Chiang Mai Journal of Science

     The conversion of waste plastics into oil through pyrolysis presents a promising alternative energy solution, addressing the significant environmental challenge posed by the accumulation of plastic waste. Despite numerous studies in this field, few have specifically focused on the design of a pyrolysis reactor incorporating six condensers connected in series. This research aimed to investigate the influence of waste plastic type through the pyrolysis process on product yield from three types of plastic waste: polypropylene (PP), high-density polyethylene (HDPE), and multilayer plastic (ML). Pyrolysis was performed in a 50 L household reactor for a reaction time of 90 min with the heating rate of 10-15 °C/min. The results showed that the pyrolysis process produced three types of products: liquid, solid, and non-condensable gases, with liquid being the main product. The experimental results indicated that the plastic pyrolysis reactor produced the highest proportion of liquid product, followed by non-condensable gases, with only a small amount of solid residue. The liquid product yield was highest in HDPE at 82.1%, followed by PP at 74.4% and ML at 47.1%. The non-condensable gases yields were 17.8%, 25.0%, and 42.9%, respectively. The DGC technique verified the fuel properties, confirming the presence of kerosene, naphtha, diesel, and fuel oil in the chemical composition. This experiment showed that pyrolysis of plastic waste in a reactor with a fractional condensation system could generate liquid fuel oil. It offers a potential framework for the production of liquid fuel that can be used as a substitute for fossil fuels.