An automated production line and preparation process for preparing biomass fuel using waste wood

Abstract

The present invention discloses an automated production line and preparation process for preparing biomass fuel using waste wood, including a crushing system, a conveying system and a pelletizer. The crushing system includes a hammer crusher, a wood block bin, and a blade crusher. The feed port of the hammer crusher is connected to the feed conveyor, the discharge port is connected to the discharge conveyor, the discharge conveyor is connected to the wood block bin, and the discharge conveyor is provided with an iron removal device; the lower part of the wood block bin is used to convey materials to the blade crusher in turn through multiple first screw conveyors; an isolation room is provided on the outer side of the hammer crusher, and the upper part of the isolation room is connected to the first dust collector through a negative pressure air duct; the conveying system includes a negative pressure conveying pipe, a cyclone separator, a wood chip powder bin and a second dust collector, and the conveying system sends the wood chip powder from the discharge port of the blade crusher to the pelletizer for extrusion and pelletization. The present invention has a high degree of automation, can ensure the stable quality of the prepared biomass fuel, and make the workplace meet the requirements of environmental protection, health and safety.

Description

Technical Field

[0001] The invention relates to the technical field of manufacturing equipment for processing waste wood, and in particular to an automated production line and a preparation process for preparing biomass fuel using waste wood. Background Art

[0002] With the advancement of urbanization, a large amount of waste wood will be generated during the renovation and demolition of cities. These waste wood will either be landfilled, occupying a large amount of land, or burned directly. However, the calorific value generated by direct combustion is not high, and it will pollute the atmosphere. Therefore, people began to study how to process these waste wood. At present, the more feasible way is to crush these waste wood and then compress and granulate them into biomass fuel, forming an environmentally friendly fuel with a higher calorific value. It not only provides environmentally friendly fuel for various small and medium-sized boilers, but also reduces dust emissions. It is a good solution for resource and environmental protection utilization.

[0003] However, to make biomass fuel from recycled waste wood, it must go through at least three steps: crushing the waste wood into sawdust powder, conveying the sawdust powder, and extruding and pelletizing the sawdust powder. Since the composition of recycled waste wood is relatively complex, it usually includes various logs, artificial plywood, artificial fiberboard, decorative strips, nails, screws, handles and various nails for nail guns, etc. There are three main problems in the process from crushing to pelletizing:

[0004] First, there are environmental and safety issues in the workplace. The crushing process of waste wood produces loud noise and serious dust pollution, which poses environmental, health, safety and explosion-proof issues.

[0005] The second is the recycling of waste wood from daily life. Since the moisture content and fiber length of waste wood recycled from different batches, different locations and different seasons are different, the quality of the sawdust powder formed after crushing is unstable, resulting in unstable quality of the biomass fuel formed by pelletizing.

[0006] Third, due to the complex composition of recycled waste wood, the presence of some metals in the crushing stage can easily damage the crusher blades; in the extrusion granulation stage, the presence of larger metals can easily cause the compression mold to crack and explode, which will affect the normal operation of the entire production, reduce output, and increase the manufacturing cost of biomass fuel.

[0007] Among the existing waste wood processing equipment, there is no production equipment that can better handle the above three problems. Therefore, this case is proposed. Summary of the invention

[0008] The technical problem to be solved by the present invention is to provide an automated production line for preparing biomass fuel using waste wood, which has a high degree of automation, can ensure the stable quality of the prepared biomass fuel, and make the workplace meet the requirements of environmental protection, health, safety and explosion prevention.

[0009] To achieve the above-mentioned purpose, the technical scheme of the present invention is: an automated production line for preparing biomass fuel using waste wood, including a crushing system, a conveying system and a pelletizer, the crushing system includes a hammer crusher and a blade crusher, the feed port of the hammer crusher is connected to the feed conveyor, the discharge port of the hammer crusher is connected to the discharge conveyor, the output end of the discharge conveyor is connected to the upper part of a wood block bin, and the discharge conveyor is provided with an iron removal device; a plurality of first screw conveyors are installed at the lower part of the wood block bin, the feed end of each first screw conveyor is connected to the internal space of the wood block bin, the discharge end of each first screw conveyor is connected to the feed port of the blade crusher, and the plurality of first screw conveyors act in turn to convey materials;

[0010] An isolation room is provided outside the hammer mill, and the isolation room covers part of the feed conveyor and the discharge conveyor. The upper part of the isolation room is connected to the first dust collector through a negative pressure air duct, and a first fan is installed in the middle of the negative pressure air duct, and the first fan generates negative pressure in the isolation room;

[0011] The conveying system includes a negative pressure conveying pipe, a cyclone separator and a second dust collector. One end of the negative pressure conveying pipe is connected to the discharge port of the blade crusher, and the other end of the negative pressure conveying pipe is connected to the gas inlet on the side of the cyclone separator. The upper gas outlet of the cyclone separator is connected to the air suction port of the second fan, and the air outlet of the second fan is connected to the second dust collector through a pipeline; the lower discharge port of the cyclone separator is connected to the feed end of the second screw conveyor through an air lock, and the wood chip powder sent out from the discharge end of the second screw conveyor is extruded and granulated by a granulator.

[0012] Further improvement, the conveying system also includes a sawdust powder bin, the discharge end of the second screw conveyor is connected to the upper part of the sawdust powder bin; the lower part of the sawdust powder bin is equipped with a third screw conveyor, the feed end of the third screw conveyor is connected to the internal space of the sawdust powder bin, and the discharge end of the third screw conveyor is connected to the feed port of the pelletizer;

[0013] The dust removal port of the second dust collector is connected to the air suction port of the third fan through a pipeline, and the air outlet of the third fan is connected to the upper part of the sawdust powder bin through a pipeline; the sawdust powder bin is equipped with a stirring tool driven by a motor.

[0014] In this way, through the setting of the sawdust powder bin, after the sawdust powder enters the cyclone separator, most of the coarse sawdust powder will fall into the lower part of the cyclone separator, and then be sent to the sawdust powder bin through the first screw conveyor; some fine sawdust powder is captured by the second dust collector through the pipeline through the upper gas outlet of the cyclone separator, and after the second dust collector is cleaned, these fine sawdust powders are also sent to the sawdust powder bin through the third fan and pipeline. In the sawdust powder bin, the coarse sawdust powder and the fine sawdust powder are mixed by the stirring tool to form sawdust powder with stable quality, and these sawdust powders are then sent to the pelletizer for pelletizing through the third screw conveyor. On the one hand, the crushed sawdust powder can be better utilized, the loss of sawdust powder can be reduced, and the quality of the sawdust powder can be further ensured.

[0015] Furthermore, a plurality of third screw conveyors are installed at the lower part of the sawdust powder bin, and the discharge end of each third screw conveyor is connected to the feed port of a pelletizer, so as to further improve the pelletizing efficiency.

[0016] As a further improvement, the bottom of the sawdust powder bin and the third screw conveyor are both inclined to the horizontal plane, and the inclination angle of the bottom of the sawdust powder bin is the same as the inclination angle of the third screw conveyor, so as to facilitate the feeding of the third screw conveyor.

[0017] Preferably, the stirring tool comprises a stirring shaft driven by a motor, and a plurality of stirring blades extending in the radial direction are arranged on the stirring shaft.

[0018] Preferably, the first dust collector and the second dust collector are bag dust collectors.

[0019] Further improvement, a first screen is provided below the crushing chamber of the hammer mill, and the mesh number of the first screen is 3-4 mesh; a second screen is provided below the crushing chamber of the blade mill, and the mesh number of the second screen is 12-14 mesh. In this way, by reasonably setting the mesh size of the first screen, the particle size of most small wood blocks after hammer crushing can be controlled to about 50mm, firstly, the size of small wood blocks can be better automatically conveyed by the discharging conveyor, secondly, larger pieces of metal can fall off as much as possible and be adsorbed by the iron removal device, and thirdly, the loss of subsequent blade mill cutters can be reduced. By reasonably setting the mesh size of the second screen, the particle size of most wood chip powder can be controlled to about 1.2mm, which is convenient for further removal of mixed metal, conducive to extrusion granulation of the granulator, and can also reduce the wear of the blade of the blade mill, protect the extrusion die of the granulator, and further increase the output.

[0020] The blade crusher is preferably arranged under the ground to facilitate equipment layout and reduce dust spillage. The diameter of the negative pressure conveying pipe is preferably 250 mm to 300 mm to ensure that 3 to 4 tons of sawdust powder can be conveyed per hour.

[0021] As a further improvement, the negative pressure feeding pipe includes a horizontal section connected to the discharge port of the blade crusher and a vertical section whose lower end is connected to the horizontal section. The vertical section extends downward to a material settling section at the connection with the horizontal section, and a material clearing gate is provided on the material settling section. In this way, when the sawdust powder moves upward in the vertical section, some heavier metals or other materials mixed in the sawdust powder will settle into the material settling section, and then be cleared by opening the material clearing gate; the metal that cannot be removed by magnetic attraction can also be removed by the settling method, and the metal and other impurities in the sawdust powder can be better removed, so as to further improve the quality of the sawdust powder and protect the extrusion die of the pelletizer.

[0022] Furthermore, the horizontal section is provided with an air inlet on one side away from the vertical section, and the air inlet is connected to the air outlet of the fourth fan, and the wind pressure generated by the fourth fan assists in pushing the sawdust powder at the outlet of the blade crusher to move. When the sawdust powder is accumulated more or absorbs more moisture, the auxiliary conveying of the fourth fan ensures that the sawdust powder can be reliably conveyed through the negative pressure conveying pipe.

[0023] The beneficial effects of the present invention are as follows:

[0024] 1. Through the combined crushing of hammer mill and blade mill, the waste wood is first crushed into small wood pieces by hammer crushing, and then the small wood pieces are crushed into the required wood chip powder by blade mill. The wood chip powder formed in this way can meet the pelletizing needs of the pelletizer. At the same time, since the discharge conveyor is provided with an iron removal device, most of the metal in the small wood pieces will be sucked away and removed by the iron removal device during the movement of the discharge conveyor, which can better protect the service life of the blade of the blade mill and reduce the risk of production line shutdown.

[0025] 2. By setting up a wood block bin between the hammer mill and the blade mill, the discharging conveyor first conveys the small wood blocks formed by the hammer mill to the wood block bin for temporary storage, and then conveys the small wood blocks to the blade mill for crushing through the screw conveyor installed at the bottom of the wood block bin, which can better coordinate the crushing rhythm of the hammer mill and the blade mill, greatly improving the level of automation. Furthermore, by setting up multiple screw conveyors under the wood block bin to start conveying in turn, materials of different batches, different moisture contents, different fiber lengths, and different purities can be mixed and crushed into the blade mill, thereby improving the stability of the quality of the wood chip powder after crushing. This ensures the stability of the quality of the biomass fuel.

[0026] 3. An isolation room is set outside the hammer mill, which covers part of the feed conveyor and the discharge conveyor. The upper part of the isolation room is connected to the first dust collector through a negative pressure duct. On the one hand, the isolation room can better isolate the noise generated by hammer crushing. At the same time, the isolation room is in a negative pressure state through the first fan and the negative pressure duct, which reduces the dust from drifting outward during hammer crushing, greatly reduces noise and dust pollution in the workplace, and protects the health of operators. On the other hand, the sawdust powder is sucked away through the negative pressure feed pipe after being output from the blade crusher, and then separated by the cyclone separator. The entire conveying process is basically carried out in a closed space, which can make the blade crusher in a negative pressure state when crushing wood blocks, which can better reduce the outward drift of sawdust powder, increase the collection of sawdust powder, and greatly reduce dust pollution in the workplace. Ensure that the workplace meets the requirements of environmental protection, health, safety and explosion-proof.

[0027] 4. The transportation of sawdust powder is carried out in a relatively closed space, without the need for human intervention. The transportation is highly automated and efficient.

[0028] The above beneficial effects indicate that the present invention has a high degree of automation and reliability, can ensure the stable quality of the prepared biomass fuel, and make the workplace meet the requirements of environmental protection, health, safety and explosion-proof, and is currently a relatively effective and environmentally friendly production equipment for processing recycled waste wood materials.

[0029] The present invention also provides a process for preparing biomass fuel using the above production line, comprising the following steps:

[0030] Step 1: sort the recycled waste wood and send it to the feed conveyor;

[0031] Step 2: The feed conveyor feeds the waste wood into the hammer mill for hammering and crushing into wood blocks. The length of the wood blocks formed by hammering and crushing is ≤55mm.

[0032] Step 3: The wood blocks formed by hammering and crushing are sent to the wood block bin for mixing and temporary storage through the discharge conveyor. The wood blocks are magnetically attracted to remove iron while moving on the discharge conveyor.

[0033] Step 4: Use multiple screw conveyors to transport the wood blocks in different positions of the wood block bin to the blade crusher to crush them into sawdust powder. The particle size of the sawdust powder is ≦1.25mm;

[0034] Step 5: The conveying system conveys the sawdust powder to the pelletizer for extrusion and pelletization to form biomass fuel.

[0035] As a further improvement, the conveying system uses sedimentation to remove metal and impurities in the sawdust powder during the conveying process, so as to further remove metal and other impurities in the sawdust powder, protect the extrusion die of the pelletizer, and further improve the quality of biomass fuel.

[0036] This preparation process greatly improves the preparation efficiency of biomass fuel and ensures the stability of biomass fuel quality through the steps of picking and loading, hammer crushing, conveying and iron removal, temporary storage of wood blocks, rotating conveying, blade crushing and conveying and pelletizing of wood chip powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a stereogram of the present invention;

[0038] Figure 2 yes Figure 1 A magnified image of point A;

[0039] Figure 3 yes Figure 1 Enlarged view of point B. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0041] Figures 1 to 3 As shown, an automated production line for preparing biomass fuel using waste wood includes a crushing system 100 , a conveying system 200 and a pelletizer 300 .

[0042] The crushing system 100 includes a hammer mill 1 and a blade mill 2. The feed port of the hammer mill 1 is connected to the feed conveyor 3, and the discharge port of the hammer mill 1 is connected to the discharge conveyor 4. The output end of the discharge conveyor 4 is connected to the upper part of a wood block bin 5. The discharge conveyor 4 is provided with an iron removal device 41; the iron removal device 41 can be a permanent magnetic self-unloading iron remover or a magnetoelectric self-unloading iron remover, which is a device available on the market. The iron removal device 41 sends the sucked metal out from the side of the discharge conveyor 4 through a conveyor belt.

[0043] Four first screw conveyors 6 are installed at the bottom of the wood block bin 5. The four first screw conveyors 6 are arranged in parallel. The feeding end of each first screw conveyor 6 is connected to the internal space of the wood block bin 5, and the discharging end of each first screw conveyor 6 is connected to the feeding port of the blade crusher 2. The four first screw conveyors 6 are operated in turn to convey materials.

[0044] An isolation room 7 is provided outside the hammer mill 1, and the isolation room 7 covers part of the feed conveyor 3 and the discharge conveyor 4. The upper part of the isolation room 7 is connected to the first dust collector 8 through a negative pressure air duct 81; a first fan 82 is installed in the middle of the negative pressure air duct 81, and the first fan 82 generates negative pressure in the isolation room 7.

[0045] The conveying system 200 includes a negative pressure conveying pipe 9, a closed sawdust powder bin 10, a cyclone separator 11 and a second dust collector 12, one end of the negative pressure conveying pipe 9 is connected to the discharge port of the blade crusher 2, the other end of the negative pressure conveying pipe 9 is connected to the side gas inlet of the cyclone separator 11, the upper gas outlet of the cyclone separator 11 is connected to the air suction port of the second fan 13, and the air outlet of the second fan 13 is connected to the second dust collector 12 through a pipeline; the lower discharge port of the cyclone separator 11 is connected to the feed end of the second screw conveyor 14 through the air lock 111, and the discharge end of the second screw conveyor 14 is connected to the upper part of the sawdust powder bin 10;

[0046] Two third screw conveyors 15 are installed at the lower part of the sawdust powder bin 10, and the feeding end of each third screw conveyor 15 is connected to the internal space of the sawdust powder bin 10, and the discharging end of each third screw conveyor 15 is connected to the feeding port of a pelletizer 300;

[0047] The dust removal port of the second dust collector 12 is connected to the air intake port of the third fan 121 through a pipeline, and the air outlet of the third fan 121 is connected to the upper part of the sawdust powder bin 10 through a pipeline; the sawdust powder bin 10 is equipped with a stirring tool 17 driven by a motor 16.

[0048] The bottom of the sawdust powder silo 10 and the third screw conveyor 15 are both inclined to the horizontal plane, and the inclination angle of the bottom of the sawdust powder silo 10 is the same as the inclination angle of the third screw conveyor 15 .

[0049] The stirring tool 17 includes a stirring shaft 171 driven by a motor 16 , and a plurality of stirring blades 172 extending in the radial direction are disposed on the stirring shaft 171 .

[0050] The first dust collector 8 and the second dust collector 12 are bag dust collectors.

[0051] A first screen 1a is provided below the crushing chamber of the hammer mill 1, and the mesh number of the first screen 1a is 3-4 meshes; a second screen 2a is provided below the crushing chamber of the blade mill 2, and the mesh number of the second screen 2a is 12-14 meshes.

[0052] The blade crusher 2 is arranged under the ground; the diameter of the negative pressure feeding pipe 9 is 250 mm to 300 mm.

[0053] The negative pressure feeding pipe 9 includes a horizontal section 91 connected to the discharge port of the blade crusher 2 and a vertical section 92 whose lower end is connected to the horizontal section 91. The vertical section 92 extends downwardly to a material settling section 93 at the connection with the horizontal section 91. A cleaning gate 94 is provided on the material settling section 93.

[0054] An air inlet is provided on one side of the horizontal section 91 away from the vertical section 92 , and the air inlet is connected to the air outlet of the fourth fan 18 . The wind pressure generated by the fourth fan 18 helps to push the sawdust powder at the outlet of the blade crusher 2 to move.

[0055] The working process of this embodiment is as follows:

[0056] The waste wood recycled from daily life is first sent to the input end of the feed conveyor 3 after manual selection and simple dust removal. The feed conveyor 3 sequentially sends the waste wood to the feed port of the hammer mill 1. The hammer mill 1 hammers the waste wood into small wood pieces, and then the small wood pieces fall into the discharge conveyor 4. During the conveying process of the discharge conveyor 4, the metal objects carried by these small wood pieces will be sucked away by the iron removal device 41, and then these small wood pieces are transported to the wood block bin 5 for temporary storage. Then the four first screw conveyors 6 are started in turn to transport the small wood pieces at different positions of the wood block bin 5 to the blade mill 2 for further crushing to form the required wood chip powder 400;

[0057] The second fan 13 rotates to provide negative pressure to the negative pressure feeding pipe 9, and the negative pressure feeding pipe 9 sucks the sawdust powder 400 output from the discharge port of the blade crusher 2 through its horizontal section 91. At the same time, the wind pressure generated by the fourth fan 18 helps to push the sawdust powder 400 at the discharge port of the blade crusher 2 to move. After the sawdust powder 400 passes through the horizontal section 91, it moves upward along the vertical section 92 of the negative pressure feeding pipe 9. During the upward movement of the sawdust powder 400 in the vertical section 92, some heavier metals or other materials mixed in the sawdust powder 400 will settle in the material settling section 13, and better metal and impurity removal will be carried out. Then the sawdust powder 400 enters the cyclone separator 11 for separation, and most of the coarser sawdust powder 400 will fall into the cyclone separator 11. The wood powder 400 is then further dropped into the feeding end of the second screw conveyor 14 through the air-blocking device 111, and the second screw conveyor 14 then delivers the wood powder 400 into the wood powder bin 10; at the same time, some fine wood powder 400 is captured by the second dust collector 12 through the pipeline through the gas outlet at the upper part of the cyclone separator 11, and after the second dust collector 12 is cleaned, the fine wood powder 400 is also delivered to the wood powder bin 10 through the third fan 121 and the pipeline, and the coarser wood powder 400 and the finer wood powder 400 in the wood powder bin 10 are mixed by the stirring tool 17 to form wood powder 400 with stable quality, and the wood powder 400 is then delivered to the pelletizer 300 through the third screw conveyor 15 for pelletizing to form biomass fuel. Then, the biomass fuel can be sent to the use site after cooling and packaging.

[0058] This embodiment also provides a process for preparing biomass fuel using the above production line, comprising the following steps:

[0059] Step 1, sorting the recycled waste wood and sending it to the feed conveyor 3;

[0060] Step 2: The feed conveyor 3 feeds the waste wood into the hammer mill 1 for hammering and crushing into wood blocks, and the length of the wood blocks formed by hammering and crushing is ≤55mm;

[0061] Step 3: The wood blocks formed by hammering and crushing are sent to the wood block bin 5 through the discharge conveyor 4 for mixing and temporary storage. The wood blocks are magnetically de-ironized by the de-iron removal device 41 during their movement on the discharge conveyor 4.

[0062] Step 4: The wood blocks in different positions of the wood block bin 5 are transported to the blade crusher 2 by multiple first screw conveyors 6 in turn to be crushed into wood chip powder 400, and the particle size of the wood chip powder 400 is ≦1.25mm;

[0063] Step 5: The conveying system 200 conveys the sawdust powder 400 to the pelletizer 300 for extrusion pelletization to form biomass fuel. During the conveying process of the sawdust powder 400, the conveying system 200 removes metal and impurities contained in the sawdust powder 400 by sedimentation through the vertical section 92 of the negative pressure conveying pipe 9.

[0064] The above is only a preferred embodiment of the present invention. Any equivalent changes made by those skilled in the art according to the claims shall fall within the protection scope of this case.

Claims

1. An automated production line for preparing biomass fuel using waste wood, including a crushing system, a conveying system and a pelletizer. Features: The crushing system includes a hammer mill and a blade mill, the feed port of the hammer mill is connected to the feed conveyor, the discharge port of the hammer mill is connected to the discharge conveyor, the output end of the discharge conveyor is connected to the upper part of a wood block bin, and the discharge conveyor is provided with an iron removal device; a plurality of first screw conveyors are installed at the lower part of the wood block bin, the feed end of each first screw conveyor is connected to the internal space of the wood block bin, and the discharge end of each first screw conveyor is connected to the feed port of the blade mill, and the plurality of first screw conveyors are operated in turn to transport materials; An isolation room is provided outside the hammer mill, and the isolation room covers part of the feed conveyor and the discharge conveyor. The upper part of the isolation room is connected to the first dust collector through a negative pressure air duct, and a first fan is installed in the middle of the negative pressure air duct, and the first fan generates negative pressure in the isolation room; The conveying system comprises a negative pressure conveying pipe, a cyclone separator and a second dust collector, one end of the negative pressure conveying pipe is connected to the discharge port of the blade crusher, the other end of the negative pressure conveying pipe is connected to the gas inlet on the side of the cyclone separator, the upper gas outlet of the cyclone separator is connected to the air suction port of the second fan, and the air outlet of the second fan is connected to the second dust collector through a pipeline; the lower discharge port of the cyclone separator is connected to the feed end of the second screw conveyor through an air lock, and the wood chip powder sent out from the discharge end of the second screw conveyor is extruded and granulated by a granulator; The negative pressure feeding pipe comprises a horizontal section connected to the discharge port of the blade crusher and a vertical section whose lower end is connected to the horizontal section. A material settling section is extended downward from the connection between the vertical section and the horizontal section. A clearing gate is provided on the material settling section.

2. The automated production line for preparing biomass fuel using waste wood according to claim 1, Features: The conveying system also includes a sawdust powder bin, and the discharge end of the second screw conveyor is connected to the upper part of the sawdust powder bin; the lower part of the sawdust powder bin is equipped with a third screw conveyor, the feed end of the third screw conveyor is connected to the internal space of the sawdust powder bin, and the discharge end of the third screw conveyor is connected to the feed port of the pelletizer; The dust removal port of the second dust collector is connected to the air suction port of the third fan through a pipeline, and the air outlet of the third fan is connected to the upper part of the sawdust powder bin through a pipeline; the sawdust powder bin is equipped with a stirring tool driven by a motor.

3. The automated production line for preparing biomass fuel using waste wood according to claim 2, Features: A plurality of third screw conveyors are arranged at the lower part of the sawdust powder bin, and the discharge end of each third screw conveyor is connected to the feed port of a pelletizer.

4. The automated production line for preparing biomass fuel using waste wood according to claim 2, Features: The bottom of the sawdust powder bin and the third screw conveyor are both inclined to the horizontal plane, and the inclination angle of the bottom of the sawdust powder bin is the same as the inclination angle of the third screw conveyor.

5. The automated production line for preparing biomass fuel using waste wood according to claim 2, Features: The stirring tool comprises a stirring shaft driven by a motor, and a plurality of stirring blades extending in radial direction are arranged on the stirring shaft.

6. The automated production line for preparing biomass fuel using waste wood according to claim 1, Features: The first dust collector and the second dust collector are bag dust collectors; a first screen is provided below the crushing chamber of the hammer mill, and the mesh number of the first screen is 3-4 meshes; a second screen is provided below the crushing chamber of the blade mill, and the mesh number of the second screen is 12-14 meshes.

7. The automated production line for preparing biomass fuel from waste wood according to claim 1, Features: An air inlet is arranged on one side of the horizontal section away from the vertical section, and the air inlet is connected to the air outlet of the fourth fan. The wind pressure generated by the fourth fan helps to push the sawdust powder at the discharge port of the blade crusher to move.

8. A process for preparing biomass fuel using the production line according to any one of claims 1 to 7, The following steps are involved: Step 1: sort the recycled waste wood and send it to the feed conveyor; Step 2: The feed conveyor feeds the waste wood into the hammer mill for hammering and crushing into wood blocks. The length of the wood blocks formed by hammering and crushing is ≤55mm. Step 3: The wood blocks formed by hammering and crushing are sent to the wood block bin for mixing and temporary storage through the discharge conveyor. The wood blocks are magnetically attracted to remove iron while moving on the discharge conveyor. Step 4: Use multiple screw conveyors to transport the wood blocks in different positions of the wood block bin to the blade crusher to crush them into sawdust powder. The particle size of the sawdust powder is ≦1.25mm; Step 5: The conveying system conveys the sawdust powder to the pelletizer for extrusion and pelletization to form biomass fuel; The conveying system uses sedimentation to remove metal and impurities contained in the sawdust powder during the conveying process.

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