Syngas production via chemical looping reforming using methane-based feed and NiO/Al2O3 oxygen carrier

Syngas production based on chemical looping reforming was experimentally studied using a fixed-bead reactor. The 15 wt% NiO/Al2O3 was used as the oxygen carrier. The reaction temperature was fixed as 800 °C. For reactant containing CH4 only, it was termed as chemical looping partial oxidation of methane (CL-POM). With five CL-POM cycles, no decay in oxygen carrier activity was found. A high H2/CO ratio resulted due to dominant H2 production reactions in the reduction stage. Carbon deposition on the oxygen carrier surface can be identified from the CO and CO2 formations in the oxidation stage. With CO2 added in the reactant in addition to CH4, this was referred to as the chemical looping dry reforming of methane (CL-DRM). Near theoretical amounts of H2 and CO yields were obtained. With both H2O and CO2 added in the reactant in addition to CH4, this was referred to as the chemical looping tri-reforming of methane (CL-TRM). Due to coupled steam reforming of methane (SRM), POM, and DRM, higher CH4 conversion, H2 and CO yields resulted compared with the CL-POM and CL-DRM cases. The average H2/CO ratio of 1.2 was obtained with reactant with molar ratio of CH4/CO2/H2O = 1/1/1.