Syngas combustion characteristics of four oxygen carrier particles for chemical-looping combustion in a batch fluidized bed reactor

Syngas combustion characteristics of oxygen carrier particles have been investigated. Experiments were performed on four oxygen carrier particles in a fluidized bed reactor. All four oxygen carrier particles showed high gas conversion, high CO2 selectivity, and low CO concentration in the reducer and very low NOx (NO, NO2, N2O) emissions in the oxidizer. Moreover, all particles showed good regeneration ability during successive reduction-oxidation cyclic tests up to the 10th cycle. The results indicate that inherent CO2 separation, NOx-free combustion, and long-term operation without reactivity decay of oxygen carrier particles are possible in a syngas fueled chemical-looping combustion system with NiO/bentonite, NiO/NiAl2O4, CoxOy/CoAl2O4, and OCN-650 particles. However, CoxOy/CoAl2O4 represented slight decay of oxidation reactivity with the number of cycles increased and the oxidation rate slower than other particles.