In Situ Synergistic Catalysis Hydrothermal Liquefaction of Spirulina by CuO–CeO₂ and Ni–Co to Improve Bio-oil Production

Abstract

Hydrothermal liquefaction (HTL) is one of the most promising technologies for biofuel production. The preparation and application of catalysts for HTL have been the research focus in recent years. In this study, a new synergistic catalytic process strategy is proposed. CuO−CeO 2 /γ-Al 2 O 3 was used as an in situ hydrogen donor catalyst and Ni−Co/SAPO-34 was synthesized for hydroprocessing to improve bio-oil production process. The results of XRD and XPS demonstrated that the metal components were well supported on the catalyst. When the two catalysts were mixed, the yield of bio-oil increased from 51.00% to 64.51%, the carbon recovery rate raised from 69.53% to 88.18%, the energy recovery rate grew from 63.42% to 80.22%, and the S content is relatively reduced by 83.3%. Also, TG analysis showed that the content of light components in bio-oil increased. Moreover, the hydrocarbons and alcohols were observed to a higher proportion from the GC-MS analysis. This new method still has high catalytic activity after repeated use for five times. This study provides a new idea for preparing higher yield and superior quality bio-oil.

A Review of Hydrothermal Biomass Liquefaction: Operating Parameters, Reaction Mechanism, and Bio-Oil Yields and Compositions

“…Bio-oil produced by HTL contains large amounts of oxides, acids, phenols and other unstable compounds that need to be improved in terms of fuel properties through subsequent treatments. Strategies such as additive hydrogenation, deoxygenation and catalytic cracking can be used to modify characteristics such as viscosity, oxygen, nitrogen content, and chemical composition to meet fuel standards …”

Effect of Fe, Ni, and Co on the hydrothermal liquefaction of Chinese herb residue for bio-oil production

“…This trend is observed with Co/MCM-41, Fe-Ni/MCM-41, and Ni-Co/ MCM-41 supported catalysts. Additionally, the catalyst reduces the ester content in BO, potentially attributed to the catalyst's facilitation of acid or alcohol conversion into ketone and subsequent indirect inhibition of the esterification reaction [39]. The Fe-Co/MCM-41 catalyst shows the highest concentration of phenol, 2,6-dimethoxy, likely inducing ether bond cleavage or other ingredient conversion to phenol.…”