FI129482B - Method and apparatus for enriching pieces of woodchips containing extractive agents from woodchips provided with an even distribution of chip size and/or thickness - Google Patents

Abstract

The invention relates to an apparatus and a method for enriching chip pieces which contain extractives in a pile of chip pieces from wood chips (10; 10a) which have an even bit size distribution and / or even thickness distribution. The method comprises the following steps: - forming a homogeneous wood chip stream (1) of wood chips (10; 10a), comprising chip pieces having an even bit size distribution and / or even thickness distribution, - producing a homogeneous wood chip stream (11) which is accelerated to substantially the same speed by means of an accelerating device (20) and / or the medium of the accelerating device (20) from the homogeneous wood chip stream (1) - providing an inlet stream (12) of wood chips by directing the wood chip stream (11) accelerated to the same speed to a separating means ( Separating the chip pieces included in the wood chip inlet stream (12) with the separating means (30) into a group of different outlet streams (14) of wood chips, which outlet currents are based on density differences of the chip pieces or shape differences of the chip pieces included in said wood chips ( , that chips in the inlet stream (12) with a heavier density containing 0.5–10 v-% extractants substantially transmitted to at least a first outlet stream (14; 14c), which runs to at least a first chip pile (40; 402) along at least a first route (K4) and chips of a lighter density containing less than 0.5% by weight of extractives are mainly transferred to at least a second outlet stream (14a, 14b). ), which runs to at least a second chip pile (40) along at least a second route (K4), the second chip piles (40) lying along the average route (K4) of the outlet streams (14) before the first chip piles (40).

Description

The invention relates to a method as defined in claim 1 for enriching chips containing extracts from a wood pile having a uniform particle size distribution and / or a uniform thickness distribution. The invention also relates to an apparatus as defined in claim 12. More than 90% of the extract material in wood chips from the sawmill industry, in particular polyphenols, is generally derived from twigs. Branch material - on the other hand, is transported in the chips to a chip fraction containing mainly oversized or over-thick chips. The amount of over-thick and over-chipped fraction (hereafter: chip fraction) depends on the wood quality, chip type, wood hardness, chipping method, etc. The high density of branches, high extract content and low moisture in wood chips going to manufacture. Thus, oversized or over-thick chips are generally separated from the wood chips by mechanical screening. Mechanical screening (eg vibrating screen, drum and disc screens) or air screening are currently used to separate oversized and oversized chips. Counterflow screening can be used because the branched chips have a high specific gravity. In air flow screening, compressed air is supplied to the wood chips, at an angle to the direction of travel of the wood chips, also e.g. cyclones can be used. N The separated wood chip fraction with oversized or over-thick chips is re-chipped V 25 - nowadays, in order to obtain a homogeneous wood chip for the production of pulp. In this case, the wood chips obtained from conifers used for the production of the pulp generally comprise 5-10% of the branch material. In the production of chemical pulp, the aim is now to use homogeneous wood chips (softwood chips) with a length of 25 + -3 mm and a thickness of about 4 mm. In the manufacture of mechanical pulp 2 30 - homogeneous wood chips (softwood chips) with a length of 2 20 + -3 mm and a thickness of about 3 mm are used.

N Re-chipping over-thick and oversized chips reduces some of the problems in pulp production, but the quality of the pulp may remain poor. The resin and lignan contents of the thick branches of the branches are high. These extracts remain uncooked in the production of chemical pulp, increasing the amount of reject and reducing the yield. The extractants also increase the consumption of chemicals in the cooking process and the need for energy in mechanical pulping. The extractants in the branches also make bleaching more difficult and increase the consumption of chemicals.

By extractants in this application are meant water-soluble non-structural compounds soluble in wood and soluble in non-polar solutions, which are abundant in, inter alia, tree branches and heartwood. These include terpenoids, fats, polyphenols, carbohydrates and various inorganic salts.

- Extractives of particular interest are polyphenols, which mean lignans, flavonoids, stilones and tannins. These are particularly abundant in tree branches, bark, heartwood. Polyphenols, especially lignans and stilbenes, have been found to have several beneficial antioxidant, medicinal effects and, in addition, can be used in cosmetics.

- Several methods are known in the art for the separation of extractants, in particular polyphenols, from chips containing oversized and oversized chips. These known methods, without exception, are based on the separation of lignans and, more generally, extractants from oversized and oversized chips separated from the main chip fraction.

—According to the recovery of lignans, the separation methods used e.g. in patent publications FI 20031150 and FI 112041B. A method is known from the previous publication in which an oversized wood chip fraction or wood chips further sorted in its air stream (upstream) are further comminuted and sorted. Hydroxymatairesinol is recovered, for example, by extracting or separating the chips containing lignan O 25 - on the basis of its higher specific gravity by air separation (countercurrent method) N or water separation. A method is known from the latter patent publication, in which chips with a high specific gravity and which remain at the bottom of the water basin when the dried = chips are immersed in water are recovered from the dried oversized and / or over-thick chip fraction. 5 30 The problem in distinguishing between over-thick and over-sized chips is often poor yield, as oversized and over-thick wood chips have to be recovered by relatively coarse screening methods that separate only chips with a thickness of 8-40 m and a length of more than 500 mm. In addition, the further separation of chips containing extractives from the chip fraction comprising over-thick and oversized chips may cause problems and slow down the further process.

Finnish application publication FI-20050268, on the other hand, discloses a method in which lignans are recovered directly from a chopped and re-chipped homogeneous chip fraction. However, the recovery of the extractants is based on their direct extraction, which is a relatively slow and often expensive separation method and may slow down the overall process.

As a starting point for the above prior art, the object of the invention was to eliminate or at least alleviate the problems encountered in the above prior art.

Thus, the object of the invention was to provide a method and an apparatus used in it, which would enable the efficient recovery of extractants, in particular lignans, directly from homogeneous wood chips suitable for the production of pulp. Homogeneous wood chips suitable for the production of pulp comprise, firstly, wood chips from wood chips but also wood chips from the re-chipping of oversized and over-thick wood chips.

The method according to the invention and the equipment used therein achieve the above objectives.

Accordingly, the invention relates to a method as defined in claim 1 for enriching chips containing extracts from a wood chip having a uniform particle size distribution and / or a uniform thickness distribution. and the method comprises the steps of:

S K 25 - formation of a homogeneous wood chip stream from wood chips having a uniform particle size distribution and / or a uniform thickness distribution, Ao N - obtaining a homogeneous wood chip stream accelerated to substantially the same speed by means of an accelerator and / or accelerator medium 2

N - providing a wood chip feed current by directing an accelerated wood chip stream to the separation means at the same speed,

- separating the chips contained in the wood chip feed stream by a separating means adapted to divide the feed stream into a plurality of different wood chip output streams, said output streams being based on differences in specific gravity of chips contained in said feed stream or shape differences the chunks move mainly to at least one first outlet stream passing through at least one first chip stack with at least one first feed path and a feed stream with a specific gravity of less than 0.5% by weight of extractors one second path, wherein the second chip piles are located on the average path of the output streams before the first chip piles. - The term wood chip flow accelerated to the same speed means a continuous wood chip flow, the chips contained in which are arranged at the same speed, regardless of the weight, shape, etc. of the wood chips. - The term homogeneous wood chip stream means a wood chip stream with a uniform particle size distribution and / or a uniform thickness distribution. In wood chips with a uniform particle size distribution and / or a uniform thickness distribution, the length of the chips is 25 + -3 mm and the thickness is about 4 mm when chemically produced. N list mass.

N S 25 In the production of mechanical pulp, a homogeneous wood chip stream means S wood chips (softwood chips) with a chip length of 20 + -3 mm and a thickness of about 3 mm. The invention also relates to an apparatus according to claim 12 for enriching chips containing extractants from a wood chip, D 30, the chips of which have a uniform piece size distribution and / or a uniform thickness.

N distribution.

More specifically, an apparatus according to the invention for enriching chips containing extractants from a wood chip stack of wood chips having a uniform piece size distribution and / or a uniform thickness distribution comprises a storage of wood chips having a uniform piece size distribution and a thickness distribution. In addition, the apparatus includes an accelerator for providing an accelerated and homogeneous wood chip flow, separation means adapted to separate the chips contained in the wood chip feed stream into a plurality of different wood chip output streams based on at least - for receiving the output stream (s) from the chips, at least one second stack of chips for receiving the output stream (s) from the heavier chips in the feed stream, The invention is based on the formation of a homogeneous wood chip stream which is suitable, for example, for the production of mechanical and chemical pulp. This wood chip stream is brought to the same speed by a conveyor or the like, and then a homogeneous wood chip stream of the same speed is separated by a suitable method, such as spring or piece shape method, where heavier chips receive more kinetic energy and end up in farther piles / bins. By the above method, the heavier chip fractions can be separated quickly and in very good yield from the chip intended for pulping. Since the separation into different chip chips can be made on wood chips which are suitable as such for the production of pulp, the separation does not interfere with the production of the pulp. The closest prior art to the invention as defined in the claims is disclosed in D patent documents D1: GB 1177136 and D2 WO 0226404. Neither of these D 30 patent documents teaches or suggests the enrichment of extractable chips.

N launched.

The separation means according to a preferred embodiment of the invention comprises a collision plane mounted at an angle transverse to the flow direction of the wood chip feed flow, to provide different resilient wood chip outlet flows and further different wood chip outlet flows from the wood chip feed flow. The speed and direction of the bounced output streams are based on the specific gravity of the chips contained in the wood chip feed stream.

With such a separating means, a significant advantage is achieved that chips with a heavier specific gravity receive a higher output speed than chips with a lighter specific gravity. This difference in specific gravity in the starting speeds of the chips from the plane of impact and in the flight paths can be exploited when separating the chips into different chips.

In another preferred embodiment of the invention, the separating means comprises an impact plane mounted at an angle transverse to the flow direction of the above-mentioned wood chip supply flow, and further the apparatus comprises at least one first compartment and at least one second compartment positioned relative to the separating means. the lighter chips of the output stream are directed to different bins on the basis of their different kinetic energy: one of the first routes N and

Based on their lower kinetic energy, the chips containing less than 0.5% by weight of OV 25 extractors move mainly to at least one second outlet stream passing through at least one other passage of the chips pile of at least one second compartment, where = - the second chip boxes are located in the direction of output flow before the first chip piles.

O N In another preferred method, the operation of the separating means is based on the differences in the specific gravity of the chips in the feed flow as well as on the different average flatness, so that

that round and heavier chips containing 0.5% to 10% by weight of extractors pass through at least one first stack of chips and lighter and flatter chips with a specific gravity of less than 0.5% by weight mainly end up in at least one second stack of chips, the second chips being located in the direction of travel (K) of the chips before the first chips. In a preferred homogeneous wood chip suitable for the production of chemical pulp, the chips have a length of 25 + -3 mm and a thickness of about 4 mm. - In another wood chip homogeneous suitable for the production of mechanical pulp, the chips are 20 + -3 mm long and about 3 mm thick. In a further preferred embodiment of the invention, the method further comprises forming chipped wood chips by sawing wood discs from the tree trunk at the branch and chopping the discs and / or milling the wood discs from the tree trunk at the branch. Preferably, the sawn and / or milled wooden disc has a diameter of 1-4 cm, in which case it is sawn from the top side of the wooden frame, where the diameter of the wooden frame is less than 7 cm. Such wood chips contain more lignan than usual. The above-mentioned method preferably uses equipment comprising - sawing means and chopping means and / or milling means adapted to form a chipped wood chip by first sawing wood discs at the tree trunk N and then chopping these wood discs and / or milling the wood chips. . . S gosta, at the branch, wooden discs.

In the following, the invention and the advantages obtained by it will be described in more detail with reference to the accompanying figures.

Ia = Fig. 1A is a schematic side view of the apparatus according to the invention and the flow of chips in the apparatus.

LO o D Figure 1B schematically shows the method steps for processing wood chips

N before it enters the apparatus shown in Figure 1A. Figure 2 shows a flow chart of the method according to the invention.

Figures 3A and 3B illustrate flow charts of two main separation methods for a homogeneous chip stream. Figure 4 shows various alternative embodiments for the recovery of extractants from oversized and over-thick chips. Figures 1 illustrate a method and apparatus for enriching chips containing extractants into a chip stack using wood chips 10 having a uniform piece size distribution and / or a uniform thickness distribution of the starting material; 10a. The starting material here is a homogeneous wood chip 10; 10a, which has been brought into storage - from where it is taken for further processing. Stored wood chips 10; 10a is preferably a homogeneous wood chip with chips having a uniform piece size distribution and / or a uniform thickness distribution. The wood chips 10a can be adapted for the production of chemical pulp, whereby the length of the chips in stock is 25 + -3 mm and the thickness is about 4 mm. Wood chips 10a - can also be adapted for the production of mechanical pulp, in which case it is a homogeneous wood chips (softwood chips) 10; 10a having a chip length of 20 + -3 mm and a thickness of about 3 mm. Warehouse here means either a physical warehouse or simply a pile of wood chips. The stored homogeneous wood chips 10a are formed into a homogeneous wood chips stream 1. This wood chips stream 1 is supplied to an accelerator means 20, such as a conveyor N or the like. In Fig. 1, a continuous wood chip stream 1 is introduced to the conveyor along the path O K by gravity.

N <Q This accelerating means 20 provides a homogeneous wood chip stream 11 accelerated to substantially the same speed from the incoming homogeneous wood chip stream 1. To the formed accelerated homogeneous wood chip stream 11, a medium such as compressed air is accelerated. . o S The wood chip feed stream 12 is formed from the wood chip stream 11 by directing the accelerated wood chip stream 11 to the separation means 30 from the acceleration means at the same speed.

20. In Fig. 1, the feed streams 12 are directed along the flight path K2 to the separation means 30 from the conveyor 20. The chips contained in the wood chip feed stream 12 are separated by the separation means

30. The separating means 30 is adapted to divide the feed stream 12 into a number of different wood chip output streams 14. These output streams 14 are based on differences in the specific gravity of the chips contained in the feed stream 12 or on the shape differences of the chips. Fig. 3A shows the separation process with the separation means 30 at the principle level, and Fig. 1A shows in more detail the separation of the chips of the feed stream using the apparatus and method based on the specific gravity differences of the chips. The separation apparatus 30 comprises a collision plane 30a mounted at an angle transverse to the flow direction K2 of the wood chip supply current 12. The impact plane 30a bounces the chips of the feed stream 12 from the surface of the impact plane 30a in the direction K3. The direction K3 depends on the specific gravity of the chips contained in said wood chip feed stream 12 and the kinetic energy they retain in the elastic bounce from the surface of the impact plane 30a. In the apparatus shown in the figure, the chips of the feed stream 12 with a specific gravity of 0.5 to 10% by weight of extractants generally bounce to a higher trajectory K3 and move to the first output stream 14; 14c passing into the chip tray 40 of the first tray; 402 routes K4; K4! along. Instead, the chips of the feed stream 12, which contain less than 0.5% by weight of extractants, are mainly transferred to the outlet streams 14; 14a and 14; 14b. The output currents are adapted to flow to the chip pieces N 40 of the respective second tray boxes; 401 routes Q: Q4? and along K, K43. The compartments may have various raised N 25 upward projections or the like to guide the flight paths 1 <Q of the chips.

S I Both other chips 40; 401, 401 are located in the average path K4 of the output streams 14 before the first chip assembly 40; 402.

O D It can therefore be said that the method D 30 utilizing the separation apparatus 30 described above comprises, as the most important step in Fig. 3A, a separation step 400; N 401, which is based on the different output speed of the chips of the feed stream 12 due to their specific gravity and kinetic energy as the chips bounce off the impact plane 30a.

Thereafter, the chips of the feed stream are bounced from the resilient and impact plane 30a in the separation apparatus 30. The impact plane 30 is mounted at an angle of arrival suitable for the separation means with respect to the direction K2 of the supply current 12, such as an angle of 30 to 150 degrees. The collision plane 30a of the separating means 30 can also be movable, in which case the separating device is a conveyor with a hard or resilient collision plane. The impact plane bounces the chips of the feed stream 12 from the surface of the impact plane 30a in the direction K3, which direction depends on the specific weight of the chips contained in the feed stream 2 of said wood chips and the kinetic energy they receive in elastic bounce.

- The chips of the feed stream 12 are placed on different trajectories depending on their specific gravity (output streams 14), so that they can be sorted into different trays (sorting, step 500; 510). Various disadvantages or protrusions that hit the flight path of the output currents and divert the output currents to the desired compartments can be used for sorting into the trays.

- in another embodiment of the separation device 30 of the invention, schematically illustrated in Fig. 3B, a step 400 of separating the chips of the feed stream performed by the separation means 30; 402 is based on the differences in the specific gravity of the chips in the feed stream 12 as well as on the different shape. This separation device illustrated in Figure 3B is based on the finding that chips with more lignans are on average rounder than chips with a lower lignan content.

In this case, the difference may be based on different rolling resistance of the chips. The feed streams 12 are then placed on a downwardly extending rolling base, whereby the rounder chips roll further. In particular, chips containing 0.5 to 10% by weight of extractants, round N 25 and heavier in specific gravity, pass through at least one first stack of chips. Chips with a specific gravity of less than 0.5% by weight, which are lighter and flatter in their specific gravity, mainly end up in at least a second stack of chips, the second chips being in the direction of rolling of the chips before the first chips (sorting into different chips). 500; 550).

O D Figure 1B illustrates the formation of a homogeneous wood chip stream 10a from chipped wood chips 10; 10c. In this case, the chipped wood material, e.g. from the sawmill industry processes, is conveyed to a separator 106 with a chipped chip fraction 10; 10c separating the chip fraction 10b containing oversized and / or over-thick chips; 10b.

If wood chips specially adapted to the present process, which already have a high lignan content, are used, it is advantageous for the wood chips to come from a wood disc formed by sawing the tree trunk, wood discs at the branch and then chipping the wood discs. Another option for chipping is to cut wood discs from the trunk of the tree at the branch. Preferably, the sawn and / or milled wooden disc has a diameter of 1-4 cm, in which case it is sawn from the top side of the wooden frame, where the diameter of the wooden frame is less than 7 cm. The separator can be, for example, a mechanical sieve, compressed air in which the separation takes place upstream of the direction of travel of the chips or a cyclone. These general methods of separating wood chips, as well as mechanical wood screening methods and screens used therein, are known per se and reference is made to the literature known in the art and to the practices well known to those skilled in the art. Figure 2 illustrates the method described above on an even more general method: In the first step 80, the wood is chipped. Preferably, the chipped wood is a wood disc formed by sawing wood discs from the tree trunk, at the branch and then chipping the discs. Another option for chipping is by milling wooden discs from the trunk of the tree at the branch. - Preferably, the diameter of the sawn and / or milled wooden disc is 1-4 cm, in which case it is sawn from the top side of the wooden frame, where the diameter of the wooden frame is less than 7 cm. Of the wood chips thus obtained 10; 10c separates a wood chip fraction 10 containing oversized and / or over-thick chips; 10b (see the description of Figure 1B above). Chip fraction 10 comprising oversized and / or N over-thick chips; 10b, the chips are re-chopped S 25 by chipping in step 80. Thus, wood chips 10 are obtained; 10a having - a uniform piece size distribution and / or a uniform thickness distribution.

I = The formation of a homogeneous wood chip stream 1 generally also comprises wood chips 10 having a uniform piece size distribution and / or a uniform thickness distribution; 10a- storage step 150.

O N 30 However, it is also possible to carry out a chip fraction 10 containing oversized and / or over-thick pieces of wood chips; 10b further fractionation to recover the extractants in step 90. This is illustrated in more detail in Figure 4.

10 of the stored homogeneous wood chips; 10a, a homogeneous wood chip stream 1 is formed, the chip pieces having a uniform piece size distribution and / or a uniform thickness distribution (step 200). This is followed by the formation of a homogeneous wood chip stream 11 accelerated to substantially the same rate via the accelerator 20 and / or the accelerator 20 and the medium (e.g., compressed air) from the homogeneous wood chip stream (step 300). The chips are then separated from the feed stream 12 by a separating means 30 adapted to divide the feed stream 12 into different wood chip output streams 14, said output streams 14 being based on differences in the specific weights or shape differences of the chips contained in said feed stream 2. As stated above, the invention can also be carried out with a chip fraction 10 containing oversized and / or over-thick wood chips; 10b further fractionation to recover the extractants in step 90. Oversized and over-thick chips can be further fractionated 901 by, for example, mechanical screening. The screen is, for example, a mechanical screen, such as a vibrating screen, a drum screen or a disc screen. The mechanical screening methods for chips and the screens used in them are known per se and are referred to in the literature known in the art and to the general knowledge of a person skilled in the art. The oversized and over-thick chips 10b can be further made into a further fraction 904, for example by screening the chips based on a different shape, if the wood chips 10b are relatively fresh. This can be done as previously described if the oversized or over-thick chip fraction 10b is otherwise relatively homogeneous and uniform in size.

N N Chips containing heavier specific gravity are more round chips than chips with a lower lignan content. In this case, further fractionation can also be based on different rolling resistance of the chips. The feed stream of the oversized and / or over-thick chips is then fed to a rolling roller, so that the rounder chips roll further and can be separated into their own piles / trays.

LO 2 30 - Oversized and over-thick chips can also be made into a further fraction 903, N based on the direct extraction of extractants, in a manner known per se.

In addition, oversized and over-thick chips can also be made into a fraction 902 based on differences in the specific gravity of the chips in the wood chips. In the first embodiment of the further fractionation 902, the further fractionation is performed with compressed air or a cyclone as a countercurrent separation. These general air separation methods and devices and cyclones for wood chips are known per se and their performance is referred to in the literature known to the art and to the skill of the person skilled in the art. In another embodiment of the further fractionation 902a, the fractionation is performed by water separation, in which the chips having a high specific gravity and remaining at the bottom of the water basin are recovered from the oversized and / or over-thick chip fraction. Only some embodiments of the invention have been described above, and it will be apparent to those skilled in the art that the invention may be practiced in many other ways within the scope of the inventive idea defined in the claims.

OF OF O OF

N <Q

NN O

I a a

O O

LO o

O OF

Claims (18)

Claims A method for enriching wood chips containing extractives from a wood chip (10; 10a) having a uniform piece size distribution and / or a uniform thickness distribution in a chip pile, comprising the steps of: - forming a homogeneous wood chip stream (1) from a wood chip (10; 10a) the chunks have a uniform piece size distribution and / or a uniform thickness distribution, and in which the chips have a length of chips of 25 + - 3 mm and a thickness of about 4 mm or 20 + -3 mm and a thickness of about 3 mm in a homogeneous wood chip, (11) obtaining, via a medium of the accelerator (20) and / or the accelerator (20), a homogeneous wood chip stream (1), wherein the wood chip stream accelerated to the same speed is a continuous wood chip stream containing chips at the same feed rate; ) by directing at the same speed - an accelerated chip flow (11) to the separation means (30), adapted to divide the feed stream (12) into a plurality of different wood chip output streams (14), - separating the chips contained in the wood chip feed stream (12) by a separating means (30) adapted to divide the feed stream (12) into a plurality of different wood chip output streams (14), - such that said output currents are based on differences in the specific gravity of the chips contained in said feed stream (12) or on differences in the shape of the chips, characterized in that N | - the chips of the feed stream (12) with a specific gravity of 0.5% to 10 wt. 402) along the at least one first passageway and containing less than 0.5% by weight of extractants, the lighter feedstocks of the feed stream 2 having a specific gravity are mainly transferred to at least one second output stream (14a, 14b)> passing through at least one second stack (40; 401) O N 30 - one second path, where the second chip piles (40) are located in the average path of the output streams (14) before the first chip piles (40). A method according to claim 1, characterized in that the separating means (30) comprises a collision plane (30a) mounted at an angle transverse to the flow direction (K2) of the wood chip supply flow (12) and adapted to provide different output currents (14) for the resilient wood chips; 14a, 14b, 14c) of the wood chips feed stream (12), so that the output streams (14; 14a, 14b, 14c) are based on the specific weight differences of the chips contained in said wood chips feed stream (12), the heavier chips of the resilient outlet stream (13) the lighter chips of the resilient output stream are directed to chips in different compartments based on their different kinetic energy so that the chips of the feed stream (12) with a specific gravity of 0.5 wt% containing extractants move mainly to at least one first output stream , which is applied to at least one first tray (40; 402) ha chips with a specific gravity of less than 0.5% by weight, which have a specific gravity of less than 0.5% by weight, pass along the pile of pellets, mainly due to their lower kinetic energy, to at least one second output stream (14; 14a, 14b) applied to the stack of chips of at least one second tray (40; 401) along at least one second passageway, the second trays (40; 401) being located in the average passage path (K4) of the output streams (14) before the first trays (40). 40; 402). N N 25 Method according to Claim 1, characterized in that the operation of the separating means S (30) is based on differences in the specific weights and shape differences of the chips in the feed stream (12) so that they contain 0.5 to 10% of extractants the heavier chips D pass through at least one first chip pile S 30 (40; 402) and the lighter and flatter chips with a specific gravity of less than 0.5% by weight end up mainly at least in the second chip pile (40; 401), wherein the second chips (40; 401) are located in the direction of travel (K) of the chips before the first chips (40; 402). A method according to any one of the preceding claims, characterized in that the method further comprises mixing a pressurized medium such as a compressed air flow (P) with a wood chip (10; 10a) to obtain a homogeneous pressurized wood chip stream . Method according to one of the preceding claims, characterized in that the formation of a homogeneous wood chip stream (1) from the chipped wood chips - (10; 10c) further comprises the separation and re-chipping of oversized and / or over-thick chips with a uniform chip size distribution and / or a uniform thickness distribution. (10a) to provide. The method according to claim 5, further comprising forming the chipped wood chips (10; 10c) by sawing wood discs from the tree trunk at the branch and chopping the discs and / or milling the wood discs from the tree trunk at the branch. Method according to Claim 6, characterized in that the diameter of the sawn and / or milled wooden disc is 1 to 4 cm. Method according to one of Claims 5 to 7, characterized in that the formation of the homogeneous wood chip stream (1) further comprises storing wood chips (10; 10a) with a uniform piece size distribution and / or a uniform thickness distribution. OF Method according to one of Claims 6 to 8, characterized in that the wood chips (10; 10b) handling the oversized and / or over-thick chips are separated from the N wood chips (10; 10c) by mechanical screening or by a method based on - different rolling resistance of the chips depending on their shape. E: Method according to one of Claims 5 to 9, characterized in that chips containing oversized and / or over-thick chips, in particular lignans, are recovered by a method based on the difference in the specific gravity of the chips, such as by blowing compressed gas into wood. N to the chips running - counterclockwise to the direction of travel of the wood chips or by immersing the dry chips in water and recovering the sedimented chips. Process according to one of Claims 5 to 10, characterized in that the lignan is recovered by extraction from oversized and / or over-thick chips. An apparatus for enriching chips containing extractants by a method according to claim 1 from a chip stack of wood chips (10; 10a), the chips having a uniform piece size distribution and / or a uniform thickness distribution, the apparatus comprising a stock having a uniform piece size distribution and a thickness distribution; 10a), characterized in that the apparatus further comprises an accelerator (20) for providing an accelerated and homogeneous wood chip stream (11), separation means (30) adapted to separate the chips contained in the wood chip feed stream (12) into a plurality of different wood chip output streams (14), which output streams are based on differences in the specific gravity of the chips contained in the feed stream (12) of said wood chips or on the shape differences of the chips contained in the feed stream (12) such that - 12) the chips are mainly transferred to at least one first output current (14; 14c) passing along at least one first stack of chips (40; 402) with at least one first feed path and less than 0.5 wt% of feedstock having a specific gravity pass substantially into at least one second outlet stream (14a, 14b) passing through at least one to the second stack of chips (40) along at least one W second travel path, wherein The second chip piles (40) N N are located in the average path S 25 of the output streams (14) before the first chip piles (40). S z n Apparatus according to claim 12, characterized in that the apparatus comprises a plurality of chips (40) for receiving the output streams (14) of the separating means (30), the chips (40) comprising at least one of the lightest of the first chips (40). to receive the output stream (s) from the chips of the feed stream (12), to receive the output stream / output streams from the heavier feeds of the at least one second stack of chips (40), all other chips piles (40) being located in the center of the output streams (14) before the first piles of chips (40). Apparatus according to claim 12 or 13, characterized in that the separating means (30) comprises a collision plane (30a) mounted at an angle transverse to the flow direction (K2) of the wood chip feed stream (12), the feed stream (12) for resilient chips 30a) in a direction (K3) which depends on the specific gravity of the chips contained in the feed stream (12) of said wood chips. Apparatus according to claim 14, characterized in that the apparatus - further comprises at least one first compartment (40; 402) and at least one second compartment (4: 401), which compartments (492, 401) are arranged relative to the separating means, that the chips of the feed stream (12) with a specific gravity of more than 0.5% by weight of extractants bounce off the surface of the impact plane and fly, due to their higher kinetic energy, mainly to at least one first outlet stream (14; 14c) passing through at least one first tray ( 40; 402) in the chip pile, along the corresponding first path and containing less than 0.5% by weight of N extractants, lighter chips with a specific gravity bounce off the surface of the impact plane (30a) and fly mainly to at least one second output stream based on their lower kinetic energy ( 14; 14a, S 14b) passing through the second passageway corresponding to the stack I of the at least one second tray (40; 401) along which all the second trays (40; 401) are located = in the average path of the output streams (14) before the first trays (40; O 2 402). Apparatus according to one of Claims 12 to 15, characterized in that the stack of chips is located in a compartment formed by a collecting base with associated upwardly extending edges. Apparatus according to claim 12, characterized in that the apparatus further comprises sawing means and chopping means and / or milling means adapted to form chipped wood chips (10; 10c) by first sawing wood discs from the tree trunk, at the branch and then chopping these. wooden discs and / or by milling wooden discs from the trunk of the tree. Apparatus according to Claim 17, characterized in that the diameter of the wooden disc sawn and / or milled by the sawing means and / or the milling means is 1 to 4 cm. OF OF O OF N <Q NN O I a a O O LO o O OF