Effects of feedstock pretreatment and binder selection on briquette characterization

Briquettes from raw biomass exhibit smokiness and emits irritant gases. Technical solutions were found in feedstock pretreatment and appropriate binder selection, which this study investigated. Torrefaction and fermentation pretreatments and used printing paper (UPP), newsprint (Np), and clay (C) were selected for experimentation. Samples of Gmelina arborea sawdust (GaS) collected from sawmills were characterized using the ASTM standards. Hollow briquettes were produced at 10:90%, 20:80%, 30:70%, 40:60%, and 50:50% feedstock/binder mixes. Data were analyzed using descriptive statistics and ANOVA at α0.05. Results showed that torrefaction yield increased with torrefaction time, particle density increased with fermentation time but decreased with torrefaction time. Proximate values significantly differ for torrefied and fermented GaS, while heating value (HHV) increased with residence for torrefied and fermented briquettes. Torrefied UPP briquettes produced non-luminous flame and less smoke. Clay briquettes, however, had charred combustion. Fuel consumption increased with binder concentration but decreased with an increase in residence time.