Elephant Grass Pellet Mill

Elephant Grass commonly known as Miscanthus, is a high yielding energy crop that grows over 3 metres tall, resembles bamboo and produces a crop every year without the need for replanting. The rapid growth, low mineral content, and high biomass yield of Miscanthus increasingly make it a favourite choice as a biofuel, outperforming maize (corn) and other alternatives.

Miscanthus/Elephant Grass Properties

It is caused by squeezing raw materials such as rice husk and straw under pressure at normal temperature by using rollers and ring die granulators. Convenient transportation and storage, meanwhile, its fuel performance is greatly improved. The particle size of raw materials can be divided into coarse particles, medium particles and fine particles. Above 3.0 is coarse grain. Medium and fine granules have better granulation properties, low energy consumption and less wear on the die roll. When medium and fine granules are quenched and tempered, they have more surface area than coarse grains in contact with steam, and steam easily penetrates the particles. The core makes it fully mature, produces physical and chemical changes, and improves granulation quality. Coarse particles cannot be completely penetrated by steam; in addition, when coarse material is granulated, the surface area of ​​contact with each other is less than that of medium and fine particles, and the adhesion is poor. After granulation, the particle swelling rate is large and cracks easily; High density, good ability to pass through die holes, less wear on die holes, and high productivity.

Firstly, Miscanthus can be used as animal bedding – production of horse bedding

Then, Miscanthus is considered to be a raw material for the paper industry, a source of fiber to be used in building materials.

And, Miscanthus is also widely used as a fiber material in geo-textiles. Its use as canes to support ornamental pot plants and the use of miscanthus ash arising from combustion processes as a fertilizer is also being done.

The most important one is miscanthus has 80-90% of the energy value of the initial biomass material and can be manufactured into pellets or briquettes used as a raw material for energy production and co-firing. Energy production alternatives that have been examined are co-combustion with coal and combustion in heating plants.

1. Chopping

When elephant grass is harvested and baled in the field to increase density and maximize transport efficiency, it is then transported to the processing facility where it is chopped. elephant grass is chopped into fibers (25mm-35mm lengths) using a chopper or bale shredder then dried and pelleted.

2. Drying

The chopped miscanthus is further dried using a drier to allow processing to pellets. The required moisture content for pelleting is 10%-15%.

3. Grinding Processing

Before pelleting, the raw material must be reduced to an average particle size. For elephant grass, this will require two separate grinding operations. Bales will go through a chopper or bale shredder, then through a hammer mill.

4. Pelleting

Pellet formation takes place in the pellet mill where the feedstock is extruded through a ring die or flat die. As the pellets begin to extend outside the die, they are broken off with knives at a specified length. There are specialized pellet mill or pellet plant for elephant grass pellet production.

5. Cooling

Cooling is necessary t stabilize, dry and firm the pellets. The counter-flow cooler is the most popular type in the industry. It pulls ambient air through a bed of pellets to remove moisture and heat through evaporative and convective cooling.

6. Screening

When the pelleting is complete, some amount of the material will have not formed pellets. These materials are called fines. Screening is necessary to separate this materials out. It is then sent back through the pellet mill. When the pelleting process is functioning correctly less than 3% of the material will be screen out.

7. Bagging

After screening, pellets are bagged for residential sales or stored in bulk. For automatic packaging, pellet packing machine can service you. Pellets are conveyed to a bag-out bin where a scale measures the correct weight for each bag. The bags are then sealed and stacked on pallets.

1. Lower moisture content , which will be much more suitable for burning.

2. Lower ash content, which will reduce the risk of slag during burning.

3. Higher colorific value, which will generating more heat during burning.

4. Higher density which will be much more easy and convenient for transportation and storage.

5. Densified and uniform pellets makes the burning much more clear and stable.