C. F. Nielsen - Straw Briquetting 3-6 ton/h
Turn your straw from wheat, corn, miscanthus, hay, rape and other agricultural crops into valuable biomass briquettes to be used as industrial bio-fuel for power plants and heating plants etc. This is a large straw briquetting plant, comprising of a transport line for straw bales, shredder for straw, a hammer mill, buffer system, dosing system and 2 to 4 presses like BP 5500 HD (max 1400 kg/hour each) or BP 6000 HD. The actual capacity depends on the requirements for the briquettes and the quality of the raw material. A reduction of until 60 % may occur for production of consumer briquettes.
Densification is key issue
Dry straw left in the fields after harvesting is pressed into bales with a density of max 150 kg/m3, which is equal to a volume reduction of 3-5 times.
Straw briquettes have a bulk weight of 500–600 kg/m3, which is equal to a volume reduction of 10-15 times compared to unpressed straw i haystacks etc.
Straw briquettes have a heat value of app 17 MJ/kg.
It is very important that the bales are stored under shelter for protection against rain to maintain the moisture content in the range 10-15%. This ensures a good quality of briquettes that can be stored for several months without disengaging.
For this part of our solution we rely on strategic partners like Cormall, who for many years has specialised in handling and treating straw for different applications.
In order to make the straw ready for briquetting it has to be mixed and shredded to particles of 100-200 mm in length before entering a straw mill that reduces the particles down to a particle length of 10–20 mm.
A stone trap and a dust extraction device is important to reduce the wear on the hammermill and the briquetting press etc.
Briquetting of straw
Our BP5500HD and larger presses are very suitable for making straw briquettes due to their double feeding system.
For straw briquetting we offer a special version with enlarged inlet chamber, stronger compression motors, extra sensors, ventilated compression chamber with corrosion protection and special die system etc.
After mixing, shredding and milling the straw is fed into the press via a dosing silo or a special conveyor solution that ensures a steady material flow to the PLC controlled dosing screws that feeds the press with the optimal amount of straw depending on the expected end product.
In some cases 1-3% of liimestone is added to improve the strength of the briquettes as well as assisting in keeping the boiler clean.
Straw briquettes that has been briquetted and followingly grinded and freed from dust particles is found to be an excellent animal bedding that is able to suck up water until 5 times it's own weight.
Straw briquettes pressed with a high strength and density may also be used as 'toys for pigs' to keep them activated and out of internal fights.
For consumer briquttes from wheat or rape straw it may be necessary to add 0.8 to 1.5% lignin as well. We recommend Ø75 mm briquette dimension and cutiing with our hydraulic briquette breaker for this application.
However straw briquettes will produce 5-7% of ash, which is 10 times higher than the ash content for a good quality wood briquette.
Advantages of Straw Briquettes
- Straw is fast growing and available in large amounts
- Normally no need for drying
- Straw briquettes are CO2 neutral
- High bulk density of 500-600 kg/m3 means reduced transportation costs compared to baled straw