Reduction and oxidation kinetics of solid fuel chemical looping combustion over a core-shell structured nickel-based oxygen carrier: Application of a developed grain size distribution model

In this study, the feasibility for chemical looping combustion (CLC) with a solid fuel was investigated using a novel synthesized nickel-based oxygen carrier (OC) supported by zirconia-shelled gamma- alumina (35% NiO/Al2O3@Zr) in a TGA. The nickel-based OC was impregnated over an alumina support which was coated by mesoporous zirconia shell via core-shell method. A grain size distribution model (GSDM) was developed based on the prediction of an initial grain size distribution considering pore to sphere factor to describe the kinetics of reduction and oxidation reactions in CLC process with solid fuel. The crystalline phase and physical properties of the synthesized OC was obtained using XRD, and BET/BJH methods. The predicted fractional conversion over time of 35% NiO/Al2O3@Zr in reduction and oxidation reactions obtained by the GSDM correlated closely with the experimental data.