Most people these days have at least a small concern about the long-term effects they are having on the environment – this has lead them to increasingly turn to clean burning and more efficient fuels such as biomass stoves which burn wood pellets at a very high temperature, heating rooms and houses from the heated steam. The pellets themselves cost significantly less than traditional fuel sources, and burn cleaner than any fossil fuels are capable of.
Wood pellets are actually pretty small, and shaped like a small pill – they also usually have a shine to the outside. Of course they aren’t singe piece of wood but are made of lots of small pieces of wood waste which have been tightly compressed and heated to make these perfect little pellets.
Frequently wood pellets are produced from recycling material, usually from the sawdust waste at timber mills. The waste is collected and taken to pellet production facilities who are best equipped to make good quality wood pellets and then send them out through the country.
Before the collected sawdust is compressed into a very small pellet, it is first put through a machine known as a “hammer mill” which smashes the sawdust down into a dough-like mixture and then feeds it into a pres. The waste is then pushed through a die filled with specifically sized holes, around 6mm in diameter! The huge amount of pressure forces the wood to compress and it is simultaneously heated to cause a bond. The lignins which are naturally present in most softwoods work like a glue to bind the pellets in shape.
Regulations dictate that wood pellets for biomass burning need to have less than 10$ water content – this is to increase the burn efficiency. They must also be uniform in density for ease of burning, and should be dense enough to sink in water. Finally they need be solidly made with very little dust or ash the best way to do this is with heat and pressure.
When wood is processed through a hammer mill it looks remarkably different from when it is used for furniture or pallets. The mill breaks down the very fibres in the wood to make a seamless mess; this also means that different types of wood can be used together as they all end up in fibres anyway.
One of the most important regulations about the wood used to make wood pellets is that it cannot be made from recycled wood. This is because it could have been exposed to any number of chemicals or contaminants, which would stop them from burning clean and could damage the environment, the burner and even the whole home. This means that items like painted wood, coated panels or recycled particle board simply aren’t suitable for making wood pellets.
A combination of the low emissions which come from wood pellets, and the regulations which require trees to be planted for every one used for pellets, this is one of the cleanest types of energy available at the moment. With advancements pushing wood pellets to be more clean and more efficient, and fuel prices rising, they are becoming an increasingly popular choice of alternative heating!by