This is Steve Ember with the VOA Special English Agriculture Report.
In many parts of the world, people burn wood and other agricultural products for cooking and heating. However, as populations increase, materials for burning can be more difficult to find. One way to make better use of such materials is to press them together into a solid fuel. This is called briquetting. The objects that are burned are called briquettes. Briquettes are usually no bigger than a person's hand. They can be any shape.
Charcoal is a common form of briquetting material. It is found throughout the world. Charcoal burns with a higher heat energy value per kilogram than wood.
Charcoal briquettes are made from specially treated wood. Briquettes can also be made from many other kinds of materials. These include rice coverings, paper, food wastes, fish wastes, and wastes from processing coconuts and coffee.
In general, anything that burns but is not found in an easy-to-use size can be used to makes briquettes.
The first step in briquetting is to collect a large amount of the material. Then the material is cut or crushed to make it smaller. Next it is combined with a small amount of water and a substance called a binder. A binder keeps the material from falling apart when the pressure is taken away. Clay, mud, cement and starch are commonly used binders.
At this point the material and binder may be partly dried. Finally, the substance is pushed together under high pressure in a machine. The machines used for families or in small briquetting businesses are often operated by hand. They shape the material into briquettes that can be burned immediately or stored and sold later.
The same machines that make blocks and bricks from mud and straw can be used for briquetting. An example of such a machine is a Cinva Ram.
Machines with electric motors can also be used. A twenty horsepower motor can be used for briquetting with rice husks. Two workers using such a machine can produce one-hundred-fifty kilograms of briquettes every hour. The machine can operate twenty-four hours a day.
You can get more information about briquetting from the group Volunteers in Technical Assistance. VITA is on the Internet at v-i-t-a dot o-r-g.
This VOA Special English Agriculture Report was written by Gary Garriott. This is Steve Ember.