Abstract
This study evaluates the combined techno-chemical and socio-impact relevance of converting jojoba residue into bio-oil using ZnO as an in-situ catalyst. Experiments were performed in a bench-scale, electrically heated fixed-bed batch reactor under nitrogen with a water-cooled condensation train. Five runs were conducted using 500 g feed charges: 500 °C with 0, 3, 5, and 7 g ZnO, and a 600 °C non-catalytic run to isolate temperature effects. Product yields were quantified as bio-oil, biochar, and non-condensable gas via mass balance, and bio-oils were qualitatively characterized by Gas Chromatography-Mass Spectrometry (GC-MS). At 500 °C, bio-oil yield was 16.6–16.8 wt% for 0–3 g ZnO, increased to a maximum of 26.6 wt% at 5 g ZnO, and then decreased to 22.2 wt% at 7 g ZnO, indicating an optimum catalyst-to-biomass ratio. Increasing the temperature to 600 °C (0 g ZnO) raised the bio-oil yield to 33.4 wt%. GC–MS results show that the intermediate ZnO loading produced a more distributed chromatographic profile compared with the non-catalytic and high-loading cases, consistent with more favorable vapor upgrading, while the 600 °C control exhibited stronger early/mid-retention contributions consistent with enhanced cracking to lighter volatiles. Overall, tuning ZnO dosage and temperature improved bio-oil yield and produced a more upgrade-friendly composition, pending fuel-property testing.
