The forms of active sites of Fe/Ca/Ni@C catalyst for the reforming of volatiles of biomass pyrolysis under N2 and CO2 atmosphere

Char-supported Fe/Ca/Ni catalysts were tested in a fixed-bed reactor at 600 degrees C for reforming of volatiles derived from biomass pyrolysis. The effect of atmosphere on the distribution of production was investigated, and it was found that char-based 5Fe1.5Ca catalyst (5Fe1.5Ca@C) can remove heavy oil from 1.71 wt% (raw) to 0.16 wt% (5Fe1.5Ca@C) under N-2 atmosphere. The char-based 5Fe1.5Ca0.8Ni (5Fe1.5Ca0.8Ni@C) catalyst showed the same effect on heavy oil, from 1.74 wt% (raw) to 0.70 wt% (5Fe1.5Ca0.8Ni@C), and the maximum H-2 yield (281.29 mL/g) and CO yield (349.47 mL/g) are obtained at 5 % CO2 atmosphere. XRD and TPR characterization indicated that CaO, FeNi3, Fe2O3, CaCO3, and Ca2Fe2O5 were finely formed, Fe/Ni/Ca@C catalysts in their oxide states were also investigated for the reforming of tar. Ca species was found no catalytic activity for the reforming of volatiles at the pure CO2 atmosphere, but Fe/Ca/Ni@C catalyst system with suitable activities at a pure N-2 and 5 % CO2 atmosphere. The CaO is reacted to CO2 in the atmosphere forms CaCO3. Ca in its oxide metallic forms rather than its carbonate forms was considered the active site for reforming the volatiles.