Upgradation, product analysis and engine performance of hydrocarbon fuels produced through pyrolysis of thermoplastic polymers with Si and ZSM-5 modified catalysts

Abstract

Waste plastic mitigation is one of the major concerns for achieving a sustainable environment. The present study reported the conversion of mixed waste plastics into hydrocarbon fuels through catalytic pyrolysis using DOL, SiDOL, ZSM-5, and ZSMDOL catalysts. Doping of Si and ZSM-5 enhanced the surface area as well as improved catalytic activity. The NMR analysis confirmed that pyro-oil contains 8.31–12.61, 17.53–29.12, and 62.38–69.86 (v/v)% of aromatics, olefins, and paraffin's hydrocarbons, respectively. FTIR analysis identified the presence of alkane, alkene, and aromatic hydrocarbons. The mass spectroscopy analysis revealed that pyro-oil contained a lower range (<C12) of hydrocarbon (up to ∼89%) when the catalyst was used. The fluidity properties such as density, viscosity, and pour point were reduced significantly in the catalytic pyro-oil due to the further cracking of intermediate hydrocarbons formed during the pyrolysis. The pour point was found to be the lowest (below -40 °C) for pyro-oil obtained with ZSM-5 catalyst. The highest calorific values of ∼50.9 MJ/kg and lowest carbon residues of ∼0.11 wt% were estimated for catalytic pyro-oils. The DI diesel engine performance showed that catalytic pyro-oils had better engine performance and combustion process compared to other fuels. Also, the emissions of harmful gases such as CO, HC, and NOx were found to be lower than commercial diesel when pyro-oil was blended with CD.