Evaluation of Bio-Oils Produced from Rapid Heating Pyrolysis of Palm Kernel Shell-Polymer Waste Mixtures

This study evaluated the yield, quality, combustion and emission characteristics of bio-oils from mixtures of palm kernel shell (PKS) and two polymer wastes (acrylonitrile butadiene styrene (ABS) and high-impact polystyrene (HIPS)) using a rapid heating pyrolysis process. Rapid heating pyrolysis was conducted in a fixed bed reactor at 650 ℃ with N2 gas. Each polymer waste was mixed with PKS at 0–30 wt%. The addition of polymer wastes into the PKS feedstock improved the bio-oil yield and quality in terms of gross calorific value, water content and acidity. Furthermore, the bio-oils from the ABS-PKS mixtures were blended to produce 5 wt% of bio-oil and 95 wt% B7 diesel fuels for light-duty diesel engine testing. All biofuels showed a decreasing trend in engine performance with increasing ABS composition by 1.29%–2.40%, respectively at 2600 rev/min compared to the benchmark B7. However, CO, CO2, UHC and NO emissions showed decreases of 0.5%–41.9%, 1.0%–16.4%, 13.8%–75.1% and 1.7%–13.6%, respectively with increasing ABS composition. The optimum biofuel was 30 wt% ABS in B7, whereby the CO, CO2, HC and NO had the greatest reductions of 41.9%, 16.4%, 13.8% and 13.6%, respectively, albeit with a 1.29% decrease in the highest power output.