DE102013104632A1 - Pelleting press and process for the production of pellets - Google Patents

Abstract

A pelletizing press and a method for producing pellets from material to be compressed, preferably from biomass for use as fuel in fireplaces, such as cellulose and / or lignocellulose-containing fibers, chips, or chips, has a flat die and a plurality of rollers rolling on the flat die has in order to press the biomass into pellets through bores formed in the flat die. In the pelleting press, a metering device and a chute adjoining the metering device are provided for each of the rollers for metering and feeding biomass to an area of the flat die that is in front of the roller in question in the direction of movement of the flat die, and a distribution device is provided for distributing biomass supplied by the pelleting press and for supplying the biomass to the dosing devices.

Description

The invention relates to a pelleting press for the production of pellets according to the preamble of claim 1 and to a method for the production of pellets according to the preamble of patent claim 18.

The production of pellets, also known as pellets or granules, from fines or compacted and / or molten material is already known. The production of pellets, or wood pellets, from preferably comminuted biomass, such as sawdust, dust or the like, is also already well known and in the field of renewable energies as a forward-looking technology for climate protection, especially in Europe propagated. The raw material used is usually chipboard from the woodworking industry, but it is also possible to utilize freshly felled stocks or non-recoverable types of wood or waste in the woodworking industry. For the market for wood pellets for the supply of small combustion plants in single or multi-family houses preferably pollutant-free base material is to be used. However, block power plants or special high-temperature furnaces for heat generation and / or for the production of electrical energy (combined cycle power plants) can also cleanly burn small amounts of polluted material (pellets of particleboard or MDF boards with or without a coating or a coating).

The wood pellets are usually produced in so-called pelleting presses, in which the material to be pressed is pressed by moving and / or active rolling rolls, also called roll-up rolls, through bores of a die. Through the holes, the material (biomass) is formed and discharged as strands from the holes. Under holes are understood to mean all openings, which are preferably carried out substantially cylindrical, are arranged in a die for the passage and shaping of the material. The holes can also have larger inlet areas (reductions) to improve the pressing process and be hardened or have hardened sleeves in the holes. In the area of the matrices, a distinction is made between flat and ring matrices. On ring matrices run for pressing outside or inside rollers on flat matrices roll the roller rollers circular (mill construction) from.

The invention preferably deals with flat dies, but may also be used with ring dies. Also, the material to be compacted may be not only biomass for incineration in fireplaces, but any pelletable material such as feed or food, coal, plastic or the like. The possibilities of processing and spreading the biomass, or the post-processing (shredding of the strands, cooling, storage, transport) of the pellets need not be discussed further. Reference is made to the prior art.

The document US 5,277,572 describes a pelleting press with a round die within which run three Kollerwalzen to press material to be pressed through the holes of the round die. For the supply of material to be pressed, a feed cylinder is provided which is arranged coaxially with and above the ring die. Within the feed cylinder, a distributor cone is arranged to form a passage for material to be pressed. The distance between distribution cone and delivery cylinder can be varied to change the passage for material to be pressed, thus regulating the inflow of material to be pressed into the area within the circular die.

From the document EP 2 241 434 A2 a plant for the production of pellets from biomass is known, wherein the biomass is introduced before the pelleting press in a metering device, which consists of a scattering device and arranged underneath endlessly circulating forming belt. With the scattering device while the biomass is scattered as a mat on the forming belt, so that a mat is formed with uniform basis weight. The mat is then fed to a dissolving device, which again separates the biomass contained in the mat. The biomass thus dissolved is then fed to a pelleting press.

The document DE 10 2009 051 481 A1 describes a pelleting press for the production of pellets from biomass, with a flat die and a plurality of rolls, which are arranged above the flat die. It is further described that a scattering device can be provided in order to be able to supply biomass separately for each roller. How such a scattering device could be formed is not described in detail in the document.

Due to the worldwide acknowledged global warming, the industry is forced to accelerate and cheapen the large-scale industrial production of wood pellets. There is therefore a need for efficient pelleting presses, with which a high throughput of biomass can be achieved by the press and have a correspondingly high production capacity in the production of pellets. At the same time, the system costs and the operating costs should be as low as possible in order to be able to produce pellets at the lowest possible cost.

An essential element that determines the production performance of a pelleting press is the die. At the same time, the die, as a wearing part, is a major cause of planned and unplanned maintenance, with the pelleting press usually being shut down for longer periods of maintenance, which can result in significant production downtime.

Especially in pelleting presses, which are designed for the large-scale industrial production of pellets, high demands are placed on the die to achieve the highest possible throughput of biomass by the pelleting press and to achieve a correspondingly high production capacity of pellets. In this case, it should be particularly taken into account that irregularities can form in the biomass to be compacted, for instance because clumps or accumulations form in the residual layer of the biomass which remains on the matrix during operation of the pelleting press, in particular because of the presence in front of the rolls Do not compress or push biomass quickly and / or evenly enough. If a roller then passes over such an irregularity, then this can lead to a large part of the force with which the roller exerts a pressure perpendicular to the surface of the die concentrating on the small, restricted area of the irregularity, so that the die is locally closed a very high force is loaded, resulting in damage and increased wear of the die and can lead in extreme cases to breakage of the die. To reduce this risk, the die can be made more resistant by, for example, increasing the diameter of the die and / or increasing the thickness of the die, resulting in correspondingly increased plant costs for the pelleting press.

There is therefore a conflict of objectives between the requirements of low damage and failure frequency, high production capacity and low system costs.

It is therefore an object of the present invention to provide an improved pelleting press which allows an improved solution of the conflict of goals. In particular, it is an object of the present invention to provide a pelleting press which can achieve high production efficiency with reduced failure frequency. At the same time a method is to be created, with which it is possible to store the material to be pellet gently and evenly on the die.

These and other objects of the invention are achieved by a pelleting press as defined in claim 1. Further preferred embodiments are set forth in the dependent claims.

As a solution, a pelleting press is specified for the production of pellets of material to be pressed, preferably biomass for use as fuel in fireplaces, wherein the biomass of cellulosic and / or lignocellulosic fibers, chips, or chips, the pelletizing a Flachmatrize and a plurality of rolls rolling on the flat die, to compress the biomass through holes formed in the flat die to form pellets, wherein for each of the rolls a metering device and a downcomer adjoining the metering device are provided for metering and for supplying biomass to a region of the flat die which lies in the direction of movement of the flat die in front of the respective roll, and wherein a distributor device is provided, for distributing biomass, which is supplied to the pelleting press, and for feeding the biomass to the metering devices.

It is thus provided for each roller its own metering device, which ensures that a respective tuned, uniform amount of biomass can be applied to the flat die to be pressed by the respective roller. The chutes allow thereby that each metered amount of biomass can be performed as directly as possible in front of the roller. The metering devices are in turn fed by a distributor device which distributes a stream of biomass supplied to the pelleting press to the plurality of metering devices. In this way, the flat die before each roll is covered with a uniform amount and with a homogeneous distribution of biomass, which are then pressed by the respective rollers. As a result, therefore, each roller can work at a consistently optimal operating point and perform a consistently high compression work, so that the pelleting press can achieve a consistently high production output. At the same time it avoids that due to uneven feeding of the flat matrix with biomass to unwanted accumulation of biomass. The risk of local damage or even the occurrence of fractures of the flat die can therefore be reduced without the need for oversizing the flat die.

Preferably, the distributor device has a distributor cone and a distributor ring disposed below the distributor cone, wherein a plurality of apertures are formed in the distributor ring, each aperture being arranged and configured to allow particles of the biomass to pass through the apertures into one below the aperture to allow arranged metering device. In this way, a mechanically simple, low-maintenance and reliable Distributor device can be realized, which allows an efficient distribution of the biomass on the metering devices.

A scraper arrangement may be arranged between the distributor cone and the distributor ring, with at least one scraper extending in the radial direction over at least part of the distributor ring, wherein further drive means are provided for rotationally driving the scraper arrangement so that the at least one scraper passes over strips the distributor ring. The scraper or scrapers efficiently ensure that biomass accumulating on the distributor ring is conveyed into the ports and further into the dosing devices.

The openings are preferably designed to be closed. This may in particular allow to suspend individual rolls from production and to some extent "shut down", for example in times when only a lower production capacity is required.

Within the metering devices, in each case a roller arrangement with a plurality of rollers can be arranged for metering the biomass. The rollers may be further configured and configured to comminute and / or dissolve the biomass. In particular, the rollers may be formed as spoke rollers, as knife rollers or as rollers on whose peripheral surfaces in regular patterns projections and / or depressions, in particular in diamond shape. In this way, the metering devices can simultaneously serve to dissolve and loosen the biomass, and / or to break up the biomass, so that larger lumps, which may possibly be contained in the biomass supplied to the pelleting press, do not reach the flat die and eventually gain there Can cause problems.

A storage space is preferably formed above the roller arrangement in the metering device in order to receive and temporarily store biomass that has been passed through an opening associated with the metering device. In this way, the metering device can be decoupled from the distributor device and it can be ensured that the respective roller can be continuously supplied with a constant stream of biomass.

The chutes may each have an outlet opening bounded by a lower outlet edge. Preferably, the lower outlet edge is arranged at a height h above the flat die, wherein the height h is less than 2 times, preferably less than 1.5 times and more preferably less than 1.0 times the press gap height. The height h can also be zero. In this way, the lower outlet edge can simultaneously serve to level a remainder of biomass which, after being pressed by one of the rollers, remains on the rolling surface of the flat die, or to completely clear it off from zero in the case of a height h , and strip off excess biomass from the rolling surface. The stripped biomass is preferably conveyed back to the distribution device in order to be re-dosed and fed via a chute of a roller for re-pressing. The outlet edge preferably has an oblique structure counter to the direction of movement in order to improve the "clearing effect" of the flat die.

Preferably, the lower outlet edge is arranged to lie in a region between the press nip formed between the associated roll and the flat die and a perpendicular tangent to the associated roll. The vertical is preferably perpendicular to the rolling surface of the flat die. In this way, the biomass supplied through the outlet opening in the direction of the roll is fed almost directly into the press nip.

The chutes may each have a first chute section and a second chute section, wherein the second chute section is bounded on its side facing away from the associated roller by an arcuately curved wall, wherein the lower outlet edge is defined by a lower end of the second chute section. The curvature causes biomass particles to flow through the chute. Furthermore, the side of a chute facing the associated roller is preferably also delimited by an arcuately curved wall, so that a horizontal cross section of the lower chute section tapers in the falling direction of the particles of the biomass through the two curved walls. The biomass can be discharged in this way via an outlet opening which extends over the entire width of the rolling surface of the flat die, but has only a small extension in the direction of movement of the flat die. In other words, a long, narrow stream of biomass is applied to the flat die, which extends over the entire width of the flat die and is long in this sense, but in the direction of movement of the flat die has only a substantially smaller horizontal extent and is narrow in this sense , In this way, the biomass can be deposited approximately as a homogeneous, even mat on the rolling surface of the flat die.

More preferably, the arcuately curved wall in the region of the lower Auslasskante be curved so that a tangent to the facing away from the roller, curved wall in the region of the lower outlet edge an angle α with the rolling surface of the flat die assume, between 20 ° and 55 °, preferably between 25 ° and 45 °, particularly preferred between 30 ° and 40 °. The biomass particles that flow through the chute vertically, in this way a change in direction so that they do not impinge perpendicular to the rolling surface of the flat die, and it is avoided that the particles bounce due to their kinetic energy, for example, again from the flat die, or abut other biomass particles that have remained on the rolling surface of the flat die as remnants of a previous compression by another roller and set in motion. It can thus reduce the likelihood that due to the supply of biomass arise irregularities in the distribution of biomass on the rolling surface. It is particularly preferred that the fall shafts have a height and an angle α, which are dimensioned such that the particles emerging from the respective outlet opening of the biomass have a velocity component in the horizontal direction which on average assumes a value which is in one Range between 80 and 120%, preferably between 90% and 110%, in particular about 100% of the speed of the rolling surface is. Therefore, when exiting the outlet port, the biomass particles have substantially the same speed in the horizontal direction as the speed of the rolling surface at that point, which is the rate of rotation of the flat die multiplied by the radius multiplied by 2π. The biomass particles can therefore easily be deposited on the rolling surface, without resulting in shock-like kinetic energy transfer for acceleration and deceleration, which could lead to unwanted movement of the biomass particles and disruption in the formation of a uniform and homogeneous occupancy of the rolling surface.

Means may further be provided to vibrate the chutes and / or the distributor device, in particular the distributor cone and / or the distributor ring in vibration. In this way, it is possible to ensure improved transport of the biomass and / or reduce deposition of biomass particles.

The solution for the method for the production of pellets is that the biomass is distributed via a distributor to the number of rollers and each fed to a metering device, the metering the biomass dosed transferred into a chute and the biomass in the chute to a range of Flat die is supplied, which is in the direction of movement of the flat die in front of the respective roller.

It is particularly advantageous if the biomass is intermediately stored by the metering device in a gap and thus can be controlled and passed on evenly.

In particular, it would be advantageous if the biomass is transferred with a speed component in the horizontal direction from the chute of the flat die, which on average assumes a value in a range between 80% and 120%, preferably between 90% and 110%, in particular is about 100% of the speed of the rolling surface.

Further advantageous measures and embodiments of the subject matter of the invention will become apparent from the following description with the drawing.

Show it:

1 a plan view of a circular flat die and a plurality of rolling rolls of a pelleting press according to an embodiment thereof;

2 a side view in section after 1 ;

3 a side view of a pelleting press according to an embodiment;

4 a plan view of a pelleting press according to an embodiment; and

5 Details of the supply of biomass in the area of a roll of a pelleting press according to one embodiment.

The 1 and 2 show a section of a pelleting press 3 according to one embodiment, wherein the supply of the biomass 1 for the sake of clarity is not shown.

The 1 shows a plan view of a circular flat die 4 and several rolls rolling on it 5 in four pressing devices respectively press frames, 12 , This number is not limiting and may, depending in part on the inside or outside diameter of the flat die 4 , a variety of pressing devices 12 in the pelleting press 3 be arranged. The flat die 4 with the rolling surface 19 is movable in the pressing devices 12 by means of bearings 9 stored and is powered by at least one drive 27 for performing a circular movement about the axis of the flat die 4 driven. Optional drives of the rollers 5 in the pressing devices 12 are not shown. The rollers 5 are in the pressing devices 12 arranged substantially stationary, so that the rollers 5 with their surfaces on the rolling surface 19 the flat die 4 roll off or on the biomass 1 Unroll on the rolling surface 19 rests. This compression space 2 becomes sideways through the side walls 11 limited.

In 2 can be recognized in one cut 1 the pelleting press 3 on a foundation 14 , wherein in the schematic sectional view of a press frame 21 with a multi-part press frame, consisting of a lower crosshead 7 and two pull tabs 6 is arranged, wherein the axle mounted in the pull tabs 16 the roller 5 with the help of appropriate machine elements, respectively bearing, is kept movable. While rolling on the rolling surface 19 the flat die 4 becomes the biomass 1 through the holes 13 to pellets 10 pressed. The flat die driven in this example 4 is by means of bearings 9 on the lower crosshead 7 supported. It is understandable that in the drawing, the representation of the pressing device 12 or the press racks 21 Priority and has been omitted for reasons of clarity on the presentation of obvious and known mechanical equipment parts. To illustrate possible variants of a built press frame 21 has the pressing device 12 on the left side no own upper crosshead 8th on, as shown in the right-hand illustration. With the help of appropriate bearings, the axis 16 the roller 5 the function of the upper crosshead 8th take. In a preferred embodiment, multi-part press frame locks or bolts 15 on, with which these can be decomposed quickly. It is helpful if parts of the press frame 21 working surfaces 17 with which a lifting device, for example a crane hook (not shown) and / or at least one forklift fork, with a part of the press frame 21 is operatively connected and at least this part of the pelleting press 3 simply remove or can bring in.

With reference to the 3 to 5 will now be the supply of biomass 1 on the rolling surface 19 the flat die 4 described in detail.

The 3 represents a side view of a pelleting press 3 such as the fragmentary in the 1 and 2 illustrated pelleting press 3 , 4 shows a plan view of the distribution device for distributing the biomass 1 on the individual pressing devices 12 ,

Like in the 3 and 4 shown, becomes biomass 1 fed vertically from the top of the pelleting press to encounter a distributor device having a distributor cone 31 and one below the distribution cone 31 arranged distribution ring 34 having. The biomass 1 is doing from the distribution bonus 31 distributed substantially around the perimeter of the distribution cone 31 distributed on the distribution ring below 34 impinge. Between the distribution ring 34 and the distribution bonus 31 is a scraper arrangement 32 arranged with one or more scrapers 33 is provided, the or in the radial direction at least over a part of the distribution ring 34 extend. Drive means (not shown) are further provided for the scraper assembly 32 to turn, leaving the at least one scraper 33 over the distribution ring 34 roams.

With reference to the 4 , which is a top view of the pelleting press of the 3 represents are openings 35 shown in the distribution ring 34 are formed, so that biomass 1 through the openings 35 through in below arranged metering devices 36 can get. It can also be provided that the openings 35 are designed to be closed to the flow of biomass 1 in one under the closed opening 35 lying metering device 36 to interrupt, for example, when a pressing device 12 is out of order or not needed.

It is preferred that walls 48 are provided, which the surface of the distribution ring 34 in the radial direction outwardly and inwardly (not shown) limit, so that a kind of annular trough is formed, in which of the distributor cone 31 distributed particles of biomass 1 caught and in the area of the distribution ring 34 being held.

Referring again to the 3 It can be seen that in the area below the distributor device and above the flat die 4 a plurality of metering devices 36 and manholes 40 are arranged, each roller 5 respectively a pressing device 12 a metering device 36 and one under the metering device 36 arranged and connected to this chute 40 assigned. It can do so through a dosing device 36 continuously for a roller 5 amount of biomass for compression 1 be dosed and over the chute 40 this one roller 5 be supplied.

Within the metering devices 36 is in each case a roller assembly with a plurality of rollers 38 arranged to serve the biomass 1 to dose, and preferably also can serve, the biomass 1 to crush and / or dissolve. For this purpose, the rollers 38 For example, be designed as a spoke rollers or as a knife rollers. The rollers can also act as rollers 38 be formed on the peripheral surfaces in regular patterns projections and / or depressions, in particular in diamond and / or diamond shape, are formed.

In the dosing device 36 is a storage space above the roller assembly 37 educated. biomass 1 passing through an opening 35 from the distribution ring 34 falls, enters the storage space 37 and can accumulate there before the biomass 1 through the rollers 38 from the storage room 37 discharged, dosed and into the chute 40 is discharged. The storage space 37 serves as a buffer for biomass 1 . 50 that the metering device 36 from the supply of biomass 1 is decoupled by the distribution device and a steady, even stream of biomass 1 dosing and into the chute 40 can carry.

The storage space 37 and / or the area of the distributor device and / or in the chute 40 may be means of conditioning the biomass 1 be provided, such as humidification, evaporation, heating, inerting.

The manholes 40 are preferably with an upper chute section 41 and a lower chute section 42 educated.

At the lower end of the lower chute section 42 is one from a lower outlet edge 46 limited outlet opening 45 trained by the biomass 1 passing through the chute 40 flows, for storage on the rolling surface 19 is issued.

The area of storage of biomass 1 on the rolling surface 19 in the direction of movement 47 the flat die 4 in front of an associated roller 5 is in more detail in the 5 shown. Like in the 5 to recognize is the lower outlet edge 46 at a height h above the flat die 4 arranged. The lower outlet edge 46 can be used simultaneously for leveling biomass residues 1 serve, which is still on the rolling surface 19 are located. The height h can, for example, as a multiple of the press nip height between the roller 5 and the rolling surface 19 be designed such as less than 2.0 times, less than 1.5 times or less than 1.0 times the Pressspalthöhe. The height h can also be zero, leaving the bottom outlet edge 46 directly on or immediately above the rolling surface 19 strips and so remains of biomass 1 strips off on the rolling surface and removed. The stripped biomass 1 can be returned to the distribution device to re-dosed one of the rollers 5 to be fed. Preferably, the outlet unit 46 against the direction of movement 47 an oblique structure to the "clearing effect" of the flat die 4 to improve.

Like in the 5 further shown, the lower outlet edge 46 be arranged in the immediate vicinity of the press nip, for example, in which the outlet edge 46 in the area between the press nip and a vertical S, which is the associated roller 5 affected.

The second chute section 42 has, preferably two arcuately curved, walls 43 . 44 on which the second chute section 42 on the roller 5 facing side and on the roller 5 Limit facing away, so that a horizontal cross section of the lower chute section 42 in the direction of the particle of biomass 1 rejuvenated.

Preferably, the arcuately curved wall 43 at the lower outlet edge 46 curved so that a tangent T attached thereto makes an angle α with the rolling surface 19 the flat die 4 which is between 20 ° and 55 °, preferably between 30 ° and 45 °, more preferably between 32 ° and 40 °. In particular, the angle α, as well as the drop height of a respective chute 40 , so be measured that from the outlet opening 45 emerging particles of biomass 1 have a horizontal speed of between 80 and 120%, preferably between 90% and 110%, in particular about 100% of the speed of the rolling surface 19 , respectively the flat die 4 , that is below the outlet edge 46 moved over.

LIST OF REFERENCE NUMBERS

1

biomass

2

compression chamber

3

pelleting press

4

flat die

5

roller

6

pull tab

7

Crosshead below

8th

Cross head above

9

camp

10

pellets

11

Side wall

12

pressing device

13

drilling

14

foundation

15

bolt

16

axis

17

attack surface

19

rolling surface

21

press frame

27

drive

31

distribution cone

32

A scraper assembly

33

scraper

34

distribution ring

35

openings

36

metering

37

storage space

38

roll

40

chute

41

Chute section above

42

Down shaft section below

43

wall

44

wall

45

outlet

46

outlet edge

47

movement direction

48

wall

H

height

S

vertical

α

angle

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 5277572 [0005]
• EP 2241434 A2 [0006]
• DE 102009051481 A1 [0007]

Claims (20)

Pelleting press ( 3 ) for the production of pellets ( 10 ) from material to be pressed, preferably from biomass ( 1 ) for use as fuel in fireplaces, said biomass ( 1 ) consists of cellulose and / or lignocellulosic fibers, shavings or chips, the pelleting press ( 3 ) a flat die ( 4 ) and a plurality of on the flat die ( 4 ) rolling rolls ( 5 ) to the biomass ( 1 ) through in the flat die ( 4 ) drilled holes ( 13 ) to pellets ( 10 ), characterized in that for each of the rolls ( 5 ) each a metering device ( 36 ) and to the dosing device ( 36 ) subsequent chute ( 40 ), for the metering and supply of biomass ( 1 ) on an area of the flat die ( 4 ), in the direction of movement ( 47 ) of the flat die ( 4 ) in front of the relevant roller ( 5 ), and that a distribution device is provided for distributing biomass ( 1 ), the pelleting press ( 3 ), and for supplying the biomass ( 1 ) to the dosing devices ( 36 ). Pelleting press ( 3 ) according to claim 1, characterized in that the distributor device has a distribution cone ( 31 ) and one below the distribution cone ( 31 ) arranged distribution ring ( 34 ), wherein in the distribution ring ( 34 ) a plurality of openings ( 35 ) are formed, each opening ( 35 ) is arranged and adapted to particles of biomass ( 1 ) passing through the openings ( 35 ) into one under the opening ( 34 ) arranged dosing device ( 36 ) to allow. Pelleting press ( 3 ) according to claim 2, characterized in that between the distribution cone ( 31 ) and the distribution ring ( 34 ) a scraper arrangement ( 32 ) is arranged, with at least one scraper ( 33 ), which extends in the radial direction at least over a part of the distribution ring ( 34 ), further provided with drive means for guiding the scraper arrangement ( 32 ), so that the at least one scraper ( 33 ) via the distributor ring ( 34 ) strips. Pelleting press ( 3 ) according to claim 2 or 3, characterized in that the openings ( 35 ) are closable. Pelleting press ( 3 ) according to one of the preceding claims, characterized in that within a respective metering device ( 36 ) a roller assembly having a plurality of rollers ( 38 ) is arranged for dosing the biomass ( 1 ). Pelleting press ( 3 ) according to claim 5, characterized in that the rollers ( 38 ) are further configured and configured to store the biomass ( 1 ) and / or dissolve. Pelleting press ( 3 ) according to claim 5, characterized in that the rollers ( 38 ) may be formed as spoke rollers, as knife rollers or as rollers, on the peripheral surfaces in regular patterns projections and / or depressions, in particular in diamond shape, are formed. Pelleting press ( 3 ) according to one of claims 5 to 7, characterized in that above the roller arrangement in the metering device ( 36 ) a memory space ( 37 ) is adapted to biomass ( 1 ) through an opening ( 35 ), the dosing device ( 36 ), record and temporarily store. Pelleting press ( 3 ) according to one of the preceding claims, characterized in that the chutes ( 40 ) each have an outlet opening ( 45 ) from a lower outlet edge ( 46 ) is limited. Pelleting press ( 3 ) according to claim 9, characterized in that the lower outlet edge ( 46 ) at a height (h) above the flat die ( 4 ), wherein the height (h) is less than 2 times, preferably less than 1.5 times, more preferably less than 1.0 times the press nip height. Pelleting press ( 3 ) according to claim 10, characterized in that the height h = 0. Pelleting press ( 3 ) according to one of claims 9 to 11, characterized in that the lower outlet edge ( 46 ) is arranged so that it lies in an area between the press nip, which between the associated roller ( 5 ) and the flat die ( 4 ) is formed, and a vertical (S), which the associated roller ( 5 ). Pelleting press ( 3 ) according to one of claims 9 to 12, characterized in that the chutes ( 40 ) each have a first chute section ( 41 ) and a second chute section ( 42 ), wherein the second chute section ( 42 ) on its of the associated roller ( 5 ) facing away by an arcuately curved wall ( 43 ), the lower outlet edge ( 46 ) through a lower end of the second chute section ( 42 ) is defined. Pelleting press ( 3 ) according to claim 13, characterized in that the second chute section ( 42 ) on its associated roller ( 5 ) side facing by an arcuately curved wall ( 44 ) is limited so that a horizontal cross section of the lower Fall shaft section ( 42 ) in the direction of the particle of the biomass ( 1 ) rejuvenated. Pelleting press ( 3 ) according to claim 13 or 14, characterized in that the arcuately curved wall ( 43 ) in the area of the lower outlet edge ( 43 ) is curved so that a tangent (T) to the curved wall ( 43 ) in the area of the lower outlet edge ( 43 ) an angle α with the rolling surface ( 19 ) of the flat die ( 4 ), wherein the angle α between 20 ° and 55 °, preferably between 30 ° and 45 °, more preferably between 32 ° and 40 °. Pelleting press ( 3 ) according to claim 15, characterized in that the chutes ( 40 ) have a height and an angle α, which are dimensioned such that the from the respective outlet opening ( 45 ) exiting particles of biomass ( 1 ) have a velocity component in the horizontal direction which on average assumes a value which lies in a range between 80% and 120%, preferably between 90% and 110%, in particular approximately 100% of the speed of the rolling surface ( 19 ) lies. Pelleting press ( 3 ) according to any one of the preceding claims, characterized in that further means are provided for closing the manholes ( 40 ) and / or the distributor device, in particular the distributor cone ( 31 ) and / or the distribution ring ( 34 ) to vibrate. Process for the production of pellets ( 10 ) from material to be pressed, preferably from biomass ( 1 ) for use as fuel in fireplaces, the biomass ( 1 ) consists of cellulose and / or lignocellulosic fibers, shavings or chips, the pelleting press ( 3 ) a flat die ( 4 ) and a plurality of on the flat die ( 4 ) rolling rolls ( 5 ), in which the biomass ( 1 ) through in the flat die ( 4 ) drilled holes ( 13 ) to pellets ( 10 ), characterized in that the biomass ( 1 ) via a distributor on the number of rollers ( 5 ) and in each case a metering device ( 36 ), the dosing device ( 36 ) the biomass ( 1 ) metered into a chute ( 40 ) and the biomass ( 1 ) in the chute ( 40 ) on an area of the flat die ( 4 ) is fed in the direction of movement ( 47 ) of the flat die ( 4 ) in front of the relevant roller ( 5 ) lies. Method according to claim 18, characterized in that the biomass ( 10 ) through the metering device ( 36 ) in a space ( 37 ) is cached. Method according to claim 18, characterized in that the biomass ( 1 ) with a velocity component in the horizontal direction from the chute ( 40 ) of the flat die ( 4 ), which on average assumes a value which lies in a range between 80% and 120%, preferably between 90% and 110%, in particular approximately 100%, of the speed of the rolling surface ( 19 ) lies.

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