Hydrothermal liquefaction of macroalgae: Influence of zeolites based catalyst on products

Abstract Hydrothermal liquefaction (HTL) of Ulva prolifera macroalgae (UP) was carried out in the presence of three zeolites based catalysts (ZSM-5, Y-Zeolite and Mordenite) with the different weight percentage (10-20 wt.%) at 260-300 °C for 15-45 min. A comparison between non-catalytic and catalytic behavior of ZSM-5, Y-Zeolite, and Mordenite in the conversion of Ulva prolifera showed that is affected by properties of zeolites. Maximum bio-oil yield for non-catalytic liquefaction was 16.6 wt.% at 280 °C for 15 min. The bio-oil yield increased to 29.3 wt.% with ZSM-5 catalyst (15.0 wt.%) at 280 °C. The chemical components and functional groups present in the bio-oils are identified by GC-MS, FT-IR, 1 H-NMR, and elemental analysis techniques. Higher heating value (HHV) of bio-oil (32.2-34.8 MJ/kg) obtained when catalyst was used compared to the non-catalytic reaction (21.2 MJ/kg). The higher de-oxygenation occurred in the case of ZSM-5 catalytic liquefaction reaction compared to the other catalyst such as Y-zeolite and mordenite. The maximum percentage of the aromatic proton was observed in bio-oil of ZSM-5 (29.7%) catalyzed reaction and minimum (1.4%) was observed in the non-catalyst reaction bio-oil. The use of zeolites catalyst during the liquefaction, the oxygen content in the bio-oil reduced to 17.7%. Aqueous phase analysis exposed that presence of valuables nutrients.