Pellet

A pellet is a small, rounded or oblong particle produced by compressing material into a dense mass. Pellets are often uniform in size and shape, enabling consistent handling and combustion or processing. The term covers a broad range of materials, including biomass, plastics, metals, fertilizer compounds, and animal feed.

Pelletization is the process of forming pellets using heat, moisture, and pressure in a pellet mill or extruder. Materials are ground to powder, moistened, and pressed through dies to form cylindrical or spherical pellets. Post-processing may include drying, cooling, and coating to improve durability and handling. Common pellet sizes vary by application; for wood fuel, typical diameters are 6-8 mm and lengths around 10-30 mm.

Major uses: Wood pellets are used as a renewable fuel for heating and power generation, often in pellet stoves and boilers. Animal-feed pellets consolidate nutrients and improve intake and digestion for livestock and poultry. Plastic resin pellets are a raw material in the plastics industry, melted and molded into products. Fertilizer pellets provide nutrients in controlled-release formats. In sporting goods, pellets are used as ammunition in air rifles and pistols, typically made of lead or non-toxic alternatives.

Environmental and regulatory considerations: Pelletization can improve energy density and transport efficiency but requires energy input and may involve emissions during production. Wood pellets are graded by standards such as ENPlus or ISO 17225 to ensure quality, moisture, ash contents, and calorific value. Handling risks include dust explosion hazards and contamination in some materials.