Ex-situ catalytic upgrading of pyrolysis vapors using mixed metal oxides

Ex-situ catalytic fast pyrolysis (CFP) was employed to produce bio-oils from beech wood. The effect of Nb-based mixed oxides (with second metal oxide = W, Al or Mn) in upgrading the vapors compared an H-ZSM-5 catalyst and non-catalyzed pyrolysis. catalysts acidic properties were assessed by NH3-TPD FTIR adsorbed pyridine. obtained characterized Karl-Fischer titration, GPC, CHNS analyses, 13C-NMR, GC–MS, GCxGC–MS. In spite their very different properties, NbxMnyOz essentially Lewis acid sites) exhibited similar performances as (that presents a high density Brønsted sites), terms liquid phase selectivity reduction oxygen content produced. These observations accompanied compounds such acids, aldehydes, ketones, ethers sugars that contribute detrimental bio-oils. Finally, results suggest sites are converted into presence water vapor produced wood, whereas strongest have limited impact on process due accessibility for most components vapors.