Application

Raw materials for making pellets

GEMCO pellet machine can process various biomass materials, including agriculture and forestry wastes, wood processing waste, household garbage, etc. The followings are the most common wood pellets materials.

• Sawdust: It is an ideal raw material for making pellets. It has suitable size and good adhesive force. Sawdust pellets has high hardness and smooth surface. It has the least abrasion to the pellet mills. Sawdust also includes wood powders, wood shavings, wood chips.
• Grass: It is usually made into animal feed pellets, sometimes biomass pellets. Grass pellets have the same BTU as sawdust pellets, but the ash residue is higher. Fresh grass has high water content, it usually need drying.
• Alfalfa: It grows quickly and adapts to various environment. It can be reaped for 4 times a year, and 12 times in some areas. With high nutrient content, alfalfa is an excellent feed for animals (such as  chickens in layer cages.). Making alfalfa pellets make it more palatable and easier to digest for animals.
• Rice husk: With the large production of paddy every year, rice husks also has large amount, but 70% of them haven’t been utilized. The calorific value of rice husks is 1/2 that of coal and 1/3 of diesel, but its cost is rather low.
• Crop straw: includes wheat straw, rice straw, maize straw, cotton straw, etc. They make up 50% of the crop yield. Making straw pellets is more environment friendly than leaving them on farm or burning directly. Crop straw has high cellulose and lignin content, high calorific value, and low water content.
• Waste papers: they are very common at home, office, classroom, store, and streets. Papers are made of wood and sawdust. Waste papers take up large space. They are easy to catch fire or get damp. Making paper pellets can increase their density and unify their size, solve pollution and save fuel cost.
• EFB(empty fruit bunch): It is a by-product of oil palm. EFB is abundant in Southeast Asia countries. EFB has large volume, with rich cellulose and lignin, which is an excellent material for making pellets. But it need drying and crushing to before making pellets.
• Leaves: They are easy to obtain in autumn and winter in house and yard. Leaves have high fiber content and high calorific value. They are easy to clean and pelletize. Leaves pellets are low-cost with little smoke or ash emission.

Requirements on the raw materials

Moisture content: 14%-20%. Dry materials are hard to mold, while damp materials make the wood pellets too loose. To keep the raw materials with suitable moisture, you may need a dryer machine.

Raw material size: under 5mm. The size of raw materials should be smaller than the hole size of the pellet mill die. As the hole size are usually 6mm, 8mm and 10mm, the raw materials should be under 5mm. You may need a hammer mill or a wood crusher to process the materials.

Are binders necessary? Generally, you don’t need to add binders for making pellets. The lignin in biomass materials will melt in pelletizing and play the role of binders. But some raw materials like rice husks contains little lignin, so you can add some binders or mix them with other materials to improve the adhesive force.

Pellet machines for various biomass materials