- Green Technology
How to Make Fuel Briquettes – Sawdust Briquettes –and Wood Pellets
Lignin - Lignen
The secondary cell walls of wood and biomass are put together by a complex chemical called lignin (lignen). If you saw wood into powder and then melt the lignin in the powder, the lignin will again bind the powder together into solid wood. This is the idea used in binding sawdust into sawdust briquettes. To melt the lignin from sawdust requires a lot of pressure which can not be achieved by the simple briquettes press used in simple briquette making.
Starch Is Expensive
Sawdust can also be mixed with a starch paste and be bonded together as a briquette by pressing using simple briquette making presses. Such a briquette is very light, and it burns very fast, and produces a lot of smoke. To make it stable and last longer, just mix sawdust and charcoal fines at the ratio of 20/75 and add 5 - 6% starch binder. Starch is relatively very expensive and can be replaced by mashed newsprint/waste paper pulp as a binder. To read more on possible recipes of making charcoal briquettes using starch as a binder go to the article How to Make Briquettes – Charcoal Briquettes - Charcoal Briquette Ingredients and Composition.
Sawdust is Easily Available
Sawdust is the by-product you get after cutting lumber with a saw. Sawdust is composed of fine particles of wood which takes a long time to discompose. High concentration of sawdust in one area is considered an environmental problem. Sawdust is easily available at almost free of charge from saw mills as well as from individual carpenters within many societies. Sawdust contains a lot of energy and is therefore ideal for making inexpensive fuel briquettes. The good thing about sawdust is that we can utilize its lignin to bind the briquettes instead of using starch binder which is the most expensive component in charcoal briquettes.
To get sawdust to bind together using its own lignin, you need to press the sawdust at such high pressure of 60 tonnes per cm². This is a very high pressure that the briquette comes out the orifice charred and steaming hot. It is this compression pressure that heats up the sawdust to a temperature of about 120°C. This temperature in turn melts up the lignin in the sawdust and upon reduction of pressure and cooling the sawdust is bonded together as a solid briquette. It is very important that the sawdust should be completely dry and at moisture content of about 8% and 12%. In addition, the sawdust should be of consistent size with fines and shavings. These sawdust briquettes are smoky and need to be carbonized to fit in the high end market. One good thing about fuel briquettes pressed that much is that they are compact and dense than wood and occupy less space for economical transportation and storage.
Wood Pellet Making Machines/Sawdust Briquette Making Machine
In order to achieve the pressure required to press the sawdust to release lignin, you will need to purchase a wood pellet making machines or sawdust briquette making machine. Ideally, they actually are the same machines and by changing the dies and rollers you can get pellets, briquettes or those other tubular shapes.
In china you can purchase a good wood pellet making machines or sawdust briquette making machine for about $6000 ex-works. You will then have to add the cost of transportation, handling and clearing and with roughly a total of $10,000 you should have the machine in your manufacturing yard. A good machine should be able to produce about 1000 kg of pellets/briquettes per hour.
Maintenance of Briquette Making Machine
The moving parts, rollers and dies will need to be replaced from time to time and this can turn out to be a big cost. And in addition you will need to pay for electricity that you will use in running the machine. The electricity can be about 7% the energy of the fuel briquettes made.
Calorific Values of Typical Fuels
Type of Fuel
Charcoal Fines Briquettes (No Adulteration)
If you would like to learn How to Make a Simple Briquette Press, you can check it here.