The thermodynamic evaluation and process simulation of the chemical looping steam methane reforming of mixed iron oxides

Steam reforming chemical looping (CL-SMR) using mixed iron oxides has the potential as an alternative to the current partial oxidation (POX) and steam reforming (SMR) processes. In this study, the use of FeMoO(4), Fe(2)ZnO(4) and Fe(2)MnO(4) as oxygen carriers (OC) under the CL-SMR reaction scheme was proposed to overcome the current disadvantages of methane POX and SMR processes. This research is aimed at finding potential iron-based metal oxides for the production of syngas, which can be regenerated under favorable conditions in steam, while producing H(2). Thermodynamic evaluation and process simulation of the CL-SMR reaction scheme using mixed iron-oxides was performed. Results indicate that FeMoO(4), Fe(2)ZnO(4) and Fe(2)MnO(4) generated syngas at 750 °C, 730 °C and 600 °C, respectively. However, FeMoO(4) was not fully regenerated under favorable conditions, whereas Fe(2)ZnO(4) and Fe(2)MnO(4) were completely regenerated at 440 °C and 640 °C, respectively. Fe(2)MnO(4) showed the most favorable operating conditions among the studied OC towards the production of syngas. Preliminary experimental studies involved the synthesis of Fe(2)MnO(4) through a solid-state method using Fe(2)O(3) and MnO as precursors, which was characterized via XRD, while its redox performance was evaluated in a TGA CH(4)–H(2)O redox cycle, with reduction using CH(4) followed by the steam oxidation of OC. Results indicate that both reduction with methane and oxidation with water vapor using Fe(2)MnO(4) present reasonable reduction–oxidation rates to be used in the CL-SMR reaction scheme, verifying the feasibility of the theoretical study performed in the present investigation.