Document Type


Publication Date



The global consumption of plastics has soared in the past 50 years culminating a total of 380 million tons of polymers generated in 2015. 80.5% of this plastic was disposed of or burned, leaving only the remaining 19.5% to be recycled, primarily through mechanical means. This is far from sustainable and chemical recycling can be turned to as a solution. In this study, the pyrolysis of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) has been carried out in a single and double-stage mechanically fluidized reactor using continuous regime to create viable fuel replacements and high-value industrial components. Blends of the plastics at varying ratios were also tested to emulate mixed plastic waste. A temperature range of 550 – 770 oC was used un the single-stage experiments, while the double-stage experiments added a furnace downstream of the reactor at 800 oC. To characterize the liquid and gaseous products collected, four techniques were used, namely: Gas-Chromatography Mass-Spectroscopy (GC-MS), Micro Gas-Chromatography (Micro-GC), Karl Fischer Titration, and Bomb Calorimetry. The results gathered proved that the oil and gas products are suitable for replacing or mixing with conventional diesel and gasoline. The products, more so those from double-stage pyrolysis, are also applicable for further industrial processing to monomers where they can be repolymerized into new PE. Plastic blends have demonstrated synergism leading to both higher liquid yields, and the highest energy content of 46.5 MJ kg-1. Overall, the process consumes 97.4% less energy than it produces making the pyrolysis of plastics a viable route to sustainable energy and chemicals.