Briqueting process converts low bulk density biomass materials into high density fuel briquettes
In the briquetting plant, ground chacoal burned from sawdust and other wood by-products are compressed into briquettes along with a binder and other additives that helps the briquette to burn. The selection of binder and additives is related to the quality and cost of the briquettes.
The selection of binder and additives is related to the quality and cost of the briquettes. Charcoal is totally lack of plasticity, thus it needs addition of a binding material to hold the briquette together for transportation, briquette forming and storage. Every particle of char is coated with binder, which enhances charcoal adhesion and produces identical briquettes. After the wet pressed briquettes are dried the binding operation is completed.
Starch as a binder in Briquettes
The common starches we usually use as binders are from maize (corn starch), potato, and tapioca and less-common starches from rice and wheat. Normally, a starch needs to be gelatinized by thorough cooking in water at a temperature between 60°C to 80°C. This temperature disrupts the inter-molecular bonds, creating hydrogen-bonding sites for attaching additional water molecules and makes the starch soluble in cold water. After cooking, the starch is dried in a spray dryer, drum dryer, or extruder. You can buy pregelatinized starch, but it’s substantially more expensive than raw starch.
Modified Starch is the most common binder though it is usually expensive. However, it doesn’t have to be an food grade. In general, about 4.0-8.0% of starch is needed to make the briquettes.