Generation of liquid fuels through the pyrolysis process from polypropylene and polystyrene for energy utilization

Abstract

To valorize polypropylene (PP) y polystyrene (PS) waste by generating liquid fuels, a pyrolysis process was conducted using a horizontal fixed-bed Shaftherm reactor. Temperature ramps of 500, 600, y 700°C with times of 60, 90, y 120 minutes were used. At temperatures below 500°C, the process was incomplete, yielding only melted polymer. Starting from 500°C, the process was complete, improving with reaction time. For PP, a liquid fraction yield of 56,97% at 500°C y 60 minutes was recovered, increasing to 86,64% at 700°C. For PS, the best yields were obtained at 600°C, with recoveries between 90,36% y 92,63% at 90 minutes. The liquid fractions from PP at 500°C, containing C2-C10 hydrocarbons, resemble commercial extra gasoline C4-C10, while the PS fractions are rich in styrene y C2-C18 chains. Highlighting their high energy potential, PP showed a calorific value between 42 236,64 kJ/kg y 45 005,34 kJ/kg, y PS between 37 401,38 kJ/kg y 43 107,50 kJ/kg. The comparative analysis of the calorific value between the generated liquid fractions y commercial fuels (diésel y gasoline) demonstrated that the obtained products have high potential as energy sources, with PP having a higher calorific value than diésel y extra gasoline. Quality results, such as density y viscosity, were encouraging for industrial applications, y chromatographic analysis revealed the presence of valuable compounds, suggesting their potential use in the chemical industry. Although some parameters did not meet INEN standards, the liquid fractions show significant similarities with commercial fuels, suggesting their viability as an alternative energy source.