EP1479511A2 - Method of manufacturing compression moulded articles - Google Patents

Abstract

The method involves filling a pressing mould (4) with pressed material (12) such as lignocellulose material and compacting the material into blanks in the pressing chamber of a stage press (1) through rams (7) which project into the numerous openings of the mould. After compacting, the mould is lifted with the pressing bar (3) and raised additionally against the bar so that the finished blanks are ejected from the mould and then from the pressing chamber into a container. Independent claim describes pressing machine and stage press with a lowering and lifting device at the edge.

Description

The invention relates to a method for producing compacts according to the preamble of claim 1, to a system according to claim 23 and a deck press for the system.

DE 199 55 844 A1, from which the invention is based, relates to a method and a press for making pellets. After that there are pellets for Heating purposes from pressed biomass, such as sawdust and / or from Wood chips, the raw material also being grain and corn ground form or starch in the amount of 1 to 10 weight percent May contain, which is added to the mixture as a lubricant and binder. The associated press is available as a ring or flat die press Rollers that roll the material to be pressed in a circle through the openings of a die press and create pellets or pellets.

Such wood pellets have a diameter of 4 to 10 mm and are shorter than 50 mm. Wooden briquettes have different shapes, the diameter being larger than 20 mm. Both are compacts with a density greater than 1000 kg / m ^3, preferably greater than 1200 kg / m ³ . They are used for firing in fireplaces, special incinerators and other fireplaces and are suitable for automated firing because of their free-flowing properties. The pressed material for the production of the compacts can also be produced from materials containing lignocellulose other than wood, such as annual plants (for example straw, bagasse, ..), palm trees, peat or certain types of lignite or from mixtures of different materials containing lignocellulose. For the disposal of plastic (e.g. thermoset) such waste can be mixed with the lignocelullose material 5% to 50%. To do this, however, the exhaust gases during combustion must be specially filtered. Pellet and wood briquette production is generally based on shredded materials in the form of chips.

According to DE 26 00 648 C2 and US Pat. No. 3,743,462, the material to be pressed is pressed with rollers through a perforated die. In wood briquetting, extrusion presses are generally used, in which the chips are pressed into a forming channel with a stamp. Pellet and extrusion presses have the disadvantage that the capacity per machine is up to 3t / h. is limited. When pelleting, an adhesive such as starch with an amount of up to 2%, based on the dry wood mass, often has to be added, since the compression achieved to 1,300 kg / m ^{3 is} not sufficient to achieve sufficient strength without a binder , Furthermore, the electrical power consumption is relatively large and uneconomical. Theoretically, normal flat pressed plates can also be manufactured on continuous double belt presses or single and multi-day presses and used as fuel. But when splitting the flat pressed panels with saws, sawdust is produced, whereby the minimum kerf width is approx. 3 mm. The compact is therefore not round and therefore relatively unsuitable for automated firing. Furthermore, 15% sawdust is produced on a 10 mm thick compact. Precise cutting of the compact at high density is also difficult.

The invention has for its object to provide a method and a system with large capacity for the production of round compacts, which do not have to be divided after pressing and have a density of up to 1500 kg / m ³ .

The solution to this problem is according to claim 1 that the filling a press mold with material to be pressed and the compression of the material to be pressed Pressings in the press room of a multi-stage press with one in many openings The plunger is immersed in the mold and that after compression the Press form raised with the press bear and additionally against the press bear starts up, the finished compacts are ejected from the mold and then from the press room into a container by means of a Ejection device can be pushed out.

A second solution according to claim 3 is that the compression of the Pressed goods for pellets in the press room of a multi-level press with in many Plunger plunging openings of a press mold filled with material to be pressed after compression, the plunger with the press bear comes out of the mold drive up, and the mold is moved out of the press room, the finished compacts are pressed out of the openings and after the Refill the mold for the next compression cycle in the Press room is retracted.

A system for performing the method according to claim 23 a filling device and a stack press, between which a filling and Extension device for the mold is arranged, the mold many Has openings for receiving the material to be pressed and the deck press Press frame with press table arranged in it and by means of hydraulic Cylinder piston assemblies can be raised and lowered press bear and on Pressbear ram for all openings of the mold are attached.

According to the method according to the invention, shredded material, usually containing lignocellulose, is introduced into a plate-shaped press mold with openings or bores, the bores corresponding to the diameter of the compact and being arranged perpendicular to the surface of the press mold and being completely drilled through. The mold can be made of metal and has about the thickness that results from the bulk density of the material and the length and density of the compacts. For example, for wood chips with a bulk density of 250 kg / m ³ and a compact length of 30 mm, the thickness of the mold is 140 mm. The chips scattered into the mold are compacted in a clockwise working flat press with many plungers and after the mold has been moved out of the press, the compacts are pressed out of the mold. Before or during compaction, steam can be introduced into the bores from one side, preferably from below, in order to heat and moisten the compacts.

The lignocellulosic material can be of different moisture and shape to be delivered. As a rule, material that is too large is used Dimensions first crushing with a suitable aggregate (Mill, refiner, snails, chipper, etc.). Comminution is preferred so that 95% of all particles pass through a sieve with mesh sizes of 1.5 mm would fall through.

In the case of using forest wood, palm trees, peat, lignite or from Annual plants such as straw can be damp depending on the time of harvest and after Storage period from harvest or breakdown between 8 and 200% vary. If already used lignocellulosic material like Recycled wood or waste paper is used, the moisture is usually less than 20%, often only 5%. In order to carry out the process economically, reprocessing separately according to the humidity is recommended perform. When much of the lignocellulosic material is over moisture 120%, drying or predrying can be carried out or drying takes place only in the compact form.

According to the invention there are three examples or different possibilities the humidity and temperature before and during the production of the compacts to control, the choice of the method by the moisture on delivery in Factory and according to the pelletizability of the material to be processed got to.

A. Use of dried material and pressing at over 90 ° C:

In the case of using lignocellulosic material with different Moisture of 5% - 180% is over with lignocellulosic material with moisture 20% initially drying the material to moisture below 20%, preferably to 10%. Drum or are used for example Current dryer.

The material that has been dried in the factory and that has already been delivered dry now before placing it in the mold in a mixer or another Steamed container. Steaming has several functions. For one thing the temperature of the particles raised to 80 ° C and higher. On the other hand the vapor condenses on the particle surface, causing humidification brings itself. This is particularly important for particles that have a moisture content below 5% exhibit. In the case of using particles that have a wax layer on them the surface - like straw - becomes the wax layer through the steam soft and then dissolves even at low mechanical friction from the surface, reducing the stickiness is increased. If starch is added to the particles, the starch swells the condensed water of the steam and later has a stronger effect adhesive. The increase in moisture due to steaming is depending on the amount of Heating of the particles between 2% - 5%.

After sprinkling the material into the mold, it can be compacted and be pressed. The process must be carried out in such a way that the Particles are later sufficiently glued, if possible without the addition of adhesive. This is achieved with lignocellulose particles by the fact that a Temperature greater than 90 ° C in combination with a humidity above 5% during of compression is present. Then the lignin and the soften Hemicellulose and become sticky. The particles can due to the Form softening very close contact surfaces. So can among other things Hydrogen bonds form. It has therefore also proven to be advantageous proven, especially if there was no pre-steaming or the temperature from pre-steaming to compacting has dropped too quickly that steam is introduced into the bores of the mold during the compression becomes. If steam is introduced during compression, the Floor press can be heated. In addition, it is beneficial to have a preheated one Use mold to condense the steam on the mold too avoid. For example, the mold can be filled by contact before filling be preheated with a hot plate.

In this case, it is imperative that at the start of compaction a temperature above 90 ° C and a humidity above 5% at the Particle surface is present, resulting in a good bond with little Press pressure result. Furthermore, substances that are difficult to pellet, such as Straw pressed. It is also convenient to target a mix of Example of difficult to pelletize material such as straw and easily pelletizable Press material like lignite. The temperature will rise to over 90 ° C by pre-steaming to a sufficiently high temperature a subsequent cooling to 90 ° C and / or by introducing steam set during compression.

B. Use of dried material and pressing Room temperature 10 - 50 ° C:

In a further embodiment of the invention, the Particle surface temperature during compaction below 90 ° C - preferably be room temperature. The moisture of the particles before Spreading must be less than 20%. In this case, however, binders or agglomeration aids for the particles such as hydrated lime, Starch, gypsum, resins of the jaw, etc. are added. The press pressure is significantly larger. Evaporation before spreading can also be done in this case be advantageous if, for example, starch is used. The mold and the press plates are not heated, so the plant technology is very is simple. The system can be run without any heating,

C. Use of moist material or only pre-dried material and hot pressing

If a large part of the lignocellulose material with moisture over 20% can be delivered to the factory without separate drying of the particles compression is carried out. This is done by drying the particles in the Mold carried out before and or during compaction. A Predamping before scattering can also be used to activate binders be performed. The particles are dried in the mold preferably by introducing hot air into the bores of the mold. The drying can also be done by simply heating the particles in the Press mold at over 100 ° C. To do this, the mold must be placed in front of the Scatter a temperature above 100 ° C, preferably above 150 ° C.

As a special embodiment of this variant, particles with moisture can over 120% of the water is first squeezed mechanically, so that the particles have a moisture of 30 - 40% before further drying exhibit. To do this, steam is first used (saturated steam or superheated steam) at a temperature of 100 - 200 ° C, then compressed or Squeezed out water and then by introducing hot air or just over Conduction dried further and finally compressed to final density. This enables a significantly better thermal energy balance to be achieved become.

• Streuen in eine Pressform mit einer Temperatur über 100 °C, Beschickung der beheizten Etagenpresse mit dieser beheizten Pressform (Beheizung des Presstisches und Pressbärs auf 100 - 270 °C)
• Eventuell Einleitung vor oder zu Beginn der Verpressung von heißer Luft oder klimatisierter heißer Luft in die Öffnungen der Pressform und nachfolgend
• eine so lange Verpressung, dass die Presslinge nach der Pressung eine Feuchte geringer 15 % bevorzugt 6 % aufweisen, dabei muss der Schließvorgang entsprechend der Entfeuchtung der Presslinge gesteuert werden. Es empfiehlt sich vor Erreichung der Sollrohdichte der Presslinge, also vor der endgültigen Verdichtung, die Trocknung abzuschließen. Der Vorteil dieser Methode liegt darin, dass kein oder nur sehr wenig Bindemittel verwendet werden muss und dass ein separater Trockner nicht nötig ist.

The process flow for example C in key words now consists of

• Spread in a press mold with a temperature above 100 ° C, load the heated multi-stage press with this heated press mold (heating the press table and press bar to 100 - 270 ° C)
• Possibly introduction before or at the beginning of the pressing of hot air or conditioned hot air into the openings of the mold and afterwards
• pressing so long that after the pressing the compacts have a moisture of less than 15%, preferably 6%, the closing process must be controlled according to the dehumidification of the compacts. It is advisable to complete the drying before the target density of the compacts is reached, i.e. before the final compaction. The advantage of this method is that no or very little binder has to be used and that a separate dryer is not necessary.

As a result, according to the inventive method in a Stack press (length 20 m, width 2 m) about 50 t / h pellets in one Diameter of 8 mm and a length of 50 mm with a cycle time of 1 Pressing per minute are generated. This means an enormous technical progress over the known state of the art.

Further advantages of this procedure are:
Since a higher pressing pressure can be used, the pellet density can be set higher. This also leads to better abrasion resistance of the pellet and better fire behavior. Less or no adhesive has to be used as the density of the pellets increases. With the possibility to set an optimal combination of moisture and temperature in the particles during the pressing and to determine the dwell time for the temperature and moisture exposure according to the desired properties, the use of adhesive can also be minimized and the abrasion resistance of the pellets is increased. It can also be used to pelletize lignocellulosic materials such as straw that are difficult to pelletize.

While the length of the well-known pellet presses and extrusion presses the press length cannot be set in a defined manner, there is a Production according to the invention the possibility of pressing compacts with exact To produce dimensions in length, the shape of which is particularly suitable for the combustion can advantageously be determined.

Further advantageous measures and refinements of the subject of Invention emerge from the subclaims and the following description with the drawing.

Figur 1

die Anlage und Etagenpresse nach der Erfindung in einer Seitenansicht und im Schnitt die mit Pressgut gefüllte Pressform,

Figur 2

die Etagenpresse nach Figur 1 während des Verdichtens des Pressgutes,

Figur 3

die Etagenpresse nach Figur 2 mit Senk- und Anhebevorrichtung für die Pressform,

Figur 4

die Etagenpresse nach Figur 3 mit angehobener Pressform und ausgestoßen Presslingen und

Figur 5

die Anlage nach Figur 1 mit zwei Pressformen.

Show it:

Figure 1

the plant and deck press according to the invention in a side view and in section the press mold filled with material to be pressed,

Figure 2

the deck press according to FIG. 1 during the compression of the pressed material,

Figure 3

the deck press according to FIG. 2 with lowering and lifting device for the press mold,

Figure 4

the deck press according to Figure 3 with raised mold and ejected compacts and

Figure 5

the system of Figure 1 with two molds.

The drawing shows with Figures 1 to 5 three systems for performing the Method according to the invention. Figures 1, 2 and 5 show the system for Filling the mold 4 or the molds 4 and 4 'with material to be pressed 12 outside the deck press 1 with the filling device 9, while after the Figures 3 and 4 a filling of the openings 11 of the mold 4 with 12 to be pressed is provided within the press room 18. The mold 4 or the Press molds 4 and 4 'are with an entry and exit device (not shown) in the press room 18 and on the table 17 retractable and extendable executed, the system of Figure 5 with two movable together Molds 4 and 4 'is equipped. Then once in front of the Stack press 1 the compacts 10 with the pressing device 19 already while moving out of the press room 18 in rows (via the Width) pressed into a container and then with the Filling device 9 fills the openings 11 with material to be pressed 12. At the next The compression cycle, on the other hand, is done by pressing and filling to the right of the Floor press 1. For the sake of simplicity, the mirror image is identical Formation of squeezing and filling not to the right of the level press 1 shown. The squeezing with the squeezing device 19 can either mechanically with plungers or with compressed air or vacuum. When the system is designed with two molds 4 and 4 'according to FIG the greatest advantage that the output of compacts 10 per unit of time is much higher.

The floor press 1 for the plant for carrying out the method exists from a press frame (not shown) with arranged therein Press table 2 and by means of hydraulic pressure cylinders 6 and Press plunger 5 press bar 3, which can be raised and lowered, and the one on press bar 3 in the same number as the openings 11 in the mold 4 Ram 7.

Figures 1 and 2 still show the attachment of leads 13 from Channels 15 of the press table 2 to the openings 11 on each long side of the Press mold 4, in steam and / or vacuum to press mold 4. to Forwarding of steam or vacuum in the openings 11 between the On the long sides there is a sieve 8 between the press table 2 and the press mold 4 appropriate. As FIG. 4 further shows, the mold 4 is after the Compacting by means of a lowering and lifting device 14 when opening the Stack press 1 additionally raised to the press bear 3 and the Ejected compacts 10 with the tappets 7 on the press table 2. Then the compacts 10 are pushed into the Container 16 pushed out.

LIST OF REFERENCE NUMBERS

1.

floor Press

Second

press table

Third

Press stamp, press bear

4th

Press mold (4 '= 2nd press mold)

5th

Press plunger

6th

Press pressure cylinders

7th

tappet

8th.

scree

9th

filling device

10th

Pellet, pellet

11th

Openings, holes

12th

pressed material

13th

supply

14th

Lowering and lifting device

15th

channels

16th

container

17th

table

18th

Press room

19th

squeezing

20th

Pusher

Claims (29)

Method for producing compacts from comminuted pressed material (12), such as lignocellulosic material and / or other combustible material for firing in fireplaces, the pressed material (12) being introduced into openings (11) in a press mold (4) and compacted therein to form compacts (10) is characterized in that the filling of a press mold (4) with pressed material (12) and the compression of the pressed material (12) into pressed parts (10) in the press space (18) of a multi-stage press (1) with in many openings (11) of a press mold (4) plunging plunger (7) takes place, and that after compression, the press mold (4) with the press bear (3) is raised and additionally drives up against the press bear, thereby ejecting the finished compacts (10) from the press mold (4) and then are pushed out of the press space (18) into a container (16) by means of an ejection device. A method according to claim 1, characterized in that the openings (11) of the press mold (4) outside the deck press (1) are filled with press material (12) and then the press mold (4) is moved into the press chamber (18). A process for the preparation of compacts of comminuted material to be pressed, such as lignocellulosic material and / or other combustible material for firing in fireplaces, where the pressed material (12) is introduced into openings (11) of a mold (4) and compressed therein to pressings (10), characterized characterized in that the compression of the pressed material (12) into pressed parts (10) takes place in the press chamber (18) of a multi-stage press (1) with plungers (7) immersing in many openings (11) of a press mold (4) filled with pressed material (12), After compaction, push the plunger (7) with the press bear (3) out of the press mold (4) and the press mold (4) is moved out of the press chamber (18), the finished compacts (10) are pressed out of the openings (11) and after refilling, the press mold (4) is moved into the press chamber (18) for the next compression cycle. Method according to claims 1 to 3, characterized in that the compression of the pressed material (12) in the deck press (1) on the one hand and the pressing of the pressed parts (10) and the refilling on the other hand takes place simultaneously in two molds (4, 4 '). Method according to claim 3, characterized in that after the pressing mold (4) has been moved out of the press space (18), the pressed articles (10) are removed from the openings in rows by means of a pressing device (19) and are subsequently refilled with pressed material (12). Method according to one or more of claims 1 to 5, characterized in that the starting material for the material to be pressed (12) is comminuted in such a way that approximately 95% of the particles would fall through a sieve with a mesh size of 1.5 mm. Method according to one or more of claims 1 to 6, characterized in that, in a mixer, binder or other adhesive substances are added to the particles before they are filled into the mold (4). Method according to one or more of claims 1 to 7, characterized in that the filling of the material to be pressed (12) into the mold (4) takes place from above, with leads (13) from below into the openings (11) of the mold (4 ) a vacuum is applied. Method according to one or more of claims 1 to 8, characterized in that steam is introduced from below into the openings (11) of the press mold (4) during the compression, if appropriate with the interposition of a sieve (8). Method according to one or more of claims 1 to 9, characterized by drying the compacts (10) to a moisture level below 12% in a dryer. Method according to Claim 6, characterized in that the starting material for the pressed material (12) is comminuted in mills, refiners or in twin-screw fiberizers. Method according to one or more of claims 1 to 11, characterized by the treatment of the starting material according to example "A", according to which the material to be pressed (12) before compression for scattering by steaming to a moisture content of less than 20%, preferably 10%, but greater than 5 Weight percent and is set to a temperature greater than 90 ° C and the compression takes place in a heated press mold (4). A method according to claim 12, characterized in that the evaporation of the starting material takes place in a mixer. Method according to claims 12 and 13, characterized in that when using starting material with a moisture content above 20%, drying to moisture levels below 20%, preferably 10%, is carried out in a drum or current dryer. Method according to claims 12 to 14, characterized in that the press mold (4) is preheated before the filling of the pressed material (12). Method according to claims 12 to 15, characterized in that steam is introduced into the openings (11) of the press mold (4) during or at the start of the compression. Method according to one or more of claims 1 to 11, characterized by the treatment of the starting material according to example "B", according to which a small amount of a binder and / or agglomerating agent is added to the dried starting material with a moisture content below 20%, the pressed material thus prepared ( 12) is sprinkled into the openings (11) of an unheated mold (4) and the compression takes place in an unheated multi-stage press (1) at high pressure. A method according to claim 17, characterized in that the compression takes place at a temperature of 10 ° C to 50 ° C. Process according to claims 17 and 18, characterized in that the starting material is steamed in a mixer before the spreading. Method according to one or more of claims 1 to 11, characterized by the treatment of the starting material according to example "C", after which the moist or pre-dried pressed material (12) is sprinkled into a press mold (4) heated to 100 ° C and in a heated multi-stage press ( 1) is compressed, the press bear (3) and press table (2) are heated to 100 ° C to 270 ° C, hot or conditioned hot air from 100 ° C to 200 ° C into the openings (11 ) the mold (4) is introduced and the compression ends when the compacts (10) have a moisture content of less than 15%, preferably 6%. A method according to claim 20, characterized in that when using a starting material with a moisture content of over 120% is mechanically squeezed out before the dispersion to a moisture content of 30% to 60%. Process according to claims 20 and 21, characterized in that the mold (4) is heated to a temperature of over 150 ° C before the material (12) is sprinkled in. Plant for performing the method according to claims 1 to 22, consisting of a filling device (9) and a deck press (1), between which an entry and exit device for a Press mold (4) is arranged, the press mold (4) many openings (11) for receiving the pressed material (12) and the deck press (1) from press frame with press table (2) and arranged therein by means of hydraulic cylinder piston arrangements (5, 6) lowerable press bear (3) and on the press bear (3) plunger (7) for all openings (11) of the mold (4) are made. Stack press for the system according to claim 23, characterized in that a lowering and lifting device (14) for the press mold (4) to the press bear is provided on the edge of the press bear (3). Stack press according to claims 23 and 24, characterized in that a supply line (13) is arranged for connecting a vacuum device or for supplying steam to the press mold (4) to each opening (11). Stack press according to claims 23 to 25, characterized in that the diameters of the feed lines (13) and the openings (11) are approximately the same size. Stack press according to claims 23 to 26, characterized in that a screen (8) is provided between the press mold (4) and the press table (2). Stack press according to one or more of claims 23 to 27, characterized in that the press mold (4) has a thickness of approximately 150 mm and the openings (11) have a diameter of 4 to 12 mm. Plant according to Claim 23, characterized in that two press molds (4 and 4 ') are provided, the removal of the pressed articles (10) from the openings (11) and their refilling with pressed material (12) in alternating operation, once on the left and once on the right Floor press (1) is to be carried out.

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