Reduction kinetics of lanthanum ferrite perovskite for the production of synthesis gas by chemical-looping methane reforming

The reduction kinetics of LaFeO3 oxygen carrier for the production of synthesis gas by chemical-looping methane reforming (CLMR) is investigated in the present work. The stoichiometric relationship between oxygen carrier and methane in chemical-looping process is established by temperature programmed surface reaction (TPSR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) characterization. The effects of reduction conditions, namely, gas to solid molar ratio, temperature and sequential redox reaction on the oxygen carrier conversion are investigated. The results from Hancock and Sharp method suggest that the phase boundary control is likely to be dominant. The power law model (PLM), shrinking core model (SCM), as well as nucleation and nuclei growth model (NNGM) are considered to interpret the reduction kinetics of LaFeO3 with methane to synthesis gas. The obtained results show that the 2-D NNGM best describes the experimental data providing parameters with adequate statistical fitting indicators. The model validity is also verified by the data from continuous flow reaction and sequential redox cycles to simulate chemical-looping methane reforming process. The apparent activation energy is estimated and compared with values from the literature data. (C) 2016 Published by Elsevier Ltd.