Preliminary experimental performance of a solar biomass briquette drier

This paper reports on the experimental performance of a solar biomass briquette drier. The biomass briquette production process involves soaking biomass in water to soften and activate lignin. This moisture also acts as a lubricant during the compaction stage. Previous work has shown that maximum biomass density after compaction is attained for moisture content around 25%. However, this amount of moisture prevents proper combustion of the briquettes. Drying of briquettes is therefore necessary to ensure efficient combustion and maximize heating value. An indirect solar biomass briquette drier with 250 briquettes drying capacity was constructed based on a design developed and simulated using Computational Fluid Dynamics (CFD) in 2010. A delta shaped flat panel solar collector was implemented in this design to maximize solar energy capture. The design was in response to a South African community based biomass briquette producing project. The project currently utilizes electric oven and open-sun drying; open sun drying has low effectiveness; while oven drying is expensive and nonrenewable. Experimental tests obtained average collector temperature of 53 °C and average air temperature rise of 16 °C for an average spring time ambient temperature of 20 °C and average insolation of 894 W/m2. These results were in good agreement with CFD predictions made at the design stage. Average drying time was recorded to be 16 hours of sunlight for 30% moisture content. These results clearly show the viability of this method for drying biomass briquettes.