Characteristic and mechanistic study of enhanced carbon-based synfuel from biomass and coal by magnetite additive for synergistic co-carbonization technology

Biomass is a renewable and potentially carbon-neutral energy source and can be a promising alternative to fossil fuels in the ironmaking industry. The co-carbonization technology of biomass and coal for high-quality biofuel production has great potential. This study investigated the effects of the addition of magnetite (Fe3O4) on the physicochemical properties and combustion performance of wood shavings (WS) and bituminous coal (BC) (WS/BC = 4/6) sintered with a carbon-based synfuel. The results indicate that increasing the proportion of 2 wt% Fe3O4 can increase the high calorific value to 34.60 MJ kg−1 and the maximum combustion rate temperature reaches 469 °C, however, increasing the proportion decreases the burnout temperature to 575 °C, and the activation energy of the rapid pyrolysis stage decreases to 43.54 kJ mol−1. In addition, the activation energies of WS/BC char in the fast co-pyrolysis stage and the combustion reaction decrease significantly to 43.54 kJ mol−1 and 92.96 kJ mol−1, respectively, with the addition of 2 wt% Fe3O4. The area ratio of the fitted aromatic C−O reaches 79.91 %. Fe3O4 can form active centers on the surface of a carbon-based synfuel, improving the stability and orderliness of the fuel. The catalysis of the Fe3O4 additive with macromolecular organic compounds involves mainly oxygen-containing functional groups, promoting the cleavage of C−C bonds connected to oxygen-containing functional groups. In general, these results provide certain theoretical guidance for the preparation and application of sintered carbon-based synfuels.