Potential of Bio-Oil from Rice Husk and Sawdust Pyrolysis as a Liquid Organic Hydrogen Carrier (LOHC)

Biomass represents a renewable and abundantly available energy resource; however, several residues, including rice husks and teak sawdust, remain underutilized. Their distinct physicochemical characteristics influence thermal decomposition behavior, making fast pyrolysis a promising pathway for producing higher-quality bio-oil. This study investigated the effect of varying mixtures of rice husks and teak wood on bio-oil yield and properties using a fixed-bed reactor operated at 500 °C with LPG as the heat source. The resulting bio-oil was characterized in terms of moisture content, pH, viscosity, higher heating value, elemental composition (C–H–O), atomic O/C and H/C ratios, and chemical compound distribution via GC–MS analysis. The results demonstrate that increasing the teak wood fraction consistently enhanced bio-oil performance. Product yield increased from 39.6% to 54%, moisture content decreased from 30% to 20%, and the calorific value improved from 17.5 to 19 MJ/kg. A reduction in the O/C ratio from 0.50 to 0.32 indicates significant deoxygenation, accompanied by a compositional shift from acid- and furan-rich compounds (typical of rice husks) toward more stable phenolic structures derived from teak lignin. The mixture containing 25% rice husks and 75% teak wood exhibited the most balanced performance. These findings confirm that fast pyrolysis effectively converts local biomass into cleaner, energy-dense liquid fuel and highlight its promising potential as a liquid organic hydrogen carrier (LOHC) for safer and more flexible hydrogen-based energy systems.