In response to the growing environmental challenges associated with plastic waste management, the production of alternative fuels through pyrolysis emerges as a promising solution. This study evaluates the conversion of low-density polyethylene (LDPE) and polystyrene (PS) into liquid fuels using two pyrolysis systems equipped with a coaxial condenser (unit 1) and a tubular condenser (unit 2), respectively. The main objective is to compare their performance in terms of oil yield and the quality of the resulting products. The results indicate that the system equipped with a tubular condenser delivers better performance in terms of yield. Specifically, the pyrolysis of 1000 g of LDPE resulted in oil yields ranging from 76.2% to 79.4% ± 2.2 for units 1 and 2, respectively. In comparison, PS pyrolysis produced lower yields of 65.7% and 64.9% ± 0.5 for the same units. Physicochemical analysis of pyrolysis oils revealed properties similar to those of commercial diesel fuel. These oils have several characteristics that comply with Cameroonian standards, European standard EN 590, and ASTM standard D7544, particularly with regard to sulfur content, acid number, gross calorific value, cetane number, cloud point, and pour point. In fact, for oil produced by LDPE pyrolysis in Unit 2, the higher heating value (HHV) was 55.3 MJ/kg (compared to 42-45 MJ/kg for EN 590) and the cetane number was 52.4 (compared to >46 for EN 590). However, certain parameters did not meet industry standards, notably the flash point at 37.0°C (compared to >55°C for EN 590) and the viscosity at 1.101 mm²/s (compared to 2.0-4.5 mm²/s). These non-conformities are the main reason why fractional distillation is proposed to refine the products. This study makes a significant contribution to the development of pyrolysis systems tailored for plastic waste recovery, offering practical insights for large-scale implementation and reinforcing the potential of alternative fuels in the energy transition.
Djoukouo et al. (Sun,) studied this question.