Wood Pellet Mill
What is Wood Pellet?
Wood pellet is a kind of solid fuel, which is produced by crushing and compressing the sawdust and ground wood chips, finally forming the wood pellets with the same size. Generally, the pellet is 1-2cm in length and 6, 8, 10, or 12mm in diameter. There is no additive added during the wood pellet making process.
Characteristics of Wood Pellet Fuel
| Amount of heating generation (lower limit) | 4.7 kWh/kg = about 4,000 kcal/kg |
| Kerosene conversion value | Pellet: kerosene = about 2.1 tons:1m3 |
| Volume weight | 650 kg/m3 |
| Hydrous rate | ＜15% |
| Ash content | wood except bark: under 0.5%, bark: over 2.5% |
Elemental Analyses and Heating Values of Fuels
| Elements | Wood pellets | Bark pellets | Wood briquettes | Wood logs (%) | Oil (%) |
| Ash (%) | 0.5 | 3.7 | 0.3 | 0.3 | 0.6 |
| Moisture (%) | 7.6 | 7.8 | 7.5 | 15/26/38 | 0 |
| LHV(MJ/kg) | 19.0 | 20.1 | 18.9 | 19.0 | 43.1 |
| Carbon (%) | 50.2 | 52.1 | 50.6 | 50.6 | 87.5 |
| Oxygen (%) | 43.2 | 37.8 | 42.7 | 42.7 | 0 |
| Hydrogen (%) | 5.9 | 5.9 | 6.4 | 6.4 | 12.7 |
| Nitrogen (%) | 0.08 | 0.48 | 0.05 | 0.05 | 0.1 |
| Sulphur (%) | ＜0.01 | 0.03 | ＜0.01 | ＜0.01 | 0.09 |
Compared with other biomass fuels, wood pellet is very easy to manage, and it is a good choice for automatic combustion installation because it can remarkably save time and labor. What’s more important, wood pellets are easier to use, less storage space needed, and less dangerous to deliver than fossil fuels. They are more advantageous because of the high energy content by weight of almost 7,750 Btu per pound. Besides, wood pellet is heat-treated, so it can be stored for a long time with less risk of molding. All the mentioned properties make wood pellets be an ideal choice for families, farms, small biomass pellet plants, etc.
What You Should Know about Pelletizing
| Raw materials | wood chips, tree shavings, waste paper, house refuse, agro-waste, animal waste, etc. |
| Moisture content | Less than 15% |
| Size of feedstock | Should be no larger than the diameter of die holes |
| Final pellets diameter | 6mm or 8mm(or depend on customer’s requirement) |
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400 Multi-functional Pellet Mill Model: WHIR-400 |
How to Make Wood Pellets
1.Gather the wood to be used and reduce the size of wood materials. Chip or grind the feedstock until the size of wood materials is no larger than 3mm.
2.Dry the materials. Moisture content should be less than 15%. Leave the sawdust in the sun to dry naturally, or using a dryer machine until it is dried to the desired moisture level.
3.Feed the wood materials into a wood pellet mill. Our pellet press is a flat die pelletizer, and the wood pellets we made are consistent in density and moisture level.
4.Cool the pellets thoroughly. When the pellets come out of the pellet making machine, they are high in temperature and moisture content. You’d better spread them out and allow them to cool through air-dry.
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Simple Ways to Check Wood Pellet Quality
Follow the following simple methods, you can quickly check out the quality of the wood pellets you have made.
♤ Put a handful of wood pellets into a plastic bag and smell the odour from the pellets. They should smell of freshly-cut softwood, if not, beware.
♤ Take one long pellet and light it at the tip. The smoke should smell of burning wood. If not, it is not good in quality.
♤ Place a small quantity of pellets in a glass of water. The pellets should dissolve into sawdust within a few minutes. If not, an additive or improper raw materials might have been added. Once the pellets have been dissolved, swirl the glass and observe what precipitate is in the bottom of the glass. The heaviest particles will settle there. If there is a large amount, it might be possible that pellets contain impurities, which will increase the amount of ash and the risk of sintering.
