Pyrolysis liquid fuel production from waste plastics using spherical-shape zeolite catalyst

A novel spherical zeolite catalyst was synthesized and used in the pyrolysis process to produce liquid fuel from waste polyethylene terephthalate (PET) and high-density polyethylene (HDPE). Inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray diffractometer (XRD), and scanning electron microscopy (SEM) were used to characterize the synthesized spherical-shaped zeolite (SSZ) particles. Liquid fuels produced from the pyrolysis of individual and mixed waste plastics with or without SSZ catalyst were analyzed. When the SSZ catalyst was used, the yield of pyrolysis oil from PET increased from 38.1 % to 43.5 %, whereas it increased from 72.8 % to 84.6 % HDPE. For PET:HDPE mixed feedstock, the yield decreased from 78.5 % to 65.3 % as the PET:HDPE weight ratio was changed from 1:4–4:1 at an optimal temperature of 425°C and feedstock:SSZ catalyst ratio of 10:1. The pyrolysis liquid products were analyzed using Fourier-transform infrared (FTIR) spectroscopy, and Thermogravimetric analysis (TGA). In the analysis of engine performance, the liquid fuel obtained from PET exhibited the highest average brake torque and power output. The specific fuel consumption decreased with increasing engine speed for all fuels. This research demonstrates the potential of SSZ catalytic pyrolysis as an effective method to produce liquid fuel products from waste plastics, thereby addressing both the environmental issues associated with waste plastics and the growing demand for petroleum-based fuels.