Influence of pyrolysis temperature on crude palm pyrolysis oil from fresh palm fruit bunches in a double-inclined screw reactor

Abstract

Thailand, one of the world's largest crude palm oil producers, faces increasing energy demands and dependence on fossil fuel imports. This study presents a novel application of a double-inclined screw reactor for the slow pyrolysis of fresh palm fruit bunches (FFB). The effects of temperature variation (400°C, 500°C, and 600°C) on product yields and pyrolysis oil properties were systematically analyzed. The results showed that higher temperatures increased pyrolysis gas production (27.3 % at 400°C to 31.95 % at 600°C) while reducing pyrolysis oil yield (25.2 % to 16.4 %) due to enhanced thermal cracking. Biochar yield slightly declined, whereas wood vinegar increased from 37.8 % to 42.5 %, indicating greater decomposition of cellulose and hemicellulose. The physicochemical analysis of pyrolysis oil revealed a lower heating value ranging from 38.2 to 39.2 MJ/kg. While 400°C provided the highest oil yield, it contained a higher proportion of oxygenated compounds, reducing stability. 500°C was identified as the optimal pyrolysis temperature, offering a balance between oil yield (21.9 %) and quality, with lower oxygen content, improved stability, and better combustion properties. These findings highlight the potential of FFB-derived crude pyrolysis oil as a promising alternative fuel. Furthermore, the use of a double-inclined screw reactor proved effective for producing high-quality bio-oil from palm-based biomass, offering a novel approach to sustainable energy production for continuous industrial applications.