The aim of this study is to explore catalytic microwave pyrolysis of lignin for renewable phenols and fuels using activated carbon (AC) as a catalyst. A central composite experimental design (CCD) was used to optimize the reaction condition. The effects of reaction temperature and weight hourly space velocity (WHSV, h(-1)) on product yields were investigated. GC/MS analysis showed that the main chemical compounds of bio-oils were phenols, guaiacols, hydrocarbons and esters, most of which were ranged from 71% to 87% of the bio-oils depending on different reaction conditions. Bio-oils with high concentrations of phenol (45% in the bio-oil) were obtained. The calorific value analysis revealed that the high heating values (HHV) of the lignin-derived biochars were from 20.4 to 24.5 MJ/kg in comparison with raw lignin (19 MJ/kg). The reaction mechanism of this process was analyzed.
Keywords: Activated carbon; Catalytic pyrolysis; Lignin; Phenols; Reaction mechanism.
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