Effect of biomass particle size on yield and composition of bio-oil produced from Empty Palm Fruit Bunch

Abstract Empty palm fruit bunch (EPFB), a byproduct of palm oil processing, can be used efficiently to produce renewable energy-rich products, thus stimulating a cleaner environment. In this study, the pyrolysis production of bio-oil and biochar was performed in a fixed bed reactor by depolymerizing the primary components of the EPFB biomass (cellulose, hemicellulose and lignin) using biomass particle size of 0.30 mm, 0.60 mm and 1.0 mm. Increasing the biomass particle size to 0.6 mm (600µm) from 0.3mm (300µm), resulted to a bio-oil increased yield of 4.7 wt.%. A further particle size increase to 1.0 mm (1000µm), reduced the bio-oil output by about 2.8 wt.%. Low heating rates and mass transfer limitations for biomass particles larger than 0.6mm relative to smaller particles impacted the production of the heavier components through the reduction in generation of volatile products, resulting in a decreased bio-oil yield. Biomass's particle sizes substantially affected the pyrolyzed products distribution. With proper characterization the stabilization and upgrading of the crude bio-oil can be improved and bio-oil utilized as a renewable fuel and for platform chemical extraction. Comprehensive chemical, structural and morphological analyzes of the EPFB biomass and pyrolyzed products were performed using Ultimate and Proximate analytical method and several other characterization techniques to elucidate the biomass and products composition and characteristics as fossil derived fuel substitute. The result of chemical analysis showed that the produced bio-oil has a high energy density but very viscous (3.4mm/s) and highly corrosive (pH of 2.6), probably due to the high concentration of carboxylic acids, phenols and phenolic. Bio-oil is inferior to diesel fuel due to its high flash point, low pH, high oxygen concentration, and high viscosity. However, it can be upgraded and be utilized as a sustainable renewable fuel and for extraction of platform chemical.