KR20190128936A - Lignin and moisture removal device and removal method in wood flour for WPC - Google Patents

Abstract

The present invention relates to a method and device for removing water and lignin in wood flour for WPC. The device comprises: a transfer unit including a casing which extends in the longitudinal direction and has an input hopper at one end thereof, an outlet at an opposite side to the same, and an outlet hole, and a screw feeder which is installed to be axially rotatable inside the casing and transfers wood flour introduced through the input hopper toward the outlet; and a plurality of electromagnetic wave generators emitting electromagnetic waves to the wood flour inside the casing to extract lignin and water from the wood flour by the action of electromagnetic waves. The method and device for removing water and lignin in wood flour for WPC of the present invention are excellent in the extraction efficiency of lignin and use the electromagnetic waves such that the environmental load is very low compared to the case of using chemicals. Since extraction is carried out simultaneously with transfer and stirring by using a continuously operated screw conveyor, it is possible to work continuously so productivity is good.

Description

Lignin and moisture removal device and removal method in wood flour for WPC}

The present invention relates to a device and a method for removing lignin (Lignin) and water from the material used in the production of WPC, and more particularly, lignin and water in wood flour for WPC extracting and removing lignin and water using electromagnetic waves The present invention relates to a removal device and a removal method.

For example, wood-based boards have been widely used as flooring materials for apartments. In addition to improving interior aesthetics, such flooring plays an important role in blocking harmful substances or moisture coming from the concrete floor.

For example, the steel floor is made of high pressure laminate (HPL) on the plywood to give a feeling of close to the natural floor. However, the steel floor has a weak wear resistance because there is no separate coating layer for maintaining the wear resistance, and thus scratches or scratches easily occur on the surface over time.

Recently, WPC (Wood Plastic Composite), which is a kind of synthetic wood manufactured by mixing wood and plastic, has been used as a building material. WPC is a material that is polymerized after adding wood powder to resins such as PP, PE, PVC, ABS, PET, PA6, PA66, synthetic rubber, and elastomers. It has several advantages of high strength and low price. In addition, WPC is also used in automotive interior and exterior materials and home appliances.

By the way, in the production of the WPC, the obstacle is the moisture and lignin (Lignin) components contained in the wood powder. The lignin component is a polymer aromatic polymer contained in cellulose in wood, and mainly serves as an adhesive interposed between cells, and partly as a reinforcing agent present in the cell membrane. It interferes with the combination of wood flour and synthetic resin, and is not environmentally friendly.

The lignin separation methods known to date include methods for decomposing and removing other components in wood to leave lignin as an insoluble residue, soluble lignin to elute, or using toxic chemicals or steam. Is difficult to extract efficiently. As such, extracting lignin in an economical manner while maintaining the nature of the tree is a difficult technique in practice.

As a result, in conventional WPC production, there is no choice but to use wood flour in a state containing lignin, and the binding strength between wood flour and synthetic resin is weak, and thus the quality cannot be improved any more.

Korean Laid-Open Patent Publication No. 10-2017-0130818 (reinforced flooring using WPC) Domestic Patent Publication No. 10-0681333 (WPC Environmentally Friendly Polyolefin / Wood Powder Composite)

The present invention has been made to solve the above problems, it is excellent in the removal efficiency of lignin and water, without generating pollutants, continuous operation is possible to provide a high productivity lignin and water removal device for wood powder and removal method for WPC There is a purpose.

WPC lignin and water removal apparatus for wood powder of the present invention for achieving the above object, extending in the longitudinal direction, one end of the input hopper, a casing having an outlet on the opposite side and the outlet hole is provided, A transfer part installed to be rotatable inside, and including a screw feeder for transferring wood powder injected through the feed hopper to the discharge port; Irradiating electromagnetic waves to the wood powder inside the casing, a plurality of electromagnetic wave generation unit for extracting lignin and water from the wood powder by the action of the electromagnetic waves.

Moreover, the cooling part which cools the wood powder discharged | emitted from a casing is provided in the discharge port side of the said casing.

In addition, on the inner wall surface of the casing, a reflection layer for reflecting the electromagnetic waves irradiated from the electromagnetic wave generator and causing the electromagnetic waves to be repeatedly irradiated to the wood powder is laminated.

Further, in order to achieve the above object, the WPC ligrin and water removal device for wood powder of the present invention extends in the longitudinal direction, and has an inlet hopper at one end thereof, an outlet at the opposite side, and a plurality of outlet holes. An inner casing which transmits electromagnetic waves radiated from the outside and guides the inside of the inner casing; and a conveying unit including a screw feeder installed in the inner casing so as to be rotatable and transferring wood powder injected through the inlet hopper to the outlet; An outer casing surrounding the conveying part and accommodating therein; A plurality of electromagnetic wave generators for irradiating electromagnetic powder to the wood powder inside the inner casing to extract the lignin and water from the wood powder inside the inner casing; It includes a vacuum pump to provide a vacuum environment inside the outer casing.

In addition, the outlet of the inner casing is provided with a cooling unit for cooling the wood powder discharged through the outlet.

In addition, the method for removing lignin and water in the wood powder for WPC of the present invention for achieving the above object, by grinding the chaff or reed chips or bamboo or wood debris, the grinding step of obtaining a wood powder having a particle size of 5 mesh to 250 mesh and ; An input step of injecting wood powder obtained through the grinding step into a casing in which an electromagnetic wave generating unit is installed; An electromagnetic wave irradiation step of irradiating electromagnetic powder to wood powder introduced into the casing to extract lignin in the wooden powder by the action of electromagnetic waves; A discharge step of discharging the wood powder from which lignin is removed through the electromagnetic wave irradiation step to the outside of the casing; It comprises a cooling step of receiving the wood powder discharged from the casing to cool.

In addition, the electromagnetic wave irradiated to the wood powder has a frequency of 915MHz to 2450MHz.

In addition, the vacuum holding step of providing a vacuum environment inside the casing as a process performed at the same time as the electromagnetic wave irradiation step; A transfer step for transferring the wood powder is further included.

The lignin and water removal apparatus and removal method in the wood powder for WPC of the present invention made as described above is excellent in the efficiency of removing lignin and water, and because of the electromagnetic wave, the environmental load is very low compared to the use of chemicals, continuous operation Extraction work is carried out at the same time by stirring conveyance using screw conveyor, so it is possible to work continuously and productivity is good.

1 is a view showing the overall configuration of the lignin and water removal apparatus in the wood powder for WPC according to the first embodiment of the present invention.
Figure 2 is a cross-sectional view for explaining the principle of operation of the lignin removal device shown in FIG.
Figure 3 is a block diagram showing a lignin and water removal apparatus in the wood powder for WPC according to a second embodiment of the present invention.
4 is a cross-sectional view for explaining the operation of the lignin removing device shown in FIG.
5 is a view showing the lignin and water removal apparatus in the wood powder for WPC according to a third embodiment of the present invention.
6 is a view showing another example of the lignin and water removal apparatus in the wood powder for WPC according to a third embodiment of the present invention.
Figure 7 is a block diagram showing a method for removing lignin in wood flour for WPC according to the first, second, third embodiments of the present invention.

Hereinafter, one embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

Basically, the present invention, which will be described later, is based on the fact that lignin and water can be removed from wood flour when an electromagnetic wave having a predetermined frequency is applied to the wood flour. The lignin and water-removed wood powder form a strong bond with the synthetic resin powder during the production of the WPC, thereby obtaining a WPC having strong physical and chemical properties.

The wood powder is a material for producing a WPC. In the production of WPC, natural fiber (natural cellulose fiber), flax, hemp, jute, kneaf, cotton, bamboo, bamboo, and coffe , Bran (rice bran, wheat bran, soybean pod, corn cup, etc.) may also be used as a material. In the following description, for convenience of description, all of the above available materials (materials mixed in the synthetic resin) are collectively referred to as wood powder.

1 is a view showing the overall configuration of the lignin and water removal device in the wood powder for WPC according to the first embodiment of the present invention, Figure 2 is a cross-sectional view for explaining the principle of operation of the lignin removal device shown in FIG. .

Basically, the lignin and water removal device 10 in the wood flour for WPC according to the first embodiment extends in the longitudinal direction, and has a hopper at one end thereof and a discharge port at the opposite side thereof, and a plurality of outlet holes are formed. A casing, the conveying unit being rotatably installed in the casing and including a screw feeder for conveying wood powder introduced through the feeding hopper to the outlet; The electromagnetic powder is irradiated to the wood powder inside the casing, and a plurality of electromagnetic wave generators are provided to extract lignin and water from the wood powder by the action of electromagnetic waves.

First, the casing 21 of the transfer part 20 extends in the longitudinal direction and has an input hopper 23 at one end and has an outlet 21c at the opposite end. The wood powder introduced through the input hopper 23 passes through the transfer space 20a by the operation of the screw feeder 30 to the discharge port 21c and then exits to the outside.

A plurality of electromagnetic wave generation units 33 are installed on the casing 21. The electromagnetic wave generator 33 emits electromagnetic waves into the casing 21 at regular intervals along the longitudinal direction of the casing 21. For example, the electromagnetic wave generator 33 may generate specific wavelengths such as 915 MHz, 3450 MHz, and 433 MHz. .

The energy of the electromagnetic wave irradiated from the electromagnetic wave generation unit 33 is transmitted to the wood powder to evaporate the water contained in the wood powder, so that the lignin is eluted or extracted. Lignin extracted from wood flour may take the form of a viscous fluidized liquid phase or vaporize. Increasing the energy of electromagnetic waves, lignin vaporizes into a gaseous state. Lignin can be released in the liquid or gaseous state.

Each of the electromagnetic wave generators 33 is connected to the controller 34. The control unit 34 operates the respective electromagnetic wave generating units 33 to adjust the irradiation time, the irradiation interval, and the like, as well as the output energy of the electromagnetic waves.

In addition, a reflective layer 29 is coated on the inner wall surface of the casing 21. The reflective layer 29 reflects the electromagnetic waves emitted from the electromagnetic wave generator 33 so that the electromagnetic waves can be reflected several times in the transport space 20a. As shown in FIG. 2, the electromagnetic wave irradiated from the electromagnetic wave generator 33 repeatedly hits and reflects on the reflective layer 29 to fill the interior of the transport space 20a with an electromagnetic atmosphere. Of course, the wood powder passing through the transport space 20a repeatedly impinges on the electromagnetic waves.

The wood flour is heated by dielectric heating by electromagnetic waves. Through the electromagnetic waves, when the molecules forming the wood rub against each other, some heat of friction occurs. The stronger the friction, the more heat is generated. The heat is generated deep in the wood powder, it is possible to remove moisture and extract lignin through this dielectric heating.

A plurality of outflow holes 21b are formed in the bottom of the casing 21. The outlet hole 21b is arranged along the longitudinal direction of the casing 21 and is a passage for discharging lignin extracted from the wood powder to the outside of the casing 21. The position of the outlet hole 21b can be changed as much as possible. For example, when ligrin is vaporized, the outlet hole 21b will be located at the upper side of the casing 21.

In addition, as shown in FIG. 1, screen mounting grooves 21a are formed in each outlet hole 21b, and a blocking screen 22 is fitted into the screen mounting groove 21a. The blocking screen 22 serves to prevent the wood powder from falling out. Naturally, the blocking screen 22 is denser than the minimum particle size of the wood flour. In addition, the mesh of the blocking screen needs to be as tight as the electromagnetic wave is not emitted.

The blocking screen 22 is located very close to the transfer screw. In other words, the outer tip line of the transfer screw 32 is almost in contact with the reflective layer 29 and the blocking screen 22 when the transfer screw is manufactured so that the wood powder does not stay on the top of the barrier screen 22. .

The screw feeder 30 is connected to the motor 25, the shaft 31 extending longitudinally and axially rotated in the casing 21, and the spiral feed screw 32 fixed to the outer peripheral surface of the shaft 31 It consists of. The screw feeder 30 itself has a general structure.

On the other hand, the cooling unit 36 is installed below the discharge port (21c). The cooling part 36 takes in wood powder after the process of the high temperature discharged | emitted from the casing 21, cools it to some extent, and sends it to the exterior after cooling to some extent. The reason why the cooling unit 36 is applied is to prevent the occurrence of fire.

In fact, since the wood powder heated by the electromagnetic wave generator 33 has a very high temperature inside the casing 21, since it is more likely to be discharged through the outlet 21c and combust with the oxygen, the cooling part 36 ) Is applied. The cooling method of the cooling unit 36 may be variously applied, such as air cooling or water cooling.

Figure 3 is a block diagram showing a lignin and water removal device in the wood powder for WPC according to a second embodiment of the present invention, Figure 4 is a cross-sectional view for explaining the operation of the lignin removal device shown in FIG.

Hereinafter, the same reference numerals as the above reference numerals refer to the same members having the same function, and repeated description thereof will be omitted.

As shown, the lignin removal apparatus 10 according to the second embodiment extends in the longitudinal direction, and has an input hopper at one end thereof, a discharge port at the opposite side, and transmits electromagnetic waves radiated from the outside to the inside thereof. Inner casing to be guided to, the axial rotation is installed in the inner casing and the transfer unit including a screw feeder for transferring the wood powder introduced through the input hopper to the outlet side; An outer casing surrounding the conveying part and accommodating therein; A plurality of electromagnetic wave generators installed in the outer casing and irradiating electromagnetic powder to the wood powder inside the inner casing, the electromagnetic waves extracting lignin and water from the wood powder inside the inner casing; It is connected to the inner casing and includes a discharge means for discharging the lignin and water extracted from the wood powder to the outside of the inner casing.

The transfer unit 20 includes an inner casing 41 having physical properties that allow electromagnetic waves to pass, and a screw feeder 30 that is rotatably provided in the inner casing 41. The screw feeder 30 is axially rotated by the motor 25 to transfer the wood powder as in the first embodiment.

The inner casing 41 is a member made of a material that transmits electromagnetic waves, such as glass, ceramic, or electromagnetic wave-transmitting plastic, and has a plurality of outflow holes (41a in FIG. 4). Since the physical force applied to the inner casing 41 at the time of conveyance of the wood powder in the conveyance part 20 is not large, you may manufacture with the above-mentioned material. In some cases, a reinforcing bar (not shown) for reinforcing the inner casing 41 may be applied to the outside of the inner casing 41.

The wood powder introduced through the input hopper 23 passes through the transport space 20a, receives the electromagnetic waves radiated from the electromagnetic wave generator 33, is heated, and is discharged in a state in which lignin and moisture are discharged therein, and thus the cooling unit 36 Is transferred to).

The outer casing 51 is a cylindrical member that surrounds almost the transfer portion 20 and is accommodated therein, and has a plurality of electromagnetic wave generating portions 33. The electromagnetic wave generation unit 33 is spaced apart along the longitudinal direction of the inner casing 41 and, as shown in FIG. 4, is symmetrical about the inner casing 41.

Electromagnetic waves emitted from each electromagnetic wave generator 33 pass through the inner casing 41 and heat the wood powder inside the inner casing 41. In the case of the second embodiment, unlike the first embodiment, the reflective layer 29 does not need to be applied. The interval of the electromagnetic wave generation unit 33 with respect to the inner casing 41 can be changed as needed.

The discharge means is an outlet hole 41a for discharging lignin and water extracted from wood powder to the outside of the inner casing 41. The inner diameter or position of the outlet hole 41a may vary as necessary.

5 is a view showing the lignin and water removal apparatus 10 in the wood powder for WPC according to a third embodiment of the present invention.

As shown, the lignin and the water removing device 10 according to the third embodiment, the outer casing surrounding the conveying unit 20, the conveying unit 20 is provided with the input hopper 23 and the cooling unit 36 at both ends (51), a plurality of electromagnetic wave generators 33 arranged on the outer casing (51), a control unit 34 for controlling the electromagnetic wave generators 33, and a vacuum pump for maintaining a vacuum pressure inside the transport space (20a) 27).

The transfer unit 20 includes an inner casing 41, a screw feeder 30 installed in the inner casing 41 so as to be rotatable, and a motor 25 for rotating the screw feeder 30.

Further, the inner casing 41 is a casing 42 which is hermetically housed in the outer casing 51, and an extension casing 43 which is connected to both ends of the casing 42 and exposed to the outside of the outer casing 51. It is composed. The transmissive casing 42 is a casing made of a material that transmits electromagnetic waves, and plays the same role as the inner casing (41 in FIG. 3) described with reference to FIG. 3.

The extension casing 43 and the outer casing 51 may be made of stainless steel and are coupled to each other by welding or the like.

In addition, a plurality of outlet holes 41a are formed in the upper portion of the permeation casing 42. The outflow hole 41a is a through hole arranged in the upper portion of the permeation casing 42, and is a hole through which the vaporized ligrin component and moisture are released. As mentioned above, the output energy of the electromagnetic wave generator 33 can be adjusted upward to vaporize the liquid ligline, so that the outlet hole 41a is formed in the upper portion.

On the other hand, the inner space of the outer casing 51 is connected to the vacuum pump 27. The vacuum pump 27 reduces the pressure in the outer casing 51 and the transfer space 20a at once and provides a vacuum atmosphere. As such, since the inside of the transfer space 20a is maintained in a vacuum, combustion of wood powder in the transfer space 20a is prevented, and the extraction of water and lignin from the wood meal proceeds more effectively. For example, ligrin and water can be extracted at a temperature below the vaporization point of ligrin under atmospheric pressure.

Reference numeral 55 is an auxiliary tank. The auxiliary tank 55 is a chamber for collecting and temporarily storing the extracted ligrin and water therein. Moisture and ligrin collected in the auxiliary tank 55 are treated in an appropriate manner.

6 is a view showing another example of the lignin and water removal apparatus 10 in the wood flour for WPC according to a third embodiment of the present invention.

As shown in FIG. 6, the lignin and the water removing device 10 may be manufactured vertically. The lignin and water removal apparatus 10 shown in FIG. 6 includes a plurality of electromagnetic wave generators 33 disposed in the vertically conveying part 20, the outer casing 51 surrounding the conveying part 20, and the outer casing 51. ), A controller 34 for controlling the electromagnetic wave generator 34, a vacuum pump 27 for providing a vacuum pressure to the transport space (20a), and an auxiliary tank (55) for collecting ligrin and water. In addition, an input hopper 23 is disposed at the upper end of the inner casing 41, and a cooling unit 36 is disposed at the lower end.

In the lignin and water removal device 10 having the above-described configuration, the transfer unit 20 serves as agitation rather than a transfer role. That is, the wood powder introduced into the inner casing 41 is continuously stirred by the action of the transfer screw 32, and irradiated with electromagnetic waves during the stirring process.

Lignin and water in the gaseous state generated in the wood powder during the stirring are passed through a plurality of discharge pipes 57 disposed at the periphery of the permeation casing 42 and then discharged to the external auxiliary tank 55. The discharge pipe 57 is a hollow pipe-like member fitted to each outlet hole 41a, and is inclined upwardly to allow ligrin and water to pass therethrough.

Figure 7 is a block diagram showing a method for removing lignin in wood flour for WPC according to the first, second, third embodiments of the present invention. The removal method through the removal device of the first, second and third embodiments is substantially the same.

As shown, the lignin removal method according to the first and second embodiments, the grinding step 101, the input step 103, the electromagnetic irradiation step 105, the transfer step 107, the ligrin and water collection step ( 108), the vacuum holding step 109, the discharge step 111, the cooling step 113.

First, the grinding step 101 is a process of obtaining wood flour having a particle size of 5 mesh to 250 mesh by grinding chaff or reed chips or bamboo or wood debris. If the particle size of the wood powder is smaller than 5 mesh, the durability of the wood powder will be reduced because it is not properly combined with the synthetic resin. In addition, if it is larger than 250 mesh, the content of wood flour in the WPC increases more than necessary, and the physical property is degraded.

The input step 103 is a process for inputting the wood powder obtained through the grinding step 101 into the input hopper 23, so that the wood powder reaches the interior of the transfer space (20a). As long as the screw feeder 30 continues to operate, the feeding step 103 may also proceed continuously.

As the wood powder is introduced through the feeding step 103, the microwave irradiation step 105, the feeding step 107, and the vacuum holding step 109 are simultaneously performed.

The electromagnetic wave irradiation step 105 is a process of causing the electromagnetic wave generator 33 to irradiate electromagnetic waves to the wood powder through the control unit 34. The frequency of the electromagnetic wave irradiated to the wood powder may be included in the range of 915MHz to 2450MHz. However, the frequency of the electromagnetic wave may vary as necessary.

The transfer step 107 is a process of transferring the wood powder being heated to the outlet 21c by operating the screw feeder 30. The wood flour is continuously stirred by the transfer screw 32 during the transfer step 107, so that there is no variation in the exposure time of the wood flour to the electromagnetic waves.

In addition, the vacuum holding step 109 is a process of operating the vacuum pump 27 to maintain the interior of the transport space (20a) in a vacuum environment. By maintaining the transfer space 20a in a vacuum, the extraction efficiency of lignin increases, and there is no burning phenomenon of wood powder.

The ligrin and water collection step 108 is a process that proceeds automatically as the vacuum maintenance step 109 is performed. As mentioned above, when the electromagnetic wave generator 33 is operated while the inside of the transfer space 20a is maintained in a vacuum, moisture and ligrin are discharged and collected in the auxiliary tank 55. Green and water collection stage.

Subsequent discharge step 111 is a process of discharging the finished wood powder in the transport space (20a) to the outside of the casing, the cooling step 113 receives the wood powder discharged from the casing to the cooling unit 36 to cool the processing. It is a process. The wood powder cooled through the cooling unit 36 is taken out to make WPC with lignin removed.

As mentioned above, although this invention was demonstrated in detail through the specific Example, this invention is not limited to the said Example, A various deformation | transformation is possible for a person with ordinary knowledge within the scope of the technical idea of this invention.

10: lignin removal device 20: transfer unit 20a: transfer space
21 Casing 21a Screen mounting groove 21b Outflow hole
21c: outlet 22: shut-off screen 23: feed hopper
25: motor 27: vacuum pump 29: reflection layer
30: screw feeder 31: shaft 32: transfer screw
33: electromagnetic wave generation unit 34: control unit 36: cooling unit
41: inner casing 41a: outflow hole 42: through casing
43: extended casing 51: outer casing 55: auxiliary tank
57: discharge pipe

Claims (8)

It extends in the longitudinal direction, the input hopper at one end thereof, the casing having an outlet on the opposite side, the outlet hole is provided, the shaft is installed rotatably inside the casing, to transfer the wood powder introduced through the input hopper to the outlet side A transfer part including a screw feeder;
The lignin and water removal apparatus for wood powder for WPC comprising a plurality of electromagnetic wave generation unit for irradiating electromagnetic powder to the wood powder inside the casing to extract lignin and water from the wood powder by the action of electromagnetic waves. The method of claim 1,
On the outlet side of the casing, the lignin and water removal apparatus in wood flour for WPC is provided with a cooling unit for cooling the wood powder discharged from the casing. The method according to claim 1 or 2,
The lignin and water removal apparatus for wood powder for WPC having a reflective layer laminated on the inner wall surface of the casing by reflecting the electromagnetic waves irradiated from the electromagnetic wave generating unit and causing the electromagnetic waves to be irradiated repeatedly on the wooden powder. An inner casing extending in the longitudinal direction, having an inlet hopper at one end thereof, having an outlet on the opposite side, having a plurality of outlet holes, and transmitting electromagnetic waves radiated from the outside to the inside thereof; A transport unit installed to be rotatable and including a screw feeder configured to transfer the wood powder introduced through the feed hopper to the discharge port;
An outer casing surrounding the conveying part and accommodating therein;
A plurality of electromagnetic wave generators for irradiating electromagnetic powder to the wood powder inside the inner casing to extract the lignin and water from the wood powder inside the inner casing;
WPC lignin and water removal apparatus comprising a vacuum pump to provide a vacuum environment inside the inner casing. The method of claim 4, wherein
The inlet of the inner casing lignin and water removal device for wood powder for WPC is provided with a cooling unit for cooling the wood powder discharged through the outlet. Milling chaff or reed chips or bamboo or wood debris to obtain wood flour having a particle size of 5 mesh to 250 mesh;
An input step of injecting wood powder obtained through the grinding step into a casing in which an electromagnetic wave generating unit is installed;
An electromagnetic wave irradiation step of irradiating electromagnetic powder to wood powder introduced into the casing to extract lignin in the wooden powder by the action of electromagnetic waves;
A discharge step of discharging the wood powder from which lignin is removed through the electromagnetic wave irradiation step to the outside of the casing;
Lignin removal method in the wood powder for WPC comprising a cooling step of receiving the wood powder discharged from the casing. The method of claim 6,
Electromagnetic wave irradiated to the wood powder is a method for removing lignin in wood flour for WPC having a frequency of 915MHz to 2450MHz. The method of claim 6,
A vacuum holding step of providing a vacuum environment inside the casing as a process performed simultaneously with the electromagnetic wave irradiation step;
Method for removing lignin in wood flour for WPC further comprising a transfer step for transferring wood flour.

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