Syngas Production by Fe2SiO4 Oxygen Carrier in Chemical Looping Partial Oxidation of Methane

Chemical looping partial oxidation of methane (CLPOM) is a low energy consumption and environmentally friendly new technology that can generate syngas. The main challenge is to find suitable oxygen carriers, which should be highly active, stable, low cost, and eco-friendly. This study found that Fe2SiO4 had good reactivity in the CLPOM process. Thermodynamic calculations were carried out by FactSage8.1 to demonstrate the feasibility of Fe2SiO4 as an oxygen carrier for CLPOM. Fe2SiO4 was prepared by the direct ball milling method and the high-temperature solid-phase synthesis method. The reaction properties of Fe2SiO4 were investigated in the fixed bed reactor. The XRD and FTIR results indicate that Fe2SiO4 can be synthesized successfully through the high-temperature solid-phase synthesis method. The results of fixed bed experiments showed that when the reaction temperature was 980 °C and the reaction time was 28 min, the XCH4 reached 87%, and the SH2 and SCO were 70% and 71%, respectively. Subsequently, 20 redox cycle experiments were conducted under the optimal reaction conditions. The results showed that Fe2SiO4 exhibited good reactivity in the first two cycles, and as the reaction progressed, the reduced oxygen carrier could not regain the lattice oxygen, leading to a decline in cyclic performance. This study demonstrates that Fe2SiO4 can couple CO2 and CH4 to produce syngas and is conducive to reducing carbon emissions.