What Is the Working Principle of the Biomass Molding Machine?
The Core Principle: Pressure and Heat Activate Lignin
Biomass is composed of cellulose, hemicellulose and lignin. Lignin is the natural binder that holds plant fibers together. When the raw material is compressed in a biomass molding machine, the pressure and the friction heat generated inside the pressing chamber soften the lignin, turning it into a sticky, glue-like material. As the material passes through the die, this softened lignin coats the fibers and bonds them into a solid, dense briquette. When the briquette cools, the lignin hardens again and keeps the shape permanently. This is why a well-designed biomass molding machine can produce firm briquettes without adding glue, starch or any chemical binder.
How the Molding Process Works Step by Step
The process starts with feeding. Raw materials such as straw, rice husk, sawdust, peanut shells and wood shavings are fed into the machine after being crushed to a suitable size, generally below 50 millimeters in length. The material then moves into the pressing chamber, where a screw or piston applies continuous high pressure. Friction between the material, the screw and the die wall raises the temperature of the material to the range where lignin softens. The compressed material is extruded through the die in a continuous column, then cut into briquettes of the desired length. The finished briquettes are discharged, cooled and packed.
Typical Technical Specifications
The table below shows typical specifications of common screw-type biomass molding machines for reference. Actual models differ by manufacturer, but the power, die configuration and product size follow similar patterns.
| Model | Installed Power kW | Number of Die Holes | Briquette Size mm |
|---|---|---|---|
| Model A | 45 | 36 | 32 x 32 x 50-100 |
| Model B | 75 | 48 | 32 x 32 x 50-100 |
| Model C | 110 | 72 | 32 x 32 x 50-100 |
| Model D | 132 | 90 | 32 x 32 x 50-100 |
| Model E | 200 | 120 | 32 x 32 x 50-100 |
| Model F | 250 | 150 | 32 x 32 x 50-100 |
In general, a higher installed power corresponds to a larger number of die holes and a higher output. The briquette size is determined by the die configuration and can be adjusted according to the requirements of the heating equipment that will burn the fuel.
Raw Material Requirements for Stable Molding
Molding quality depends strongly on the raw material. The particle size should be small enough to pack tightly, usually below 50 millimeters for screw-type machines, and the moisture content should be controlled in a suitable range, typically between 8 and 12 percent for most biomass. Material that is too dry produces loose briquettes that crumble, while material that is too wet slips inside the chamber, reduces friction heat and makes the briquette soft. For best results, mix different fiber materials in a stable ratio and keep the feed rate constant during production.
Frequently Asked Questions
Does the biomass molding machine need additives to bind the material?
No. The machine uses the natural lignin in the biomass as the binder. High pressure and friction heat soften the lignin, so no glue or chemical additive is required.
What is the ideal moisture content for briquetting?
Most biomass materials mold best at a moisture content between 8 and 12 percent. Adjust the level according to the specific material and the machine type.
What size should the raw material be before molding?
The raw material should generally be crushed to below 50 millimeters in length so that the fibers can pack tightly in the pressing chamber.
Why do my briquettes come out loose and break easily?
Loose briquettes usually indicate low material moisture, insufficient pressure, worn die parts, or a feed rate that is too high. Check these four factors in order.
What is the difference between screw-type and piston-type molding machines?
Screw-type machines extrude a continuous column through the die and typically produce briquettes with a central hole, while piston-type machines produce solid briquettes in a stamping motion. Both rely on the same lignin-binding principle.
