Synthesis and Characterization of Liquid Fuel from PP and PS waste via Catalytic Pyrolysis
Creators: name: Tihitna, Abebe
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2018

description: Catalytic Pyrolysis of polypropylene (PP) and Polystyrene (PS) into fuel like products using silica alumina catalyst that extracted from rice husk was investigated over temperature range of 430-470°C.Burning rice husk at 700 By:-Tihitna Abebe o C for 2hrs give rice husk ash and washed and dry at 800 C for 1 hour.Finally the dried silica mixed with aluminum oxide using dry-dry mixing and calcined for 1 hour at 800 o C.The prepared catalyst was used for catalytic pyrolysis.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 (44.7%), gas (60.14%) and solid residue (43.4%) was achieved at 450°C with the use of 12.5gm catalyst amount for liquid oil and 5gm catalyst for gas and 470 o C with the use of 12.5gm of catalyst for solid residues.The pyrolysis time for high yield conversion of liquid oil and gaseous fraction were 30 minutes and 60 minutes pyrolysis time for solid residues in case of PP and liquid; 48.8% at 430 o C in the presence of 12.5gm catalyst amount, gas; 78.286%, and residue; 52.4% at 450 o C and 470 o C for gaseous and residue in the presence of 12.5gm catalyst for solid residue and 5gm catalyst for gaseous fraction at 30 minutes pyrolysis time for liquid product and gaseous fraction and 60 minutes for residue in case of PS.At higher catalyst amount and lower degradation temperature for PS and moderate for PP with lower residence time the yield of the liquid fuel was higher in both plastic type.The high yield of solid residues (char) and gaseous product was mainly due small cross section of heating, inefficiency of the pyrolyzer and insufficient condenser.Raw waste plastics were analyzed by FTIR.The FTIR spectrum indicates there was a presence of Naphtalenes, Olefins, and Amine, Acid group in both plastic type and Aromatics in PS.The catalyst silica alumina that was used for catalytic pyrolysis analyzed by XRD.XRD graph shows both silica and alumina exist.In addition to this the graph show that the catalyst had amorphous structure.The liquid fractions were analyzed by GC/MS.The results showed that the waste plastics of polypropylene liquid oil consisted of a range of hydrocarbon mainly in Gasoline range (C 5 -C ) and liquid oil from catalytic pyrolysis of polystyrene waste consisted a wide range of hydrocarbons mainly distributed within the C 12 5 –C that was in the range of gasoline, diesel and heavy oil.The liquid product obtained in case of Polypropylene was enriched in the naphtalenes hydrocarbons.Similarly,the liquid product obtained in case of polystyrene was enriched in styrene hydrocarbons with prevalence in gasoline,diesel and heavy oil range hydrocarbons.The liquid fraction that had high yield for both plastic type were also analyzed for fuel properties.Conclusion from the study,liquid oil from PP waste had a lower yield (44.7), density (0.827g/cm 3 27 ), viscosity (2.06cSt) and a higher value of flash point (29 C) and calorific value (25mJ/Kg) than liquid oil (0.955g/cm 3 , 2.2cSt, 29 o C, 20mJ/Kg) from PS waste.Generally the whole results indicated that the derived liquid fractions were fuel-like meeting the fuel grade criteria.