WO2021223477A1

WO2021223477A1 - Continuous asphalt mixture stirring equipment

Info

Publication number: WO2021223477A1
Application number: PCT/CN2021/075423
Authority: WO
Inventors: 潘泽源; 王俊峰; 马昆斌
Original assignee: 福建省铁拓机械股份有限公司
Priority date: 2020-05-06
Filing date: 2021-02-05
Publication date: 2021-11-11
Also published as: CN212223526U

Abstract

Continuous asphalt mixture stirring equipment, comprising a virgin material conveying system (1), a regenerated material conveying system (2), a virgin material drying drum (3), a regenerated material drying drum (4), and a material mixing chute (5). The virgin material conveying system (1) is connected to the virgin material drying drum (3); the virgin material drying drum (3) comprises a virgin material feeding end (31) and a virgin material discharging end (32), the regenerated material drying drum (4) comprises a regenerated material feeding end (41) and a regenerated material discharging end (42); the material mixing chute (5) comprises a virgin material feeding port (51) connected to the virgin material discharging end (32), a regenerated material feeding port (52) connected to the regenerated material conveying system (2), and a discharging port (53) connected to the regenerated material feeding end (41); the regenerated material conveying system (2) conveys a regenerated material to the material mixing chute (5) to be mixed with a hot virgin material, and the mixed material enters the regenerated material drying drum (4) by means of the discharging port (53) to be mixed and heated. The production efficiency is improved, and the effect of steam and flue gas on the equipment, combustion, and environment is reduced.

Description

Continuous asphalt mixture mixing equipment

Technical field

The utility model relates to the field of asphalt production equipment, in particular to a continuous asphalt mixture mixing equipment.

Background technique

The existing asphalt mixture mixing equipment is divided into batch type and continuous type according to half of the mixing process. In the existing continuous technology, the main process flow is: 1. The virgin material is dried and heated through the inner drum through the double-layer drum, and then enters the outer drum, and the recycled material is simultaneously added to the outer drum and mixed together. , And finally the original recycled mixture is mixed together for a second time. The disadvantage of this method is that after the recycled cold material is mixed with the heated new aggregate, the asphalt on the surface of the recycled material has strong adhesion during the heating process, which can easily cause the outer drum to be blocked, causing the drum to fail and making the equipment impossible. Normal production; when the regeneration ratio is required to be high, the temperature of the recycled material can not meet the requirements of the final product temperature only by mixing with the primary hot aggregate in a short time. 2. Two sets of independent equipment, continuous primary equipment and continuous regeneration equipment, respectively carry out continuous drying and heating of virgin material and regenerated material. Continuous primary equipment includes: primary ingredient metering and conveying system, finished product warehouse, dust removal system; continuous regeneration equipment Including: Regenerative continuous batching metering and conveying system, regeneration hoist, regeneration drying system, hot material temporary storage bin, hot regenerated material continuous metering and conveying system, tail gas treatment system, regeneration additive system, regeneration pre-mixing system, regeneration cold addition Conveyor belt conveyor. This kind of technology has the disadvantages of occupying a large space, and the recycled material is easy to adhere to the inner wall of the drying drum during the drying and heating process.

Utility model content

The main purpose of the utility model is to overcome the shortcomings of the prior art and provide a continuous asphalt mixture mixing equipment that improves production efficiency and reduces equipment failure rate.

In order to achieve the above purpose, the technical solution adopted by the present utility model is as follows:

A continuous asphalt mixture mixing equipment includes a virgin material conveying system, a recycled material conveying system, a virgin drying drum, a regenerated drying drum, and a mixing chute. The virgin material conveying system is connected to the virgin drying drum, The virgin material is transported to the virgin drying drum for heating; the virgin drying drum includes a virgin feed end and a virgin discharge end; The material chute includes a raw material inlet connected to the original discharge end, a regeneration inlet connected to a recycled material conveying system, and a discharge outlet connected to the recycled material conveying system. The recycled material conveying system conveys the recycled material to In the mixing chute, together with the hot virgin material, it enters the regeneration drying drum from the discharge port for mixing and heating.

Further, the raw drying drum includes a first burner and a raw discharge box respectively arranged at the discharge end of the raw drying drum, and the first burner is used for supplying heat to the raw drying drum; The original feed inlet of the channel is connected with the original discharge box, so that the hot virgin material enters the mixing chute.

Further, the regenerative drying drum includes a hot blast furnace and a second burner connected to the hot blast furnace, the hot blast furnace is provided at the discharge end of the regenerative drying drum, and between the regenerative drying drum and the hot blast furnace There is a recycled output box.

Further, the raw material conveying system includes a raw material storage bin, a raw material metering component, a raw material feeding belt conveyor, and a raw material hoist. The raw material storage bin is used for storing raw material; the raw material measuring component is located Below the virgin cold storage bin, to measure and transport virgin materials to the virgin feeding belt conveyor; the virgin feeding belt conveyor is inclined upward toward the original hoist; the input end and the output end of the original hoist are respectively the same as the original feeding belt conveyor , Native drying drum connection.

Further, the recycled material conveying system includes a recycled cold silo, a recycled material metering assembly, a recycled feeding belt conveyor, and a recycling hoist. The recycled cold silo is used to store recycled materials; the recycled material metering assembly is located at Below the recycled cold storage bin to measure and transport recycled materials to the recycling feeding belt conveyor; the recycling feeding belt conveyor is inclined upward toward the regeneration hoist; the input end and the output end of the regeneration hoist are respectively connected to the regeneration feeding belt, The regeneration feed inlet of the mixing chute is connected.

Further, it also includes a continuous stirring device connected to the regeneration drying drum, a silo is provided below the continuous stirring device, the primary drying drum, the regeneration drying drum, the continuous stirring device, and the silo Arrange the settings in order from top to bottom.

Further, the continuous mixing device is connected to a powder conveying system, and the powder conveying system includes a powder silo, a powder transition scale, and a metering screw scale. The powder silo is used to store powder; the powder transition scale and the powder The silo is connected to measure the weight of the incoming powder; the metering screw scale is set under the powder transition scale to receive and measure the powder that enters the continuous mixing device.

Further, the continuous mixing device is connected to an asphalt conveying system, and the asphalt conveying system includes an asphalt silo, a first asphalt pump, an asphalt weighing scale, a second asphalt pump, and an asphalt flow meter arranged in sequence. An asphalt feed pipe is arranged between the input end of the metering scale, an asphalt discharge pipe is arranged between the output end of the asphalt metering scale and the continuous mixing device, and the asphalt flow meter is arranged on the asphalt discharge pipe.

Further, the silo includes a finished product silo, a finished waste silo, and a raw waste silo arranged in sequence, and a first three-way valve is provided between the continuous stirring device and the finished product silo and the finished waste silo for switching The conveying channel transports the finished material and the finished waste to the finished product silo and the finished waste silo; a second three-way valve is provided between the raw drying drum, the raw material conveying system and the raw waste silo to switch the conveying channel to The virgin material and the virgin waste are transported to the virgin drying drum and the virgin waste bin respectively.

Further, it also includes a dust removal device. The dust removal device includes a bag filter, a primary settling box, a secondary settling box, and a return air fan. The bag filter is arranged above the original drying drum. The feed end of the primary drying drum is connected to treat the waste gas generated by the primary drying drum; the primary settling box is located at the feed end of the regenerative drying drum, and a secondary settling box is connected between the primary settling box and the secondary settling box. A smoke pipe, a return air duct is connected between the secondary settling box and the regeneration drying drum, the return air fan is arranged on the return air duct; the first smoke pipe is connected to the discharge end of the original drying drum, and The first smoke pipe is provided with a first air regulating door; a second smoke pipe is connected between the first smoke pipe and the bag filter, and a second air regulating door is provided on the second smoke pipe.

From the above description of the utility model, it can be seen that compared with the prior art, the beneficial effects of the utility model are:

First, the heated virgin material and the regenerated material enter the regeneration drying drum at the same time, which can not only quickly heat and dry the regenerated material, but also ensure the drying efficiency and greatly extend the mixing time of the virgin material and the regenerated material. , Which makes the finished material more uniform, reduces the mixing time of the subsequent continuous mixing device, and the raw material enters the regeneration drying drum after heating, effectively reducing the adhesion of asphalt and recycled materials on the inner wall of the regeneration drying drum;

Second, when the proportion of recycled materials is high, the temperature of recycled materials can not meet the requirements of the final product temperature by only mixing the hot raw materials in a short time. Therefore, the regeneration drying drum 4 is equipped with a second The burner can make the temperature of the finished material meet the requirements;

Third, when the recycled materials are added and used, the recycled materials are mixed with the hot virgin materials in the mixing chute in advance, and the water vapor generated at the same time can be directly removed through the dust removal device to ensure the normal negative pressure of the equipment;

Fourth, by adopting a modular frame design, the equipment is compact, the smoke pipe is short, and the installation is convenient, which greatly reduces the occupation of the site and reduces the energy consumption.

Description of the drawings

Fig. 1 is a schematic diagram of the overall structure of a continuous asphalt mixture mixing equipment according to a specific embodiment of the present invention.

Fig. 2 is a partial schematic diagram of a continuous asphalt mixture mixing equipment according to a specific embodiment of the present invention.

Fig. 3 is a schematic diagram of the structure of a powder conveying system according to a specific embodiment of the present invention.

Fig. 4 is a schematic structural diagram of an asphalt conveying system according to a specific embodiment of the present invention.

In the picture: 1. virgin material conveying system, 11. virgin cold silo, 12. virgin material metering components, 121. virgin material belt scale, 122. virgin weighing sensor, 13. virgin feeding belt conveyor, 14. virgin lifting Machine, 15. Primary aggregate belt conveyor, 2. Recycled material conveying system, 21. Recycled cold storage bin, 22. Recycled material metering components, 221. Recycled material belt scale, 222. Recycled load cell, 23. Recycled feeding Belt conveyor, 24. Regenerative elevator, 25. Regenerative aggregate belt conveyor, 3. Original drying drum, 31. Original feed end, 32. Original discharge end, 33. First burner, 34. Original discharge Box, 4. Regenerative drying drum, 41. Regenerative feed end, 42. Regenerative discharge end, 43. Hot air furnace, 44. Second burner, 45. Regenerative discharge box, 5. Mixing chute, 51 .Native feed inlet, 52. Regenerative feed inlet, 53. Discharge port, 6. Continuous mixing device, 7. Powder conveying system, 71. Powder silo, 72. Powder transition scale, 73. Measuring screw scale , 74. Impeller feeder, 75. The first sensor, 76. The second sensor, 8. Asphalt conveying system, 81. Asphalt warehouse, 82. The first asphalt pump, 83. Asphalt metering scale, 84. The second asphalt pump , 85. Asphalt flow meter, 86. Asphalt feed pipe, 87. Asphalt discharge pipe, 9. Silo, 91. Finished product silo, 92. Finished waste silo, 93. Primary waste silo, 94. First tee Valve, 95. The second three-way valve, 0. Dust removal device, 01. Bag dust collector, 02. First-level settling tank, 03. Second-level settling tank, 04. Return air fan, 05. First smoke pipe, 06. Return air duct, 07. The first regulating damper, 08. The second smoke pipe, 09. The second regulating damper.

Detailed ways

The following further describes the utility model through specific implementations.

1 to 4, a continuous asphalt mixing equipment of the present invention includes a raw material conveying system 1, a recycled material conveying system 2, a raw drying drum 3, a recycled drying drum 4, and a mixing chute 5. Continuous mixing device 6, powder conveying system 7, asphalt conveying system 8, silo 9, dust removal device 0.

The virgin material conveying system 1 is connected to the virgin drying drum 3, and is used to transport the virgin material to the virgin drying drum 3 for heating; the virgin drying drum 3 includes a raw material feed end 31, a raw material discharge end 32, and a first burner 33. The original discharge box 34, the first burner 33, the original discharge box 34 are arranged at the original discharge end 32 of the original drying drum 3, and the first burner 33 is used for heating the original drying drum 3; The drying drum 4 includes a regeneration feed end 41, a regeneration discharge end 42, a hot blast furnace 43, and a second burner 44 connected to the hot blast furnace 43. The hot blast furnace 43 is provided at the regeneration discharge end 42, and the regeneration drying drum 4 is connected to the There is a regeneration discharge box 45 between the hot blast furnace 43, and the regeneration discharge box 45 is connected with the continuous mixing device 6, so that the raw material and the regenerated material can enter the continuous mixing device 6 for mixing and mixing; the mixing chute 5 includes The original feed port 51 connected to the material end 32, the regeneration feed port 52 connected to the recycled material conveying system 2, and the discharge port 53 connected to the recycled feed end 41. The recycled material conveying system 2 passes the recycled material through the regeneration feed The port 52 is conveyed into the mixing chute 5, the hot virgin material enters the mixing chute 5 from the virgin feed port 51, and the regenerated material and the hot virgin material enter the regeneration drying drum 4 through the discharge port 53 at the same time for mixing and heating.

The virgin material is heated by the virgin drying drum 3 and enters the regeneration drying drum 4 at the same time as the regenerated material, which can not only quickly heat and dry the regenerated material, but also ensure the drying efficiency and greatly extend the mixing of the virgin material and the regenerated material. Time makes the finished material more uniform and reduces the mixing time of the subsequent continuous stirring device 6; the raw material is heated and enters the regeneration drying drum 4, which effectively reduces the adhesion of asphalt and recycled materials on the inner wall of the regeneration drying drum 4; When the addition ratio is high, the temperature of the recycled material can not meet the requirements of the temperature of the final finished material by only mixing the hot raw material in a short time. Therefore, a second burner 44 is provided in the regeneration drying drum 4, which can make The temperature of the finished material meets the requirements; when the recycled material is added and used, the recycled material is mixed with the hot virgin material in the mixing chute 5 in advance, and the water vapor generated can be directly removed through the dust removal device 0 to ensure the normal negative pressure of the equipment.

The virgin material conveying system 1 includes a plurality of virgin cold silos 11, a plurality of virgin material metering components 12, a virgin feeding belt conveyor 13, a virgin hoist 14, and a plurality of virgin cold silos 11 are used to store raw materials of different gradations. The output end of each virgin cold silo 11 is equipped with a virgin aggregate belt conveyor 15, and each virgin cold silo 11 corresponds to each virgin material metering component 12 one-to-one, and the virgin material metering component 12 is arranged below the original cold silo 11 , The virgin material metering assembly 12 includes a virgin material belt scale 121 and a virgin weighing sensor 122 to measure and convey the virgin material to the virgin material feeding belt conveyor 13; the virgin material feeding belt conveyor 13 is inclined upward toward the original hoist 14; The input end and the output end of the machine 14 are respectively connected with the original feeding belt conveyor 13 and the original drying drum 3.

The recycled material conveying system 2 includes multiple recycled cold material bins 21, multiple recycled material metering components 22, recycled material feeding belt conveyor 23, and regeneration hoist 24. Multiple recycled cold material bins 21 are used to store different grades of regeneration. The output end of each recycled cold storage bin 21 is respectively provided with a recycled aggregate belt conveyor 25, each recycled cold storage bin 21 corresponds to each recycled material metering assembly 22, and the recycled material metering assembly 22 is arranged in the recycled cold storage bin 21 Below, the recycled material metering assembly 22 includes a recycled material belt scale 221 and a recycled weighing sensor 222 to measure and convey the recycled material to the recycled material feeding belt conveyor 23; the recycled material feeding belt conveyor 23 is inclined upward toward the regeneration hoist 24; The input end and output end of the hoist 24 are respectively connected with the regeneration feeding belt conveyor 23 and the regeneration feed inlet 52 of the mixing chute 5.

The powder conveying system 7 is connected with the continuous stirring device 6. The powder conveying system 7 includes a powder silo 71, a powder transition scale 72, a metering screw scale 73, an impeller feeder 74, and the powder silo 71 is used to store powder; The powder transition scale 72 is connected to the powder silo 71 to measure the weight of the incoming powder. The powder transition scale 72 is provided with a first sensor 75; the measuring screw scale 73 is set under the powder transition scale 72 to receive and measure For the powder entering the continuous mixing device 6, the measuring screw scale 73 is provided with a second sensor 76; the impeller feeder 74 is arranged between the powder transition scale 72 and the measuring screw scale 73.

The asphalt conveying system 8 is connected to the continuous mixing device 6. The asphalt conveying system 8 includes an asphalt silo 81, a first asphalt pump 82, an asphalt weighing scale 83, a second asphalt pump 84, an asphalt flow meter 85, and an asphalt silo 81 and asphalt. An asphalt feed pipe 86 is arranged between the input end of the metering scale 83, an asphalt discharge pipe 87 is arranged between the output section of the asphalt metering scale 83 and the continuous mixing device 6, and an asphalt flow meter 85 is arranged on the asphalt discharge pipe 87.

A silo 9 is provided below the continuous stirring device 6. The silo 9 includes a finished product silo 91, a finished waste silo 92, and a raw waste silo 93 arranged in sequence. The continuous stirring device 6 is arranged between the finished product silo 91 and the finished waste silo 91. There is a first three-way valve 94, which is used to switch the conveying channel to convey finished materials and finished waste materials to the finished product silo 91 and the finished waste silo 92; There is a second three-way valve 95 between them, which is used to switch the conveying channel to convey the virgin material and the virgin waste to the virgin drying drum 3 and the virgin waste bin 93 respectively.

Dust removal device 0 includes bag filter 01, primary settling box 02, secondary settling box 03, return air fan 04, bag filter 01 is set above the original drying drum 3, and bag filter 01 is connected to the original feed end 31 , Used to treat the waste gas generated by the original drying drum 3; the first settling box 02 is set at the regeneration feed end 41, a first smoke pipe 05 is connected between the first settling box 02 and the second settling box 03, and the second settling box A return air duct 06 is connected between the box 03 and the hot air furnace 43 of the regeneration drying drum 4, and the return air fan 04 is arranged on the return air duct 06; the first smoke pipe 05 is connected to the primary discharge end 32, and the first smoke The tube 05 is provided with a first regulating damper 07; a second smoke tube 08 is connected between the first smoke tube 05 and the bag filter 01, and the second smoke tube 08 is provided with a second regulating damper 09; the regeneration drying drum 4 Part of the exhaust gas generated sequentially passes through the first settling box 02, the first smoke pipe 05, the second settling box 03, the return air fan 04, and the return air duct 06, and enters the hot blast furnace 43 for secondary combustion; the regeneration drying drum 4 produces Part of the exhaust gas passes through the first smoke pipe 05 and enters the primary drying drum 3 for secondary combustion treatment, or passes through the first smoke pipe 05 and the second smoke pipe 08 in sequence, and is mixed with the exhaust gas generated by the primary drying drum 3 and then passes through The bag filter 01 is discharged after treatment.

The bag filter 01, the original drying drum 3, the regeneration drying drum 4, the continuous mixing device 6, and the silo 9 are arranged in order from top to bottom; the modular frame design makes the equipment compact, the smoke pipe is shorter, and the installation Convenient, greatly reducing the occupation of the site and reducing energy consumption.

The working principle of this kind of continuous asphalt mixing equipment is as follows:

When virgin material and recycled material are loaded, they are measured and fed through virgin material conveying system 1 and recycled material conveying system 2 respectively; virgin material is conveyed to virgin hoist 14 through virgin feeding belt conveyor 13, and virgin material passes through the second tee The valve 95 transports qualified raw materials to the raw drying drum 3 for heating and drying. The waste gas generated by the raw drying drum 3 enters the bag filter 01 for processing; the hot raw materials enter the mixing chute 5 from the raw drying drum 3, At the same time, the recycled material enters the mixing chute 5 through the regeneration hoist 24, and the recycled material and the hot virgin material enter the regeneration drying drum 4 from the mixing chute 5 at the same time, and the second burner 44 in the hot blast furnace 43 Burn, heat and dry the raw materials and regenerated materials in the regeneration drying drum 4; the hot raw materials and hot regenerated materials enter the continuous stirring device 6 through the regeneration discharge box 45, and the powder and The asphalt is mixed and agitated; the qualified finished materials after mixing enter the finished product silo 91 through the first three-way valve 94 for storage, and the finished waste materials enter the finished waste silo 92 through the first three-way valve 94.

The above is only a specific implementation of the utility model, but the design concept of the utility model is not limited to this. Any insubstantial modification of the utility model using this concept should be an act of infringement of the protection scope of the utility model. .

Claims

A continuous asphalt mixture mixing equipment, which is characterized in that it includes a virgin material conveying system, a recycled material conveying system, a virgin drying drum, a regenerated drying drum, and a mixing chute. The virgin material conveying system and the original drying The drum is connected to transport the virgin material to the virgin drying drum for heating; the virgin drying drum includes a virgin feeding end and a virgin discharging end, and the regeneration drying drum includes a regeneration feeding end and a regeneration discharging end , The mixing chute includes a raw material inlet connected to the raw material discharge end, a recycled material inlet connected to a recycled material conveying system, and a material outlet connected to the recycled material feeding end. The recycled material conveying system will The recycled materials are transported to the mixing chute, and together with the hot virgin materials, they enter the recycling drying drum from the discharge port for mixing and heating.
The continuous asphalt mixture mixing equipment according to claim 1, wherein the primary drying drum includes a first burner and a primary discharging box which are respectively arranged at the discharge end of the primary drying drum. The first burner is used to supply heat to the raw drying drum; the raw material inlet of the mixing chute is connected with the raw discharge box, so that the hot raw material enters the mixing chute.
The continuous asphalt mixing equipment according to claim 1, wherein the regeneration drying drum includes a hot air furnace and a second burner connected to the hot air furnace, and the hot air furnace is arranged in the regeneration drying furnace. At the discharging end of the drum, a regeneration discharging box is arranged between the regeneration drying drum and the hot air furnace.
The continuous asphalt mixing equipment according to claim 1, characterized in that: the raw material conveying system includes a raw cold silo, a raw material metering assembly, a raw material feeding belt conveyor, and a raw hoist. The virgin cold silo is used to store virgin materials; the virgin material metering component is arranged below the virgin cold silo to measure and transport the virgin materials to the virgin feeding belt conveyor; the virgin feeding belt conveyor is inclined upward toward the original hoist Setting; the input end and output end of the original hoist are respectively connected with the original feeding belt conveyor and the original drying drum.
The continuous asphalt mixing equipment according to claim 1, wherein the recycled material conveying system includes a recycled cold silo, a recycled material metering assembly, a recycled feeding belt conveyor, and a recycled hoist. The recycled cold storage bin is used to store recycled materials; the recycled material metering component is arranged below the recycled cold storage bin to measure and convey the recycled materials to the recycled feeding belt conveyor; the recycled feeding belt conveyor is inclined upward toward the regeneration hoist Setting: The input end and output end of the regeneration hoist are respectively connected with the regeneration feeding belt and the regeneration feed inlet of the mixing chute.
A continuous asphalt mixture mixing equipment according to claim 1, characterized in that it further comprises a continuous mixing device, the continuous mixing device is connected with the regeneration drying drum, and a silo is provided below the continuous mixing device, so The original drying drum, the regeneration drying drum, the continuous stirring device, and the silo are arranged in order from top to bottom.
The continuous asphalt mixture mixing equipment according to claim 6, characterized in that: the continuous mixing device is connected with a powder conveying system, and the powder conveying system includes a powder silo, a powder transition scale, and a metering system. Spiral scale, powder silo is used to store powder; powder transition scale is connected with powder silo to measure the weight of the incoming powder; metering screw scale is set under the powder transition scale to receive and measure the powder that enters the continuous mixing device.
The continuous asphalt mixture mixing equipment according to claim 6, characterized in that: the continuous mixing device is connected to an asphalt conveying system, and the asphalt conveying system includes an asphalt bin, a first asphalt pump, and an asphalt A metering scale, a second asphalt pump, and an asphalt flow meter. An asphalt feed pipe is arranged between the asphalt bin and the asphalt metering scale, and an asphalt discharge pipe is arranged between the asphalt metering scale and the continuous mixing device. The flow meter is set on the asphalt discharge pipe.
The continuous asphalt mixing equipment according to claim 6, wherein the silo comprises a finished product silo, a finished waste silo, and a raw waste silo arranged in sequence, the continuous mixing device and the finished product There is a first three-way valve between the warehouse and the finished product waste warehouse, which is used to switch the conveying channel to convey the finished material and the finished product waste to the finished product warehouse and the finished product waste warehouse respectively; the original drying drum, the original material conveying system and the original There is a second three-way valve between the waste bins, which is used to switch the conveying channel to transport the virgin material and the virgin waste to the virgin drying drum and the virgin waste bin respectively.
A continuous asphalt mixture mixing equipment according to claim 1, characterized in that it further comprises a dust removal device, the dust removal device includes a bag filter, a primary settling box, a secondary settling box, a return air fan, The bag filter is arranged above the original drying drum, and the bag filter is connected to the feed end of the original drying drum and is used to treat the waste gas generated by the original drying drum; the first-level settling box is arranged on the regeneration drying drum At the feed end, a first smoke pipe is connected between the first settling box and the second settling box, and a return air duct is connected between the second settling box and the regeneration drying drum, and the return air fan is arranged on the return air duct. The first smoke pipe is connected to the discharge end of the original drying drum, and the first smoke pipe is provided with a first regulating damper; a second smoke pipe is connected between the first smoke pipe and the bag filter, and the first smoke pipe is A second regulating damper is arranged on the second smoke pipe.