There are many kinds of raw materials for wood pellets. They include: wood, rice husk, grain husk, straw, sawdust and so on. These raw materials are pressed into wood pellets. The fuel made through growable organic matter is also called: biomass fuel.
Raw Material Pre-processing Stage
Raw material screening: use linear vibrating screen or tumbler screening equipment to screen out metal objects, stones and other debris in wood chips and sawdust. Ensure the purity of the raw material meets the subsequent pelletizing requirements.
Crushing: The raw material is crushed by hammer crusher to control the particle size of the raw material in the range of 3-5mm to enhance the efficiency of subsequent compression molding.
Moisture control: In order to meet the needs of granulation, the moisture content of raw materials should be controlled within 15%. Natural drying or low temperature dryer can be used for pretreatment.
Pellet Molding Stage
Compression molding: flat die pellet mill or
vertical ring die pellet mill is used. The pressure is 60-100MPa and the temperature is between 80-100℃. Make the lignin soften and bonded into dense and compact pellets.
Mold parameters: the length/diameter ratio (L/D) of the mold cavity is controlled between 4-6. Molding rate can reach more than 95%.
Cooling and shaping: through the counter-current coolingtower to make the temperature of the particles will be room temperature, the hardness can reach more than 50N anti-breaking standard. Cooling to prevent pellet deformation or biodegradation.
Packaging And Storage
Packaging standard: choose moisture-proof PE film plastic bag, woven bag, ton bag packaging and so on.
Storage standard: In the process of storage and transportation, it is necessary to avoid sunshine, rain, heavy pressure and so on. The relative humidity of the storage environment should be lower than 60% to avoid moisture absorption and expansion of the granules. The quality of the quality pellets and the use of the effect.
In short, to produce high-quality wood pellets need to choose the right raw materials and equipment. At the same time, it is also necessary to accurately control the pellet process and technology to facilitate the good results.