Benzene, toluene and xylene (BTX) from in-situ gas phase hydrodeoxygenation of guaiacol with liquid hydrogen donor over bifunctional non-noble-metal zeolite catalysts

摘要

Hydrogen donors were employed to replace pure hydrogen as a hydrogen source for in-situ gas phase HDO due to their low storage and transportation cost. A series of catalysts have been prepared by modifying the zeolite HZSM-5 with polymetallic and multi-carriers. Gas-phase hydrodeoxygenation (HDO) of guaiacol was conducted under a pressure 2 MPa and a temperature at 350 degrees C. The effect of polymetallic and multi-carrier modification on HDO activity was investigated. The physicochemical properties of catalysts were characterized by BET, XRD, SEM, H-2-TPR, XPS and NH3-TPD. The characterization results showed that when La was loaded, the catalyst Ni/HZSM-5&La obtained a stronger medium-strong acidity. The electronic transfer of the elemental nickel was promoted. After HDO, the catalyst Ni/HZSM-5&La exhibited the highest HDO rate and BTX selectivity, reaching 97.79% and 34.25%, respectively. The real bio-oil HDO under a hydrogen donor were also analyzed. The results showed the content of the hydrocarbon compound were over 95%. The reaction mechanism was discussed through the distribution of liquid product species. Direct demethoxylation pathway (DMO) and methylation pathway (ME) were considered as the main pathways. (c) 2020 Elsevier Ltd. All rights reserved.