Valorization and physicochemical characterization of municipal solid waste gasification tar derived aliphatic hydrocarbon-rich oils

BACKGROUND AND OBJECTIVES: Municipal solid waste gasification generates tar as a persistent by-product, posing operational and environmental challenges due to its viscosity, instability, and high content of various hydrocarbons. Previous studies demonstrated that the principal constituents of tar were predominantly aliphatic hydrocarbon compounds. The study objectives were to investigate the valorization potential and evaluate the physicochemical properties of the oil fraction derived from tar waste through pyrolysis process from gasification plant of Surakarta landfill, Indonesia. METHODS: Conversion of tar into aliphatic hydrocarbon-rich oils using a sequential re-pyrolysis method at temperatures ranging from ۳۵۰–۷۰۰ degrees Celsius. The physical properties of the pyrolysis products, specifically temperature, viscosity, and density, were determined, while their chemical compositions were evaluated using gas chromatography and infrared spectroscopy. The results of the physicochemical tests were then analyzed and evaluated with those of commercial oil products.FINDINGS: Pyrolysis produced three liquid fractions based on the sequential re- pyrolysis: tar pyrolysis ۱, ۲, and ۳. Liquid yields of approximately ۶۵–۷۰ weight percent at ۵۰۰–۵۵۰ degrees Celsius. Mass spectrometry analysis revealed aliphatic hydrocarbons (alkane–alkene) contents of ۸۶.۶۵, ۴۵.۵۸, and ۴۶.۷۶ percent in tar pyrolysis oil-۱, ۲, and ۳ samples. The identified aliphatic hydrocarbons ranged from ۸–۲۱, ۱۲–۴۳, and ۹–۲۰ carbon atoms in the respective fractions. The infrared spectra consistently displayed characteristic aliphatic carbon-hydrogen stretching vibrations, thereby confirming that the resulting products are rich in aliphatic hydrocarbons. The produced oils exhibited densities of ۸۰۱.۳–۸۷۵.۴ kilograms per cubic meter and viscosities of ۲.۳۰۴–۲.۹۵۶ centistokes at ۴۰ degrees Celsius, indicating potential for liquid-fuel and hydrocarbon-material applications, although the relatively low flash point of ۴۰–۶۲ degrees celsius requires further upgrading for improved product stability.CONCLUSION: Sequential re-pyrolysis demonstrated the potential to convert tar into aliphatic hydrocarbon-rich oils, with tar pyrolysis oil-۳ showing the highest aliphatic hydrocarbon content (۸۶.۶۵ percent) and a C۸–C۲۱ carbon-chain range. The findings demonstrate that tar pyrolysis oil-۳ exhibits the highest aliphatic content among the evaluated products, suggesting its viability as an intermediate hydrocarbon feedstock for subsequent upgrading. Further fractionation, upgrading, and scale-up studies are required to determine its suitability for specific fuel or hydrocarbon-material applications.

کلیدواژه ها:

Aliphatic hydrocarbons oil ، municipal solid waste (MSW) gasification ، Physicochemical characterization ، sequential re-pyrolysis ، Tar valorization.