KINETIC-BEHAVIOR OF SOLID PARTICLE IN CHEMICAL-LOOPING COMBUSTION - SUPPRESSING CARBON DEPOSITION IN REDUCTION

In order to apply chemical-looping combustion to a practical power pla nt, carbon deposition on the solid particle is one of the key problems to be overcome. Six kinds of solid particles were examined to clarify the kinetic behavior of carbon deposition. The effects of the solid c omposition, feed gas composition, and reaction temperature on carbon d eposition were investigated by TGR (thermogravimetrical reactor) on th e basis of NiO/YSZ particle. From the viewpoints of both reactivity an d resistance against carbon deposition, the particle of NiO mixed with YSZ (i.e., yttria-stabilized zirconia) was found to be a good candida te for chemical-looping combustion. We have observed that carbon depos ition could be completely avoided with very low concentration of water vapor. By means of a proposed model, the condition that carbon deposi tion would be avoided was identified.