Torrefaction Enhanced Biomass Chemical-Looping Gasification Coupled with Co2-Splitting Via Half Doped Lafe0.5m0.5o3 Perovskites

Half doped LaFe0.5M0.5O3(M=Mn, Co, Ni, Cu) perovskite was employed as oxygen carriers/gasification agents in the gasification of torrefied biomass (TB) coupled with CO2 splitting, The effect of torrefaction temperature on the syngas yield and CO formation rate as well as the M doping half doped perovskites were evaluated via thermogravimetric analyzer and fixed-bed reactor. Moreover, the oxygen transfer properties of doping-LaFe perovskites, the composition and surface topography evolution during coupled gasification were studied. The results showed that the M-doped perovskite exhibited higher activity in the gasification process, which promoted the conversion of TB and the yield of H2 and CO. Especially, CO and H2 yield decreased gradually with the torrefaction temperature, and the H2/CO ratio increased to 2.0 at the torrefaction temperature of 320 ℃. Moreover, LaFe0.5Ni0.5O3 exhibited better performance in both the gasification and the CO2 splitting reaction, and the yield of H2 and CO reached 3.71 mmol·g-1 and 1.80 mmol·g-1, respectively. Furthermore, the composition and surface topography evolution of doped perovskite were analyzed via SEM and XRD, while EPR and XPS to reveal the reaction mechanism. Moreover, after gasification, reduced doped perovskite provided metal and alloy sites and enhanced system basicity property promoting CO2 absorption and activation