WOOD_PELLET_MILLWood pellet fuel has emerged as a prominent alternative to traditional fuels worldwide. The utilization of wood pellet mills has significantly increased due to the rising popularity of pellet fuel. Specifically designed for compressing wood materials into pellets for heating fuel, the flat die pellet mill comprises several components: clutch assembly, gear box, main spindle box, rollers, upper body, feeder, flat die, engine, and base. The process involves feeding the feedstock into the feeder, where rollers compress materials, extruding them through die holes to produce wood pellets. Critical components like flat dies and rollers are crafted from alloy steel, known for its robust and malleable texture. The pellet mill operates through a heavy-duty gearbox, ensuring continuous production.
Renowned for its simplicity, high automation, and minimal labor requirements, wood pellet mills are suitable for home use or small enterprises engaged in biomass pellet fuel production. These mills can be configured to run on either diesel or electricity, catering to various needs. Their application extends beyond wood chips, wood shavings, and sawdust to encompass cotton or beanstalks, peanut shells, sunflower husks, and more.
The portable wood pellet mill stands out due to its exceptional performance:
– **Continuous Operation:** Capable of running steadily for over 24 hours.
– **Safety and Efficiency:** High security, low noise, and minimal energy consumption.
– **Ease of Maintenance:** Standardized rollers and dies facilitate easy replacement.
– **Customizability:** Adjustable pellet size and length by changing dies with different specifications.
– **Enhanced Monitoring:** Provides good visibility, allowing direct monitoring of the pelleting process, aiding in immediate troubleshooting during production.
The wood pellet production process involves several key steps:
1. Raw material collection or waste gathering.
2. Size reduction using a hammer mill (to 3-5mm).
3. Drying the raw materials to reduce bamboo moisture to around 12%.
4. Pelletizing using a wood pellet making machine.
5. Pellet cooling and packing.
It’s crucial to note specific guidelines during the production process:
1. Reduce material size to 3-5mm during crushing.
2. Bamboo moisture should be reduced to around 12% during drying.
3. No binders are necessary for pelletizing, as lignin in wood acts as a natural binder aiding in the process.
Wood materials contain cellulose, hemi-cellulose, lignin, and a small amount of mineral ash, with varying percentages based on the type:
|
Wood components
|
Softwood %
|
Hardwood%
|
|
Cellulose
|
45-60
|
40-55
|
|
Hemi-cellulose
|
35-40
|
20-40
|
|
Lignin
|
25-30
|
15-30
|
|
Ash
|
0.1-1.0
|
0.5-1.5
|
Wood waste, predominantly from sawmilling, plywood, particleboard production, includes sawdust, wood shavings, bark, and trimmings. Different wood waste types possess distinct calorific values and physical properties:
A. Calorific values of various wood waste types
|
Dry type
|
Calorific Value (kj/kg)
|
|
Wood waste derived from treated wood
|
17525
|
|
Chipped demolition wood derived from treated wood
|
17792
|
|
Park waste wood derived from untreated wood
|
18278
|
|
Wood industrial wood waste, dust
|
18391
|
B. Physical properties of various wood waste types
|
Type
|
Moisture (%)
|
Density (kg/m3)
|
Ash (%)
|
|
Sawdust
|
50.33
|
1.56
|
1.12
|
|
Large wood, bark
|
46.89
|
2.88
|
37.93
|
|
Mixed wood, bark
|
46.72
|
1.81
|
9.32
|
Features of Wood Pellets
Wood pellets boast higher calorific values (3900-4800 kilocalorie/kg), with 75-85% carbon content, 3-6% ash content, and 1-3% moisture content. They offer various advantages:
– Consistent high quality in shape and moisture.
– Environmentally compliant burning capabilities.
– Ideal for automatic combustion operations.
– Utilization of regional renewable resources.
– Higher energy density than wood chips, facilitating transport and storage.
– Suitable for energy systems ranging from small to large scales.
These wood pellets find wide applications, primarily as fuel for home pellet stoves and medium/small-scale electric power plants, offering affordability, sustainability, and convenience in heating. Additionally, they serve as bedding for animals, providing a sterile, low-dust environment. The biodegradable nature of wood pellets makes disposal easy, allowing their use as fertilizer or in compost heaps.
