Simulation of pyrolysis process for waste plastics using Aspen Plus: Performance and emission analysis of PPO-diesel and PPO-biodiesel blends

As the global population increases, so does the usage of plastics in households, water bottles, and garbage bags, posing significant environmental threats. Plastics, being inorganic waste with long degradation periods, contaminate air, water, and soil when disposed of in landfills. Given the rise in global plastic production, effective waste management strategies are essential. This study utilized Aspen Plus simulation to analyze the pyrolysis process of waste plastics, specifically PE, PS, and LDPE. Simulations were conducted with temperature variations between 350°C to 550°C to determine the optimum conditions. Additionally, the study compared engine performance and emissions using mixtures of plastic pyrolysis oil (PPO), biodiesel from waste cooking oil (WCO), and diesel. Engine performance tests were conducted with variations in engine speed and load for PPO-diesel and PPO-biodiesel mixtures. Simulation results showed that the optimal pyrolysis temperature for the highest PPO yield was 450°C, producing 89% for PS plastic. Pyrolysis at 500°C yielded 85% oil for PE, 83% for LDPE, and 60% for mixed plastics. Engine performance tests indicated that adding PPO to diesel and WCO biodiesel significantly affected engine performance and emissions. A 5% PPO blend in diesel demonstrated better brake thermal efficiency and lower BSFC compared to higher PPO blends.