 42 in the evaporator 4221, and can exchange heat with the first heat exchange assembly 21 in the condenser 4223.

The circulating working medium absorbs heat of the heat release end of the first heat pipe 421 and the heat of the second heat exchange assembly 42 in the evaporator 4221 to evaporate, is compressed into high-temperature gas when flowing through the compressor 4222 and flows to the condenser 4223, heat is released in the condenser 4223 to heat the first heat exchange medium, and the high-temperature gas is liquefied and cooled to release a large amount of heat in the process, so that the temperature of the first heat exchange medium is ensured to be raised. Meanwhile, the throttle valve 4224 can be adjusted as required to control the flow of the circulating working medium, so that the temperature of the first heat exchange assembly 21 is reasonably controlled, and the energy is saved.

Wherein, the cycle fluid can be ammonia or freon.

The circulating working medium is characterized in that a substance which can be liquefied at normal temperature or lower temperature increases the heat change in a smaller temperature range through reversible phase change, thereby increasing the heat exchange efficiency.

Preferably, the throttle 4224 may be a capillary tube.

The circulating working medium condensed into liquid flows through the capillary tube, and the flow is limited because the circulating working medium enters the small tube from the large tube, so that the pressure of the discharged circulating working medium is reduced, the temperature is continuously reduced, the flow can be controlled, the temperature of the circulating working medium can be further reduced, and the heat exchange efficiency of the circulating working medium in the evaporator 4221 is improved.

Due to the fact that coal slime formed in production is stacked and is easily pasty or blocky, when the coal slime is dried in the drying bin 31, internal water cannot be evaporated in time, and the coal slime is not dried thoroughly, so that the coal slime needs to be scattered in the drying process.

Preferably, the heat radiating end of the second heat pipe 321 is arranged in a spiral shape, and the drying mechanism 3 further includes a driving assembly 33 for driving the second heat pipe 321 to rotate.

The second heat pipe 321 is driven by the driving component 33 to rotate, and the coal slurry entering the drying bin 31 is continuously stirred and crushed by the spiral structure in the heating and drying process, so that the coal slurry is fully dried.

Wherein, drive assembly 33 includes direct current motor and derailleur, and direct current motor's output shaft and second heat pipe 321 are connected to the derailleur, can control the rotational speed of second heat pipe 321 through the derailleur, and then control the broken degree of coal slime.

Further, the waste heat recovery mechanism 4 further includes a dust removal component connected in series in the path of the ventilation duct 41.

Moisture in the coal slurry is evaporated in the drying bin 31, and the hot and humid air in the drying bin 31 is discharged after heat exchange with the first heat pipe 421 through the ventilation duct 41. A large amount of fine dust generated during the drying process enters the ventilation duct 41 along with the hot and humid air and adheres to the surface of the first heat pipe 421, which seriously affects the absorption of the waste heat by the first heat pipe 421, and meanwhile, the dust is discharged into the air along with the hot and humid air, causing serious environmental pollution. Therefore, it is necessary to provide a dust removing unit in the path of the ventilation duct 41 so that the hot and humid air mixed with the dust is filtered by the dust removing unit in the ventilation duct 41.

Illustratively, the dust removal assembly may be a bag-type dust remover 43.

The bag-type dust collector 43 is a high-efficiency dry dust collector, and is a dust collector for collecting solid particles in dust-containing gas by using a bag-type filter element made of fiber weaved materials, and the action principle of the bag-type dust collector is that dust particles are intercepted due to the collision of inertial force and fibers when bypassing filter cloth fibers, so that the dust can be effectively filtered.

Preferably, the waste heat recovery mechanism 4 further includes an induced draft fan 44, and the induced draft fan 44 is disposed between the dust removal assembly and the first heat pipe 421, and is capable of introducing the airflow in the drying bin 31 into the ventilation duct 41.

The induced draft fan 44 can pump out the damp and hot air in the drying bin 31, promote the flow of the damp and hot air, and improve the recovery efficiency of the waste heat.

In order to further improve the heat exchange efficiency, the first heat exchange assembly 21 and the second heat exchange assembly 42 each include a plurality of heat exchange tubes through which the first heat exchange medium and the second heat exchange medium flow to exchange heat with the coal slurry.

It will be appreciated that the second transfer assembly 53 has the same structure as the first transfer assembly 23.

The coal slime through drying gets into second feed bin 52, and the coal slime temperature is higher this moment, and the screw rod in second feed bin 52 can once more stir, breakage the not broken coal slime in the rotatory in-process after drying, makes the cubic coal slime of complete drying not broken, reaches the dry condition under the effect of self temperature, and the coal slime of further breakage simultaneously is more abundant with second heat exchange component 42's heat exchange, is favorable to the recovery of waste heat.

Preferably, the first silo 22, the second silo 52 and the drying silo 31 are externally covered with the heat-insulating outer wall 6.

The heat preservation outer wall 6 can prevent waste heat from dissipating to the air through the silo wall to cause waste, and the waste heat is recycled to the maximum extent.

The above description is only a preferred embodiment of the present invention, and for those skilled in the art, the present invention should not be limited by the description of the present invention, which should be interpreted as a limitation.

Claims

1. A drying apparatus, comprising:

a storage bin (1);

the preheating mechanism (2) comprises a first heat exchange assembly (21) and a first storage bin (22), the first storage bin (22) is communicated with the storage bin (1), and the first heat exchange assembly (21) can heat materials in the first storage bin (22);

the drying mechanism (3) comprises a drying bin (31) and a heating assembly (32), the drying bin (31) is communicated with the first bin (22), and the heating assembly (32) can heat the materials in the drying bin (31);

waste heat recovery mechanism (4), including air pipe (41) and second heat exchange assemblies (42), air pipe (41) intercommunication dry storehouse (31), the end of getting heat of second heat exchange assemblies (42) stretches into air pipe (41), the end of sending heat of second heat exchange assemblies (42) with first heat exchange assemblies (21) heat transfer is connected.

2. The drying apparatus according to claim 1, wherein the second heat exchanging assembly (42) comprises a first heat pipe (421) and a heat pump mechanism (422), a heat taking end of the first heat pipe (421) extends into the ventilation duct (41), a heat taking end of the heat pump mechanism (422) is in heat exchanging connection with a heat releasing end of the first heat pipe (421), and a heat releasing end of the heat pump mechanism (422) is in heat exchanging connection with the first heat exchanging assembly (21).

3. The drying device according to claim 2, further comprising a cooling mechanism (5), wherein the cooling mechanism (5) comprises a third heat exchange assembly (51) and a second storage bin (52), the second storage bin (52) is communicated with the drying bin (31), and the third heat exchange assembly (51) is in heat exchange connection with a heat extraction end of the heat pump mechanism (422).

4. The drying device according to claim 1, wherein the heating assembly (32) comprises a second heat pipe (321) and a heating box (322), the heating box (322) is disposed outside the drying chamber (31), a heat emitting end of the second heat pipe (321) extends into the drying chamber (31), and a heat taking end of the second heat pipe (321) extends into the heating box (322).

5. The drying apparatus according to claim 4, wherein the heat releasing end of the second heat pipe (321) is spiral, and the drying mechanism (3) further comprises a driving assembly (33) for driving the second heat pipe (321) to rotate.

6. The drying device according to claim 3, characterized in that the first silo (22), the second silo (52) and the drying silo (31) are externally covered with a heat-insulating outer wall (6).

7. The drying device according to claim 2, characterized in that the waste heat recovery mechanism (4) further comprises a dust removal assembly, and the dust removal assembly is connected in series in the ventilation duct (41).

8. The drying device according to claim 7, characterized in that the waste heat recovery mechanism (4) further comprises an induced draft fan (44), the induced draft fan (44) is arranged between the dust removal assembly and the first heat pipe (421), and the induced draft fan (44) can introduce the airflow in the drying bin (31) into the ventilation duct (41).

9. The drying device according to claim 1, wherein the preheating mechanism (2) further comprises a first transmission assembly (23), opposite ends of the first bin (22) are provided with a feeding port and a discharging port, the feeding port is communicated with the storage bin (1), the discharging port is communicated with the drying bin (31), the first transmission assembly (23) can convey the material from the feeding port to the discharging port, and the first heat exchange assembly (21) is laid between the first transmission assembly (23) and the first bin (22) and extends from the feeding port to the discharging port.

10. Drying apparatus according to claim 9, wherein the first transmission assembly (23) comprises a screw and a drive motor, the screw being in driving connection with an output shaft of the drive motor.