Effect of Li-LSX-zeolite on the in-situ catalytic deoxygenation and denitrogenation of Isochrysis sp. microalgae pyrolysis vapours

• Published in: Fuel processing technology 2018-05, Vol.173, p.253-261
• Main Authors: Rahman, Nur Adilah Abd, Fermoso, Javier, Sanna, Aimaro
• Format: Article
• Language: English
• Subjects: Algae; Alkenes; Ammonia; Aromatics; Bio-oil; Biomass; Catalysis; Catalysts; Catalytic pyrolysis; Coke oven gas; Costs; Denitrogenation; Deoxygenation; Gasoline; Li-LSX-zeolite; Microalgae; Natural gas; Pyrolysis; Zeolite; Zeolites
• ISSN: 0378-3820; 1873-7188
• DOI: 10.1016/j.fuproc.2018.01.020

In this work, we report for the first time the use of Li-LSX-zeolite as catalyst for the catalytic pyrolysis of biomass (Isochrysis sp. Microalgae). Li-LSX-zeolite showed a good catalytic performance, principally for bio-oil denitrogenation (mainly in form of NH3), and good activity for olefins and aromatics production. At 500 °C, 11.8% aromatics and 23.1% aliphatics were produced. The increase of temperature led to transfer of C to the gas phase, coke formation on the catalyst surface and decrease in N-compounds in the bio-oil. The increase of the catalyst to biomass ratio from 0 to 3:1 resulted in the aromatics being five-fold those non-catalytically obtained and in a higher cracking power that reduced the bio-oil to 23% at expenses of olefins rich gas. However, a linear correlation between coke formation and aromatic yield was observed as the catalyst to microalgae ratio was increased. Therefore, the experimental results indicate that Li-LSX-zeolite could be used as catalyst for in-situ denitrogenation of microalgae bio-oil and for enhancing aliphatics and aromatics formation to be blend in gasoline and diesel and olefins in gas phase. •For the first time Li-LSX-zeolite has been evaluated as catalyst for microalgae pyrolysis.•Li-LSX-zeolite (3:1 cat:bio ratio) reduced N content in bio-oil from 3.9 wt% (non-catalytic) to 0.8 wt% at 500 °C.•Acid properties of Li-LSX-zeolite promoted cracking and aromatization reactions.•Li-LSX-zeolite produced 45% diesel compound at 500 °C, which were converted to gasoline (27%) and olefins at 700 °C.•Coke formation and aromatic yield were linearly correlated.