Straw pellet
Straw pellets (from English : pellet = globules, pill ) are pellets , i.e. small cylindrical or round bodies, made from pressed cereal straw or oil plant straw . Like wood pellets , they serve primarily as a renewable energy source ( bioenergy ), but are also increasingly being used as litter for stable animals and pets.
Manufacturing
To produce the 6-10 mm thick and a few centimeters long pellets , straw is very finely chopped or ground, moistened with the help of steam, and the resulting mass is pressed through flat matrices . The diameter of the straw pellets corresponds to the diameter of the holes in the flat die . So that straw pellets do not ferment or go moldy, the residual moisture in the pellets must not be> 15%. Individual systems therefore provide for a downstream drying process.
The straw pellets are usually transported and stored in big bags , in individual small plastic or paper sacks or as bulk goods .
use
Energetic use
One ton of straw pellets has a calorific value of around 5000 kWh. With special heating systems in which the pellets are computer-controlled via a screw conveyor into the combustion chamber, they can be used almost as conveniently as oil or gas for heating buildings. The price of the pellets in 2005 corresponded to a heating oil price of approx. 0.24 to 0.28 euros per liter. The typical retail price of bagged goods for purchases in the tonne range was around 190.00 euros per tonne, gross (plus transport costs).
Straw often has a higher content of potassium , chloride and sulfur than wood. Therefore, these chemical elements or their combustion products are also found in the flue gases. The combustion products formed cause a strong chemical attack on the flue gas pipes . There is also more slag (approx. Four to six percent by weight ) compared to approx. One percent by weight with wood pellets. This has a very strong tendency to clump together, so that the combustion process is severely disrupted: It is therefore not possible to permanently burn straw pellets in normal wood pellet stoves without problems.
Material use
Straw pellets have a high suction power of over 400% of their own weight. This value is around 12 times higher than that of long straw. The reason for the reduced suction power of long straw is the outer layer of lignin that surrounds the plant and protects it from external weather conditions. During the mechanical digestion by z. B. Hammer mills , the lignin layer is broken and the entire suction potential is released.
Due to the high suction power, straw pellets are used more and more often as bedding in horse stalls, broiler farms, cattle farms and with small animals.
consumption
The consumption of a 10 m² horse box is around one ton of straw pellets per year. Consumption can vary depending on the animal and its manure behavior. The consumption is calculated using the basic litter amount (approx. 13 kg per m²), which occurs twice a year, and the weekly re-litter amount of approx. 15 kg per 10 m² box.
application
After cleaning the box, 15 kg of straw pellets per m² are evenly distributed as basic litter in the box. This area is then sprinkled with water using a watering can or hose until the top layer of the pellets disintegrates. As part of the daily cleaning process, the boxes are peeled off and damp spots are removed. The removed amount of straw pellets is then sprinkled. After a few days, a dry, soft and joint-friendly mattress forms.
swell
- ↑ Comparison of the composition of different fuels ( Memento of the original from April 14, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF file; 716 kB).
