Synthesis and optimization of CuxNi0.6-xMn0.4Fe2O4 oxygen carrier for chemical looping steam methane reforming

Abstract

ABSTRACT The self-supported CuxNi0.6-xMn0.4Fe2O4 oxygen carrier (x = 0.1–0.5) is synthesized to be applied in the chemical looping steam methane reforming (CL-SMR) process through the synthesized co-precipitation method. The response surface methodology (RSM) based on the Box–Behnken model is adopted to evaluate the effects of independent variables on the functionality of responses as well as predicting the best response volume. In this method, the variables consisting of reaction temperature (550–700°C), oxygen carrier (OC) loading percentage (0.1–0.5), steam-to-CH4 ratio (S/C), (1.5–3.5), and redox cycles’ count (10–24) and the responses consisting of hydrogen (H2) production yield, CH4 conversion percentage, and CO/CO2 molar ratio are assessed. The analysis of variance (ANOVA) results indicate that the temperature reaction and the OC type are the most effective parameter, while the redox cycles’ count has the least effect on CH4 conversion percentage and produced H2 yield. The obtained optimization results in the laboratory conditions indicate that the self-supported Cu0.3Ni0.3Mn0.4Fe2O4 OC in the operational conditions of 650°C, S/C = 2.5, and redox cycle = 24 are the best responses for H2 production yield, CH4 conversion percentage, and CO/CO2 molar ratio with 80.9, 99.6, and 9.7, respectively. The material structure and the functional groups are assessed through X-ray diffraction pattern (XRD) and Fourier transform infrared spectroscopy (FT-IR) respectively. The morphology and particles’ size are analyzed through FESEM through EDX whereas the OC-specific surface area analyses are carried out by BET.