Is It Possible To Build A Homemade Pellet Mill?
Making a homemade pellet mill is technically possible, however it is neither cost effective or a practical option. To be able to consistently and efficiently process wood into fuel pellets requires some fairly heavy engineering to cope with the forces involved. Please watch the video below of our Mini Pellet Mill as an example.
On the PelHeat website we promote a small pellet mill which can be used in the home. Small pellet mills are generally all flat die pellet mills. The flat die pellet mill is a vertical design. The rollers sit on top of the die, applying pressure vertically to the top surface of the die. Depending on the design, either the roller shell or die will be stationary and the other will rotate. Material enters from the top, and falls between the rollers and die. The pellets come through the bottom of the die, and are cut to length via a knife. Pellet length is much more important than many people appreciate. Some pellet stove augers cannot handle oversized pellets, causing damage to the auger or simply blocking and causing the stove to stop operating properly, therefore shorter pellets are better and very long wood pellets.
Before the raw material is suitable for the pellet mill it first must be prepared correctly. For example if you wish to produce 6mm pellets, which is the size of pellet most pellet stoves use, you must provide the pellet mill with a raw material of 6mm or below. Therefore this means sawdust is appropriate, however wood chips are going to require more processing. After the wood has been chipped the best piece of equipment to reduce the chips further in size is a hammer mill. A hammer mill works on the principle of attrition. Through the speed impact of the hammers on the wood chips the chips are shattered into smaller particles. To make sure the particles are below 6mm a screen is placed in the hammer mill. Therefore no particles can escape the hammers until they are below 6mm in size. Once the material is of a suitable size, generally it must be dried before entering the pellet mill. This is particularly true if the wood chips are from fresh virgin wood. For small scale pellet production the most practical and affordable way of drying the material is through a flash dryer. Flash dryers are also known as pipe dryers or air current dryers. The hot air is generated in the stove burning wood logs, chips or pellets. From the stove there is then a series of pipes with expansion chambers. Therefore as most biomass materials need to be dried before they can be made into pellets, this generally means making pellets at home is not practical. However the PelHeat Mini Pellet Mill is available as a single phase machine for home use if needed. The Mini Pellet Mill is generally used for research and testing purposes not just persona use.