Supplied Oxygen Properties of NiO/NiAl2O4 in Chemical Looping Re-Forming of Biomass Pyrolysis Gas: The Influence of Synthesis Method

In this paper, the oxygen supplied properties of NiO/NiAl2O4 synthesized via different methods were investigated. Imp OCs showed the highest effective oxygen amounts of 14.08% (9.32%(NiO) and 4.76% (NiAl2O4)) and medium oxygen releasing rate via CO-TGA. The O transfer rate of OCs synthesized with the precipitation method is slow due to the big particle size. The supplied oxygen content is much less at the first stage for OCs, because NiO is inside the NiAl2O4, and the strong interaction is between NiO and NiAl2O4. The supplied O rate of Imp OCs is proper (not too fast or too slow) due to the uniform distribution and moderate particle size of NiO, and there is a proper interaction between NiO and NiAl2O4. The CH4 chemical looping re-forming varied from the full oxidation (CH4 → CO2) to partial oxidation (CH4 → CO) followed by cleavage reaction (CH4 → H2 + C), depending on the content of effective supplied oxygen amount in OCs. Moreover, it also proved that CO-TGA and CH4 chemical looping re-forming in the fixed bed are two effective methods for analyzing the supplied oxygen properties of OCs.