Process for the production of pelletized bedding

Abstract

The present invention relates to a process for the production of sodium bisulphate-enriched pelletized litter, which is characterized in that crushed litter material is mixed with sodium bisulphate and this mixture is pressed in a die with a pressing ratio of 1:1.5 to 1:5.

Description

[0001] Process for the production of pelletized bedding

[0002] The present invention relates to a process for the production of enriched pelletized bedding which is used as a bedding material in animal husbandry, in particular poultry husbandry.

[0003] The topic of animal welfare is the basis of a general discussion in animal husbandry. In livestock farming, stables are provided with bedding. This has been increasingly enriched with additives to promote animal welfare. These additives should be able to prevent or reduce the formation of harmful substances and thus improve the conditions in the barn.

[0004] DE 20 2023 104 062.4 discloses a pelletized bedding that contains sodium bisulfate as an additive. Sodium bisulphate has proven to be advantageous for reducing ammonia emissions, particularly in poultry farming, and for reducing foot pad and hock joint changes in the animals.

[0005] Pellets made from bedding are usually produced by pressing the bedding material. However, in the production of pelletized bedding, which contains sodium bisulphate as an additive, it has been shown that these cannot be produced using conventional pressing methods. On the contrary, the pressure applied results in significant heat development and the organic components of the pellets containing sodium bisulphate carbonize during the production.

[0006] Therefore, there is a need for a process for the production of pellets from bedding material for animal husbandry, in particular poultry husbandry, which makes it possible to incorporate sodium bisulphate into the pellets without destroying the pellets during the production process. Surprisingly, it has been shown that it is possible to produce pelletized bedding enriched with sodium bisulphate by optimizing the process. The problem underlying the present invention is therefore solved by a process for the production of sodium bisulphate-enriched pelletized bedding, which is characterized in that crushed bedding material is mixed with sodium bisulphate and this mixture is pressed in a matrice with a pressing ratio of 1 : 1.5 to 1 :5.

[0007] It has been shown that it is not possible to produce enriched pelletized bedding with conventional matrices. As soon as enrichment with sodium bisulphate is present, compaction occurs inside the matrices. This causes the temperature inside the matrice to rise and the organic components of the pellets to carbonize. The bedding material enriched with sodium bisulphate can no longer be pressed through the press channels / matrices and production comes to a standstill.

[0008] Surprisingly, it has been shown that at a pressing ratio of 1 : 1.5 to 1 :5, preferably from 1 :2 to 1 :4, especially preferably from 1 :2 to 1 :3, such carbonization does not occur. At a pressing ratio above 1 :5, particularly above 1 :4, charred, black pellets are produced. At a pressing ratio above 1 :3, the pellets are very hard. A pressing ratio of less than 1 :3 is therefore particularly preferred.

[0009] With larger pressing ratios, i.e. pressing ratios above 1 :5 and especially 1 :4, the system and therefore the matrice also becomes clogged. Complex cleaning steps are necessary.

[0010] If the pressing ratio is below 1 : 1.5 or 1 :2, sufficiently stable pellets are not produced. The compression path is then no longer sufficient to compact or compress the material in a suitable manner. According to the invention, the pressing path is the ratio of the hole diameter to the length of the pressing channels (pressing path). With such a pressing ratio, it was surprisingly shown that pelletized bedding enriched with sodium bisulfate can be produced in conventional presses, such as a flat matrice press.

[0011] In a preferred embodiment, the method according to the invention comprises the following steps: a) Providing a bedding material, b) Shredding the bedding material, c) Preparation of the sodium bisulphate, d) homogeneous mixing of the crushed bedding material and the sodium bisulphate, and e) Placing the resulting mixture in a press with a matrice with a pressing ratio of 1 : 1.5 to 1 :5.

[0012] Surprisingly, it has been shown that such a pressing ratio is particularly preferred. The pressing ratio is preferred from 1 :2 to 1 :4, and especially preferred from 1 :2.5 to 1 :3.

[0013] Standard bedding materials can be used as bedding material, which is provided at the beginning. In particular, the bedding material is selected from straw, chopped straw, softwood shavings, lignocellulose, maize silage, rye straw, wheat straw, triticale, spelt, spelt husks, sunflower husks, hay and / or grass. In particular, only one of the aforementioned bedding materials is used to produce pelletized bedding enriched with sodium bisulfate. According to the invention, however, it is also possible for mixtures of 2, 3 or more of the aforementioned materials to be mixed to obtain pelletized bedding from mixtures of different bedding materials.

[0014] For the sodium bisulphate to have an effect that serves to improve animal welfare, the proportion of sodium bisulphate in the pelletized bedding is at least 5% by weight, based on the total weight of the pelletized bedding. For example, if the pelleted litter comprises 100 g, 5 g of this consists of sodium bisulphate and 95 g of the litter material. It is particularly preferable if the proportion of sodium bisulphate in each pellet is the same. For this purpose, it is particularly important that the mixing of the bedding material and the sodium bisulphate in step d) of the method according to the invention is particularly thorough. Surprisingly, it has also been shown that mixing should not take place directly above the press, as homogeneous mixing is then not possible. Furthermore, mixing should not take place at the beginning of a longer conveying section, as segregation can occur during conveying, for example in a screw conveyor. It is therefore part of the professional work to optimize the exact position at which the mixing between the crushed bedding material and bisulphate and the introduction into the matrice of the press takes place, so that a homogeneous mixture is possible, but no segregation occurs.

[0015] Particularly preferably, the proportion of sodium bisulfate in the pelletized bedding is from 5 to 55% by weight, preferably from 6 to 45% by weight, in particular from 7 to 30% by weight, preferably from 8 to 25% by weight and particularly preferably from 10 to 20% by weight, based on the total weight of the pelletized litter. It has been shown that an optimal effect is achieved in these ranges and at the same time a stable pelletized bedding is obtained with the method according to the invention.

[0016] The sodium bisulphate is particularly preferred as it also influences the aw value of the bedding. The aw value (activity of water value) indicates the extent to which water is bound by a substrate, in this case the enriched pelletized bedding. The value is calculated by the ratio of the water vapor partial pressure of a product (p) to the saturation vapor pressure of pure water (p0) according to the formula Cljy — and is given as a unitless value. The addition of a hygro- Po scopic material such as sodium bisulphate increases the proportion of bound water in the bedding. This is relevant for use as it reduces the amount of free water present on the stable floor. Free water is required for numerous microbial processes, such as bacterial growth. At an aw value of less than 0.85, microbial growth and, for example, enzyme activity for converting animal excretion products into gaseous ammonia is significantly reduced. Surprisingly, it has been shown that sodium bisulphate in the preferred proportion ensures that the aw value of a pelletized bedding material produced according to the invention is sufficiently low to reduce the proportion of free water - which is surprising in view of a hygroscopic material.

[0017] Due to the hygroscopic properties of sodium bisulphate, the pelletized bedding material produced according to the invention is packaged at the end of the manufacturing process. In particular, the packaging is airtight, so that no humidity from the air can be absorbed by the pelletized bedding material.

[0018] The diameter of the pellets produced is prefered between 3 and 10 mm, in particular preferred from 4 to 7 mm. Pellets with such a diameter, which is also reflected in the pressing ratio, are particularly preferred in animal breeding, especially poultry breeding.

[0019] The length of the pelletized bedding is preferred between 1 cm and 5 cm in particular. Here, too, it has been shown that this enables a particularly effective use.

[0020] The mixing ratio of bedding material and sodium bisulphate must be adjusted in order to achieve the desired mixing ratio. This can be done by adjusting the feeding rates in a screw conveyor. It is also possible to adjust and homogenize the desired mixture and then feed this mixture to the matrice, taking into account the length of the feed section.

[0021] In principle, the bedding material is crushed before the pressing process in such a way that the material can be processed into pellets using the method according to the invention. For example, the bedding material, in particular the straw, has a d 50 value of 1500 pm to 4000 pm.

[0022] After the homogeneous mixture has been introduced into the matrice of the press, a pressure is applied. This should not exceed 150 bar. The pellets cannot be kept stable at a higher pressure. The pressure must not fall below 100 bar, as otherwise the material to be pressed cannot be pressed through the matrice and the matrice will clog and the system will come to a standstill.

[0023] After the pellets have been produced, they can, if desired, be further processed into granules or finer bedding material using suitable techniques, e.g. a granulating mill. This serves to adapt the litter texture so that the floor area can be better covered with the same amount of litter when used in stables if that is desired.

[0024] The bedding material contains a certain amount of water before the pressing process. This is an inherent characteristic of the material itself. It is also possible that water is added to the bedding material to enable better processing. After pressing in the matrice, however, the water content of the pelletized bedding is preferably 15 percent by weight or less, in particular preferably 10 percent by weight or less, especially preferably 5 percent by weight or more. Here too, the percentage by weight is based on the total weight of the pelletized bedding. The water content ensures that stable pellets are obtained.

[0025] It is particularly preferable to dry the pelletized bedding after pressing. This can be done using air. The temperature of the air is particularly preferably between 70 °C to 80 °C. Drying takes place over a period of 20 to 30 minutes or longer, for example. This gives the pelletized bedding a particular strength so that it can be packaged for storage and transported without any problems. At the end of the manufacturing process, the pelletized bedding is packaged so that it can then be sold. However, the packaging is particularly designed in in such a way that no moisture from the air reaches the pelletized bedding. In this way, a pelletized bedding can be obtained that is stable in storage, retains its shape and has only a small amount of fine material even after transport, so that the pelletized litter is of high quality even after transport and storage.

Claims

Claims1. Process for the production of sodium bisulphate-enriched pelletized bedding, characterized in that comminuted litter material is mixed with sodium bisulphate and this mixture is pressed in a matrice at a pressing ratio of 1 : 1.5 to 1 :5.

2. method according to claim 1, characterized in that it comprises the following steps: a) Provision of the bedding material, b) Shredding the bedding material, c) Preparation of the sodium bisulphate, d) homogeneous mixing of the crushed bedding material and the sodium bisulphate, and e) introducing the resulting mixture into a press with a matrice with a pressing ratio of 1 : 1.5 to 1 :5.

3. process according to claim 1 or 2, characterized in that the matrice has a compression ratio of 1 :2 to 1 :4, preferably of 1 :2.5 to 1 :3.

4. method according to at least one of claims 1 to 3, characterized in that the bedding material is selected from straw, chopped straw, softwood shavings, lignocellulose, maize silage, rye straw, wheat straw, triticale, spelt, spelt husks, sunflower husks, hay and / or grass, or in particular consists of one of the aforementioned materials.

5. process according to at least one of claims 1 to 4, characterized in that the proportion of sodium bisulphate in the pelletized bedding is at least 5% by weight, based on the total weight of the pelletized litter.

6. process according to claim 5, characterized in that the proportion of sodium bisulphate is from 5 to 55% by weight, particularly from 6 to 45% by weight, preferably from 7 to 30% by weight, preferred from 8 to 25% by weight and particularly preferred from 10 to 20% by weight, based on the total weight of the pelletized litter.

7. process according to at least one of claims 1 to 6, characterized in that the diameter of the pelletized litter produced is between 3 and 10 mm, preferably from 4 mm to 7 mm.

8. process according to at least one of claims 1 to 7, characterized in that the length of the pelletized litter produced is from 1 cm to 5 cm.

9. process according to at least one of claims 1 to 8, characterized in that the mixing ratio of bedding material and sodium bisulphate is adjusted by conveying quantities in a screw conveyor.

10. process according to at least one of claims 1 to 9, characterized in that the mixing in step d) does not take place directly above the press.

11. process according to at least one of claims 1 to 10, characterized in that pressing is carried out at a pressure of up to 150 bar.

12. method according to at least one of claims 1 to 11, characterized in that the pelletized bedding has a water content of 15% by weight or less, in particular 10% by weight or less, preferably 5% by weight or more, based on the total weight of the pelletized bedding.

13. process according to at least one of claims 1 to 11, characterized in that the pelletized bedding is finally dried.

14. Pelletized bedding obtained by a method according to at least one of claims 1 to 13.

15. Granules obtained by post-processing a bedding according to claim 14, in particular by post-processing with a granulating chair.