NL1007887C2 - Granulating manure by pressing it through a rotating perforated surface, preferably a drum, to form fertiliser granules - uses pressing device rolled over perforated surface and manure - Google Patents

Abstract

A process for granulating manure comprises the use of a pressing device to force the manure through a rotating perforated surface. The pressing device is rolled over the perforated surface and the manure in between the device and surface. Also claimed is the process apparatus.

Description

Short indication: Method and device for granulating manure

The invention relates to a method for granulating manure according to the introductory part of claim 1. The invention also relates to a device for granulating manure according to the introductory part of claim 12.

Such a device and such a method are known from European patent 0 303 755. In this patent it is proposed to granulate manure by rotating a rotor located eccentrically with respect to a circular arc-shaped wall with a perforated circular arc section. The rotor is equipped with radially reciprocating wings that are pressed out by spring pressure and that scrape along the circular arc-shaped wall during operation, thus transporting manure between the rotor and the wall.

Thus, in this device, which operates on the principle of a wing cell pump, manure which is carried between two wings in the circumferential direction in a circumferential direction is compressed between the rotor and the circular arc-shaped wall and is therefore pressed out through the perforations in the wall. .

A drawback of this pump is that it is heavily loaded and therefore has to be dimensioned very heavily and that the granulation takes a lot of energy, at least if the built-up pressure is sufficient to produce sufficiently stable granules. Furthermore, the rotor with the wings forms a fragile, complicated construction that is subject to heavy wear, especially if the manure contains a lot of sand and crushed stone, as is the case, for example, with chicken manure originating from free-range or aviary houses. The granulate obtained in the proposed manner is highly compressed, which is not detrimental to the rapid release of plant nutrients contained therein if the granulate is used as fertilizer to promote plant salutation.

The object of the invention is to enable granulation of manure at a lower cost and with a lower energy consumption and to provide a granulate from which plant nutrients are released more quickly.

This object is achieved according to the present invention by carrying out a method for granulating manure according to the characterizing part of claim 1. The invention also provides for the same purpose a device according to the characterizing part of claim 12.

Because the push-through assembly in operation rolls over manure between the perforated surface and the push-through assembly 10, shearing deformation of the manure during granulation of the manure remains small and the original material structure of the manure remains largely intact. . More particularly, shearing deformation of the manure remains mainly limited to areas where the manure is broken for granulation. As a result, a gentle compression of the manure is sufficient to obtain sufficiently stable granules. When breaking, very few fine grains are released. These fine grains are also largely rolled back together and 20 other fertilizer parts, so that very little fertilizer is lost.

Because the manure is little compressed and more porous, it absorbs water faster after spreading and falls apart faster. Moreover, because the manure is less concentrated, it is better to spread it evenly distributed and there is less danger of burning crops at the location of any local accumulations of scattered manure. If the granules are used to prepare a fertilizer slurry, it is advantageous that they disintegrate faster in water than highly compressed granules.

Because the manure is processed at relatively low pressures and is deformed relatively little, the energy consumption when using the method and the device according to the present invention is very low. Furthermore, a light construction is sufficient for the construction of the device.

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Unlike conventional granulated manure, in a manure granulate obtained using the method and apparatus of the present invention, the specific gravity is generally about equal to the specific gravity of the starting manure.

Particularly advantageous embodiments and embodiments of the invention are described in the dependent claims. Further objects, effects, advantages and details regarding the present invention will become apparent from the following description, with reference to the drawing.

In the drawing: Fig. 1 shows a schematic overview of a device according to the invention.

Fig. 2 shows a more detailed representation of a perforated surface and a push-through assembly of a device according to the exemplary embodiment shown in Fig. 1.

The apparatus shown in the figures and the method of carrying out the method 20 described in connection therewith are the most preferred embodiments of the invention at present.

The device shown in Fig. 1 is composed of a processing line, the beginning of which is formed by a receiving hopper 1, into which manure can be dumped. The manure that is processed is preferably chicken manure or other poultry manure, which is preferably dried to a dry matter content of more than 70% and preferably between 75 to 80 and 90 to 95%. Such manure is obtained, for example, in battery cages in which the manure is dried using heat released by the animals. In principle, it is also possible to process manure from other animals which, depending on the consistency of the manure, may or may not be dried, mixed with additives or otherwise prepared.

A conveyor belt, indicated by an arrow 2., extends from the receiving hopper 1 to a conveyor belt represented by an arrow 3. The chute ^ 1007887-4-3 communicates with an extraction line represented by an arrow 4 with an extraction unit 5 which is provided with a collection container for collecting extracted material, which mainly consists of dust and springs. The extracted material contains very little manure, so that it can be dumped at waste dumps without special disadvantages. Furthermore, the extracted material can also be properly processed in a waste incineration plant1.

The chute 3 ends above a conveyor belt 6.

A suction mouth 7 is arranged along the conveyor belt 6, which also communicates with the suction unit 5 via a discharge channel, which is represented by an arrow 8. When dust falls on the conveyor belt 6, the manure becomes loose and feathers that have come loose during the belt passing the manure 15 over the conveyor belt 6 is extracted via the suction mouth 7 and thus separated from the manure. The conveyor belt 6 ends above a buffer storage 9, in which manure can be stored until sufficient manure has been collected to enable the downstream parts of the device to operate for a sufficiently long time.

A conveyor belt connects to the conveyor belt 6, along which a further suction mouth 10 is located, which communicates with the suction unit 5 via a discharge channel 11, so that even more dust and feathers are separated from manure passing in free fall. The fact that the buffer storage 9 is located downstream of provisions for separating manure on the one hand and non-manure components, such as dust and feathers on the other, offers the advantage that a smaller buffer storage is sufficient. In addition, the separation, which is not very sensitive to repeated start-up and stopping, can be carried out at a relatively low speed, which is advantageous for achieving high effectiveness with a small installation. Another advantage of the off-line pre-separation is that a relatively small extraction unit can suffice, because these are not simultaneously for pre-separation and for the separation in the area of the granulation- facilities need to be deployed.

From the buffer storage 9 a further elevator belt, represented by an arrow 12, runs upwards above a pair of rollers 13. From the elevator belt 13, the manure pours into the gap between the rollers, where the manure is rolled to a size which corresponds to the gap or the contact force between the rollers. When the manure is passed through the gap between the two rollers 13, whereby passing manure is compressed, a light kneading operation is carried out, which is advantageous for the loosening of springs and for making the smoother and more homogeneous material structure1, which limits the breaking of small parts from dumpling dumplings during subsequent operations. Drive motors which are not shown are provided for driving the rollers 15.

Incidentally, other structures with circumferential surfaces, such as conveyor belts, can be used instead of the rollers.

Along a dumping track (arrow 16) under the rollers 13 there is a next suction mouth 14, which communicates with the suction unit 5 via an extraction channel, which is shown as an arrow 15. When the dung dumplings are crushed between the rollers 13 material that has come loose is effectively separated from the manure 25 by the air movement generated via the suction mouth 14.

The pouring track 16 connecting to the rollers 13 leads to an inner space of a drum 17 with a perforated peripheral surface 18. The drum 17 is shown cutaway in Fig. 1 and shown in more detail in Fig. 2.

A push-through assembly 19 is movable along the perforated surface 18. The push-through assembly 19 is rotatable about a pivot axis 20 and pivotable about a centerline 21 of the drum 17. To this end, the push-through assembly 19 comprises a drum 22 and rocking arms 23 pivotable about the centerline 21 of the drum 35 to be. The rocking arms 23 of the push-through assembly 19 are coupled to a drive 24 for driving movements of the push-through assembly 19. The drive 24 is composed, inter alia, of a drive wheel 25 and a connecting rods 26 between the driving wheel 25 and the rocking arms 23 of the push-through assembly 19. When the driving wheel 25 is rotated, the rocking arms 23 are pivoted about the axis 21 of the drum 17 in a path which is indicated by a double arrow 27.

Thus, the rotary axis 20 of the push-through assembly 19 is movable substantially parallel to the perforated surface 18. In operation, the push-through assembly 19 rolls along the perforated surface 18 and over manure between the perforated surface 18 and the push-through assembly 19.

During unrolling over the manure, the push-through assembly 19 pushes manure through perforations of the drum 17, so that the manure is reduced to granules. In addition, shearing deformation of the manure outside areas where the manure is broken remains limited and the original material structure of the manure remains largely intact. As a result, a light compression of the manure is sufficient to obtain sufficiently stable granules. When breaking, very few fine grains are released. Moreover, these fine grains are largely rolled back together and other manure parts, so that very little manure is lost.

Because the manure is less compressed and more porous than conventional granulated manure, it absorbs water more quickly after being spread, falls apart faster when wetted, it is better distributed evenly distributed and there is less danger of burning crops. location of any local accumulation of scattered manure.

A relatively low pressure is sufficient for pressing the manure through the perforated surface 18, while the plastic deformation of the manure remains limited. The energy consumption is therefore very low. In experiments with a prototype that has not yet been optimized, a energy consumption of 21 kWh per tonne of granulate has already been achieved, including the energy involved in transporting manure through the installation and driving the extraction unit 5 This is approximately 1/8 of the energy consumption of a known pelletizer for granulating manure. Furthermore, a light construction already proved to be sufficiently strong and rigid to generate the required powers and to withstand the occurring forces.

The peripheral surface 22 of the push-through assembly 19 is of a profiled design. This prevents sliding of the peripheral surface over the manure. Furthermore, manure between the circumferential surface 22 of the push-through assembly 19 and the circumferential surface 18 of the drum 17 is only locally pressed against the perforated surface 18, whereby a better granulation and in particular less spread of the granulate size is obtained.

The profiling has edges 28 oriented parallel to the rotary axis 20 of the push-through assembly. As a result, a particularly effective traction is obtained between the manure and the circumferential surface 20 of the push-through assembly.

The profiling of the circumferential surface 22 has a circular outer contour and flanks of the profile elements 28 adjoin sharp edges 29 on the circular outer contour. These sharp edges are conducive to exerting locally highly concentrated shearing forces on the manure, so that it effectively breaks down where the force is applied and the structure of the manure is otherwise little influenced.

Because the push-through assembly 19 is moved back and forth with respect to the perforated surface 18, manure which has not been pushed through the perforations and of which parts which may be too small may have broken off, is repeatedly rolled. As a result, an important part of the broken, too small fragments are rolled back together and other fragments, until these too are pressed in their entirety or in fragments through a passage in the surface (18).

»1007057 -8-

A fan 31 is arranged coaxially with the drum 17 on a front side of the drum 17. On the other end of the drum 17, a suction mouth 32 is arranged, which communicates with the suction unit 5 via an extraction channel (arrow 33). With the aid of this assembly of air movement devices, a powerful air movement in the area of the perforated surface 18 is generated. In use in the region of the perforated surface 18 this separates fine, loose components, such as dust and feathers, which have come loose from the manure during the rolling and moving of the manure in the drum 18 of the manure. At the location of the perforated surface 18, a separation and a granulation are thus obtained simultaneously, wherein losses of fertilizer are very small due to the described rolling effect.

The perforations 30 in the perforated surface, of which only a few are shown schematically in Fig. 2, are preferably designed as round holes with a diameter of 20 to 10 mm for processing chicken manure into garden fertilizer granulate. By using larger perforations, the spread in the size of the granulate granules increases and the loss of manure decreases. The size of the gap b, i.e. the distance between the perforated surface 18 and the co-acting surface 22 of the push-through assembly 19, is preferably about 1-3 mm. The size of the gap between the rollers 13 depends on the desired particle size of the granulate. In general, it preferably lies between the perforation diameter a and the gap size b in 1.

It is noted that, in particular for the perforated surface and the co-acting surface of the push-through assembly, many other embodiments than the shown embodiments are possible. Thus, neither the perforated surface nor the surface of the push-through assembly cooperating therewith need to be circumferential and can each be hollow or convex and thereby be single or double curved or flat. The mating surfaces can each be dimensionally stable or be part of flexible structures such as circumferential belts.

Since the air movement is directed axially through a drum 17 formed by the perforated surface 18, and the push-through assembly operates on the inside of that drum during operation, an extremely effective channeling of the air movement and thus a very uniform separating effect operation with a limited classification effect in the drum 18.

The perforated surface 18 is furthermore not only designed as a circumferential surface, but moreover also movable in the circumferential direction in the direction indicated by an arrow 34. For driving the circumferential movement of the perforated surface 18, the drive 24 is provided with a belt 35 which runs from the drive wheel 25 to a wheel 36 which cannot rotate relative to the drum 17 and back again.

Since the perforated surface 18 is a circumferential surface that is circulated in an circumferential manner, manure in a certain position is prevented from being crushed again and again in the same position when passing through the push-through assembly 19. By bypassing the Perforated surface 18, other parts of the perforated surface 18 of the drum 17 and of the co-acting unwinding surface 22 of the push-through assembly 19 always come to lie opposite each other, while non-pressed-through manure during the movement of the perforated surface 18 moves relative to that surface.

Since, in the device according to the example shown, the perforated surface 18 is a peripheral surface of a drum 17 with a hollow inner side, the rotary axis 20 of the push-through assembly 19 is oriented parallel to the center line 21 of the drum 17 and to which axis 17 is pivotable, and the push-through assembly 19 is located on the inner side of the circumferential surface 18, the unrolling movability of the push-through assembly 19 is effected in a simple manner. In operation, the push-through assembly 19 always rolls off in a lower section on the inside of the peripheral surface 18 of the drum 17. As a result, manure which has not been pressed through the perforated surface between the press-through assembly 19 and the perforated surface 18 as it passes, always moves along the wall 18 when it is again between the push-through assembly 19 and the perforated surface 18 being rolled into another position by passing.

23. The device of any one of claims 12-22, further comprising a heat source downstream of the perforated surface.

Underneath the drum 17 there is a discharge belt 37 which transports granules that have fallen through the perforations to above a next conveyor belt 38. From the discharge belt 37, the granules deposit along a dumping track (arrow 39). A suction mouth 40 is also situated along this dumping track, which communicates with the suction unit 5 via a suction channel 41. Loose particles, such as dust and feathers, are separated from the fertilizer granules via the suction mouth 40 during granulation. so that a very little dusting and homogeneous product is obtained.

The conveyor belt 33 leads to a heat treatment tunnel 42, in which the granulate is heated to a sufficiently high temperature to kill unwanted germs and insect eggs 25. The fact that the heat treatment is carried out after granulation offers the advantage that the manure is divided into relatively small fragments, so that the manure can be heated relatively quickly to a sufficiently high core temperature. Furthermore, the heat treatment limits the toughness of the manure, which would lead to greater losses prior to granulation during the separation of non-fertilizer components such as dust and feathers and during the rolling and granulation.

The heat source used is a burner 43 with a burner mouth facing a conveyor section 42 located downstream of the perforated surface 18. The heat treatment therefore consists, at least in part, of passing manure through a flame. This offers it

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The advantage that any springs which are so firmly anchored in the manure that they have not been separated from the manure during the previous separating operations are still scorched, which further improves the homogeneity of the granulate 5.

Since the burner mouth 43 is moreover directed into the tunnel 42, a sufficiently strong heating of the granulate granules to the core thereof is achieved in a short time after scorching.

The heat tunnel 42 ends above a shaking screen 44 in which the obtained granulate can be processed if desired into a fine fraction for, for example, agricultural processing (bin 46) and a coarse fraction for use as a garden knife by consumers (bin 45). It should be noted that the number and the manner of carrying out the separating operations may differ depending on the properties of the manure and the desired properties of the granulate. Optionally, another technique can also be used for the separation, such as a fluidized bed. It is also possible herein to agglomerate small fertilizer parts by spraying with a binder. Such techniques are known per se and are therefore not described here in more detail.

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Claims (25)

Method for granulating manure, comprising penetrating manure through a perforated surface (18) by rotating a push-through assembly (19) along that surface, characterized in that the push-through assembly (19) along the perforated surface (18) and is rolled over manure between the perforated surface (18) and the push-through assembly (19). 2. A method according to claim 1, further comprising passing the manure through a gap between two circumferential surfaces, wherein passed manure is compressed. Method according to claim 2, wherein manure is transported through the perforated surface (18) after passing through the slit and before pressing and fine, loose constituents such as dust and feathers are separated from the manure by air movement. A method according to any one of the preceding claims, wherein manure in the region of the perforated surface (19) is separated from the manure by air movement by fine, loose constituents, such as dust and feathers. A method according to claim 4, wherein the perforated surface (18) forms a peripheral surface of a drum (17) with a hollow inner side, the push-through assembly (19) unrolling on the inner side of the peripheral surface 25 and wherein the air movement is substantially is directed axially through the drum (17). The method of any preceding claim, wherein a surface (22) of the push-through assembly (19) is moved back and forth with respect to the perforated surface (18). The method of any preceding claim, wherein the perforated surface (18) is a circumferential surface that is circumferentially moved. A method according to claim 7, wherein the perforated surface (18) forms a peripheral surface of a drum * 1007887 -13- (17) with a hollow interior and wherein a surface of the push-through assembly (19) along an underlying section on the inside of the perforated peripheral surface (18). A method according to any one of the preceding claims, wherein manure, after passing through the perforated surface (18), is subjected to a heat treatment. 10. Method according to claim 9, wherein the heat treatment comprises passing manure through a flame. A method according to any one of the preceding claims, wherein dried bird manure is used with a dry matter content of at least 70% and preferably at least 75 to 80%. An apparatus for granulating manure, comprising a perforated surface (18), a push-through assembly (19) rotatable along said perforated surface (18) and rotatable about a rotary axis (20), and a drive for driving at least the push-through assembly (19), the perforated surface (18) and the push-through assembly (19) delimiting a gap or nip located therebetween, characterized in that the rotary axis (20) of the push-through - assembly (19) is movable substantially parallel to the perforated surface (18) for unrolling a surface (22) of the press-through along the perforated surface and over manure between the perforated surface and the push-through assembly (19) assembly (19). The device of claim 12, wherein the push-through assembly (19) has a profiled peripheral surface (22). The device according to claim 13, wherein said profiling (28) comprises edges parallel to the axis of rotation of (20) the push-through assembly (19). Device according to claim 13 or 14, wherein said profiling (28) has an at least circular arc-shaped outer contour and wherein flanks of profile elements Pi 007887-14 are along sharp edges (29) on said at least circular arcuate outer contour limits. The device of any one of claims 12-15, further comprising at least two rollers (13) opposed to each other upstream of the perforated surface with circumferential surfaces for compressing manure passing therebetween. The apparatus of claim 16, further comprising a conveyor track (16) downstream of said circumferential surfaces and upstream of the perforated surface (18) for conveying manure in a flow direction and an air motion assembly (5, 14, 15) for generating of an air movement in the region of said conveyor track (16). The device of any one of claims 12-17, further comprising an air movement assembly (5, 31, 32, 33) for generating an air movement in the region of the perforated surface (18). 19. Device according to claim 18, wherein the perforated surface (18) forms a peripheral surface of a drum (17) with a centerline (21) and with a hollow inside, the push-through assembly (19) on the inside of the perforated surface (18) is disposed and pivotable about the centerline (21) of said drum (17) and the air motion assembly (5, 31, 32, 33) being adapted to generate a substantially axial through the drum (17) targeted air movement. 20. Device as claimed in any of the claims 12-19, wherein the push-through assembly (19) is hung back and forth between a first position and a second position. The device of any one of claims 12-20, wherein the perforated surface (18) is a circumferential surface that is circumferentially movable, further comprising a drive (25, 35, 36) for driving the circumferential movement of the perforated surface (18). The device of claim 21, wherein the perforated surface (18) is a peripheral surface of a drum with a hollow interior, the pivot axis of the push-through assembly (19). ) is oriented parallel to the centerline (21) of the drum (17) and is pivotable about said centerline (21), and the push-through assembly (19) on the inside of the perforated surface (18) is located. The device of any one of claims 12-22, further comprising a heat source (43) downstream of the perforated surface (18). The device of claim 23, wherein the heat source is a burner (43) with a burner nozzle oriented downstream of the perforated surface (18). The device of claim 24, further comprising a tunnel (42) forming said conveyor section, wherein the burner mouth is directed into the tunnel (42). 0 07 8 87