Synthesis and characteristics of carbon-based synfuel from biomass and coal powder by synergistic co-carbonization technology

A synergistic co-carbonization method based on the use of corn stalk (CS), wood shavings (WS) and bituminous coal (BC) is proposed as a green and low-cost technology. The preparation parameters included a co-carbonization temperature of 600 °C, a co-carbonization time of 30 min, and a biomass/coal ratio of 4/6. The high calorific value (HCV) and bulk density of the CS/BC synfuel were 29.81 MJ kg−1 and 495 kg m−3, respectively, and those of the WS/BC synfuel were 30.11 MJ kg−1 and 485 kg m−3, respectively. The results indicated that the microcrystalline structure was ordered and that the proportion of the graphitic structure increased during the synergistic co-carbonization process. In addition, the co-carbonization process changed the contents of the functional groups on the surface. The amount of aromatic C–O increased during the synergistic co-carbonization process. Decreases in the O-containing functional groups and increases in the graphitic carbon content in the synfuel demonstrated that the interactions of the biomass volatiles with the bituminous coal generated a more regular structure for the carbon-based synfuel and changed the carbon type of the synfuel. This work provides a mechanism for the biomass and coal interactions occurring during the preparation of carbon-based synfuels.