In Situ Hydrodeoxygenation of Phenol as a Model Compound for Pyrolysis Oil Using Raney Ni and Molecular Sieve Catalysts

Abstract

In order to reduce the consumption of a large amount of externally supplied hydrogen, methanol was used as the hydrogen donor solvent. Phenol, a model compound of coconut clothes pyrolysis oil, was in situ-hydrodeoxygenated using low-cost Raney Ni plus SAPO-11 or Zr-SBA-15 molecular sieve catalysts by tandem reactions. As a result, different n(Si)/n(Al) of SAPO-11 had less influence on the conversion of phenol and a greater influence on the selectivity of the product. However, different n(Si)/n(Zr) of Zr-SBA-15 had little effect on the conversion of phenol and the selectivity of products. The optimal catalyst SAPO-11 (n(Si)/n(Al) = 0.3) was selected to investigate the hydrodeoxygenation (HDO) of phenol by the single factor conditions and then the reaction conditions were optimized by response surface methodology. The results showed that the conversion of phenol was 97.48%, and the selectivity of cyclohexane was 10.2%. The catalyst can still provide satisfactory results after four runs, and the conversion of phenol can still reach 78.65%. Under the optimal process conditions, HDO research was conducted on crude biomass pyrolysis oil. The results showed that the phenol content in the upgraded bio-oil was greatly reduced, the hydrocarbon content was 9.97%, and the higher heating value was from 24.61 to 30.65 MJ/kg, which indicates that the mixed catalyst also has a good effect on the in situ HDO of coconut clothes pyrolysis oil.