Polystyrene Plastic Waste into Liquid Fuel Using Silica-Alumina Catalyst, Extracted from Rice Husk

Abstract

Catalytic Pyrolysis of Polystyrene (PS) into fuel like products using silica alumina catalyst that was extracted from rice husk was investigated over temperature range of 430–470°C. The output of catalytic pyrolysis was liquid oil, solid residues (char) and gaseous fraction. The product yields as a function of temperature, time and catalyst amount were studied. High conversion of liquid (48.8%) was achieved at 430 and 450ºC in the presence of 12.5 gm catalyst amount liquid. The pyrolysis time for high yield liquid and gas was 30 min and 60 min for residue. At higher catalyst amount and lower degradation temperature, the yield of the liquid fuel was higher. Raw waste plastic was analyzed by FTIR. The FTIR spectrum indicates that there was a presence of naphtalenes, olefins, and amine, acid and aromatics group in polystyrene plastic type. The liquid fractions were analyzed by GC/MS. The results showed that liquid oil from the catalytic pyrolysis of polystyrene plastic waste was enriched in styrene and consisted of a wide range of hydrocarbons mainly distributed within the C5–C27 that was in the range of gasoline, diesel and heavy oil. The liquid fraction that had high yield for PS plastic type was analyzed for fuel properties. From the study, liquid oil from PS waste had a density (0.955 g/cm3), viscosity (2.2 cSt) and a higher value of flash point (29°C) and calorific value (20 mJ/kg) from PS waste. From the study, conversion of waste polystyrene plastic in to liquid fuel using catalyst extracted from rice husk is a possible method to minimize environmental problems due waste plastic and rice husk.