Effect of Polyethylene Terephthalate (PET) Addition on Catalytic Pyrolysis of Crude Palm Oil (CPO) over Ni/Al-MCM-41

Abstract

Rapid global population growth continues to escalate worldwide energy demand, while finite fossil fuel reserves are depleting at an unprecedented pace. Concurrently, the accumulation of non-biodegradable plastic solid waste represents an urgent environmental concern. Catalytic co-pyrolysis of crude palm oil (CPO) and waste polyethylene terephthalate (PET) offers an attractive thermochemical pathway to simultaneously valorize bio-based resources and polymer waste into high-quality liquid biofuels. In this study, the catalytic co-pyrolysis of CPO and PET was investigated over a synthesized mesoporous Ni/Al-MCM-41 catalyst across varied CPO:PET mass ratios (1:0, 2:1, 1:1, 1:2, and 0:1). The catalyst was characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), N2 physisorption (BET), and temperature-programmed desorption of ammonia (NH3-TPD). Gas chromatography–mass spectrometry (GC-MS) analysis revealed that the 1:1 CPO:PET mass ratio was optimal for biogasoline synthesis, producing the highest gasoline-range hydrocarbon fraction (C7–C12) of 44.72% w/w with an aliphatic selectivity of 25.33% w/w. Physicochemical fuel characterization demonstrated that although the measured density (0.872 g/cm³) slightly exceeds the limits specified by the Indonesian National Standard (SNI 3506:2017) for direct standalone automotive use, its favorable kinematic viscosity (0.999 mm²/s), high calorific value (9,369 kcal/kg), and outstanding Research Octane Number (RON 101.9) demonstrate excellent viability as a high-octane renewable blending component for commercial gasoline.