Thermodynamic analysis of syngas production via chemical looping dry reforming of methane

Chemical looping dry reforming of methane (CL-DRM) for syngas production was studied based on thermodynamic equilibrium analysis under various fuel reactor temperatures and pressures. Fe2O3 was used as the oxygen carrier (OC). Four CL-DRM stages can be identified based on the ratio of circulated Fe2O3 flow rate to fed CH4 flow rate (OC/CH4): combined methane decomposition (MD) and partial oxidation of methane (POM), combined POM and complete oxidation of methane (COM) with POM dominance, combined POM and COM with COM dominance, and COM. For syngas production the OC/CH4 ratio must be small and its value depends on reaction temperature. Based on the results obtained, it was found that CH4 oxidation due to the presence of OC is the key reaction that affects CL-DRM performance. Compared with conventional DRM in which no OC was introduced, CL-DRM has advantages of producing higher CH4 conversion and lower carbon formation. However, lower CO2 conversion results. It was found that both conventional DRM and CL-DRM were not favourable as reaction pressure increases. The CH4 conversion in CL-DRM can be enhanced by increased CO2/CH4 ratio and water addition in the feedstock. However, CO2 conversion decreased due to increased CO2 amount or enhanced water gas shift reaction. (C) 2019 Elsevier Ltd. All rights reserved.