Value-added fuels from the catalytic pyrolysis of Alternanthera philoxeroides

The pyrolysis of Alternanthera philoxeroides was performed in a semi-batch reactor under a constant temperature (450 °C), heating rate (50 °C min−1), and N2 flow rate (0.2 L min−1) to investigate the effects of SnCl2, Al2O3.4SiO2·H2O, and MoS2 amount (1, 1.25, 1.50, 1.75 and 2 wt%) on the pyrolysis oil, biochar, and gas yield. The catalysts not only gave higher pyrolysis oil yield (24.89, 24.74, and 29.47 wt%) but also improved the fuel properties [oxygen, water, acid content, viscosity, and high heating value (8.88 to 9.38 MJ kg−1)]. The pyrolysis oils and biochars were analyzed by CHNS/O, FT-IR, GC–MS, 1H NMR, SEM-EDX, XRD, and porosity analyzer. The SnCl2 and MoS2 enhanced the concentration of phenolic (17.02%), paraffinic (12.74%), naphthenic (5.13%), aromatic (18.06%), and olefinic (7.96%) compounds in pyrolysis oils that matched the carbon chain length (C2 to C24) of petroleum fuels. The catalysts improved the high heating value (20.75 to 21.30 MJ kg−1) of biochars by reducing the oxygen content from 36.84 to 38.29 wt%. Only SnCl2 and Al2O3.4SiO2·H2O at 2 wt% gave maximum H2 (11.83 mol. %) and CH4 (8.11 mol. %) yield and enhanced the gross calorific value of the pyrolysis–gas to 14.41 MJ m−3.