Benefits of Drying Fuel
• It depends on your process…
• Pelletizing requires drying
• Gasification and pyrolysis generally requires drying
• Not required for direct combustion, but can result in the following benefits:
• Improved efficiency: 5%-15%
• Increased steam production: 50%-60%
• Reduced ancillary power requirements
• Reduced fuel use
• Lower emissions
• Improved boiler operation
• An accurate and comprehensive cost/benefit analysis must be preformed!
Drawbacks of Using Dry Fuel
• Firing dry fuel can result in the following drawbacks:
• Flame temperature can approach the fusion temperature of the ash
• If drier is down must use fossil fuel backup in boiler
• May require expensive materials of construction if the hot flue
gases are cooled below the dew point
• Lower excess air tends to decrease NOx emissions, but high flame temperatures can increase NOx formation.
Typical / Mainstream Biomass Dryer Technologies
•Rotary Drum –Most Common for wood
•Belt/Conveyor –Second Most Common for wood
•Cascade/Fluidized Bed
•Flash /Pneumatic
•Superheated Steam
•Bed/Grate