LaFe1-xNix as a Robust Catalytic Oxygen Carrier for Chemical Looping Conversion of Toluene

Chemical looping biomass gasification is a novel technology converting biomass into syngas, and the selection of oxygen carrier is key for efficient tar conversion. The performance of LaFe1-xNix as a robust catalytic oxygen carrier was investigated in the chemical looping conversion of toluene (tar model compound) into syngas in a fixed bed. LaM (M = Fe, Ni, Mn, Co, and Cu) was initially compared to evaluate the effect of transition metal on toluene conversion. LaFe (partial oxidation) and LaNi (catalytic pyrolysis) exhibited better performance in promoting syngas production than other oxygen carriers. Therefore, Ni-substituted ferrite LaFe1-xNix (x = 0, 0.2, 0.4, 0.6, 0.8 and 1) was further developed. The effects of Ni-substitution, steam/carbon ratio (S/C), and temperature on toluene conversion into C-1 and H-2 were evaluated. Results showed that the synergistic effect of Fe and Ni promoted toluene conversion, improving H-2 yield yet with serious carbon deposition. Steam addition promoted toluene steam reforming and carbon gasification. With S/C increasing from 0.8 to 2.0, the C-1 and H-2 yield increased from 73.9% to 97.5% and from 197.7% to 269.6%, respectively. The elevated temperature favored toluene conversion and C1 yield. LaFe0.6Ni0.4 exhibited strong reactivity stability during toluene conversion at S/C = 1.6 and 900 degrees C.

Automated summary

Chemical looping biomass gasification is a novel technology that converts biomass into syngas. In this study, LaFe1-xNix was investigated as a catalytic oxygen carrier for the conversion of toluene into syngas. The results showed that LaFe and LaNi exhibited better performance in promoting syngas production compared to other oxygen carriers. The addition of steam and the increase in steam/carbon ratio were found to promote toluene steam reforming and carbon gasification, leading to higher C-1 and H-2 yields. LaFe0.6Ni0.4 demonstrated a strong reactivity stability during toluene conversion.