화학공학소재연구정보센터
Canadian Journal of Chemical Engineering, Vol.86, No.4, 756-767, 2008
The reaction of NiO/NiAl2O4 particles with alternating methane and oxygen
The reduction and oxidation behaviour of oxygen carrier particles of NiO and NiAl2O4 has been investigated in a fluidized bed reactor as well as a thermogravimetric analyzer (TGA). The particles showed high reactivity and gas yield to CO2 with methane in the temperature interval 750-950 degrees C. In the fluidized bed the yield to CO2 was between 90 and 99% using bed masses corresponding to 16-57 kg/MWfuel. Complementary experiments in a TGA at 750 and 950 degrees C showed a clear reaction of the NiAl2O4 with CH4 at the higher temperature. There was methane released from the reactor at high degrees of solid oxidation, which is likely associated with the lack of Ni-sites on the particles which can reform the methane. There was some carbon formation during the reduction, although the amount was minor when the gas yield to carbon dioxide and degree of oxidation of the solid was high. A simple reactor model using kinetic data from a previous study predicted the gas yield during the reduction in the fluidized bed experiments with reasonable accuracy. The oxygen carrier system investigated in this work shows high promise for use in a real CLC system, provided that the particle manufacturing process can be scaled up with reasonable cost.