Besides being cost-effective, another positive attribute of wood pellets is that they are carbon neutral. The trees from which the pellets are made, absorb the same amount of carbon dioxide as the pellets emit upon burning. With all these positive factors in mind, let us now roll up our sleeves and get down to the procedure of making this excellent form of alternative fuels.
The two most important requirements for making wood pellets are the raw materials and the equipment.
Potential materials are not a matter of concern. Any type of wood, both soft and hard, can give excellent results. The only thing we should keep in mind while selecting the raw material, is that, it needs to be reducible to its granular form.
Here we are going to construct wood pellets at a household level, hence we do not need all the heavy machinery like hammer mills, dryers, pelletizers, coolers, baggers, and boilers. A simple small scale mill is sufficient to reach to our end product. However, if the size of the particles that are being used as raw material are large, then we may need a small hammer mill to crush the material.
With all the requirements at hand we can now jump straight into the process of how to make wood pellets.
The dried saw dust, wood shavings, and pieces, need to be gathered first. Any particle that is more than ¼ inch in length must be reduced to grains. This can be done by hammering the particles manually, but for better results it is always preferable to use a hammer mill. The final raw material that will be going through the remainder of the process, should be uniform and in a granular form.
The next step is to remove any moisture that may be present in the raw material. The reduced particles are then dried in a dryer at the temperature of 600 degree Fahrenheit. The heating process should be carried out at a very high pressure. Wood contains lignin, a natural substance that acts as glue. Since we are using saw dust, obtained from wood, as our raw material, we do not need to add any binding agent to hold the pellets together. However, if the amount of lignin present in the wood is not sufficient to bind the material, then some external adhesive like vegetable oil, clay, starch, cooking oil, or wax can be mixed along with the saw dust, during the heating process.
The moisture free substance that we obtain from the drier is then put into the pelletizer. The pelletizer consists of a die and an array of rollers. The rollers force the substance to pass through the die, which gives the pellets a tubular shape. It should be ensured that this process should also be carried out at a high pressure, to allow the adhesive to just bind the material and not soften it.
The pellets that we obtain from the pelletizer, are then cooled down. This is done by putting them in a pelletizer at a temperature of around 5 degree Fahrenheit. Only the hardened and complete ones should be put into the cooler. There should not be any loose dust particles or broken ones.
The completely hardened pellets that we obtain from the cooler are then stored in the containers at a very high pressure. The wood pellets that we obtain from the cooler contain about 5 to 15% moisture. For better results, the pressure, temperature, and time duration of cooling should be maintained such that the pellets contain only 15% moisture.
The simple process described above allows us to get a clean, renewable, and cost-effective form of energy. Wood pellets can be manufactured not only from the wood wastes, but from straw, cardboard, grass, and other plant material. A simple pelletizer, in your possession can save you a load of money from buying fuels.