Thermal and thermocatalytic degradation of Desmodesmus SP. microalgae with HBeta 38

•Explore sustainable energy from microalgae thermal conversion using HBeta 38 zeolites.•Zeolite HBeta 38structure confirmed and active in pyrolysis process.•With HBeta 38, bio-oil reduced oxygenated compounds by 69% (dry) and 52% (acetylated).•HBeta 38 enhanced aromatic compounds by 59%, hinting aviation biokerosene potential. This study investigates the thermal and thermocatalytic conversion of Desmodesmus sp. microalgae using microporous zeolite HBeta 38 as a catalyst to obtain a greater amount of renewable hydrocarbons. In this context, the pretreatment (acetylation) of biomass was also evaluated. The characterization of the catalyst confirmed its microporous structure, ar reported inliterature. The microalgae biomass, analyzed through thermal and thermocatalytic studies, revealed three distinct degradation events, with the catalyst influencing the degradation process. Reaction kinetics were assessed using the Ozawa-Flynn-Wall (OFW) and Kissinger-Akahira-Sunose (KAS) methods at various heating rates, demonstrating reliability with R2 values exceeding 0.9. In the absence of HBeta 38, the apparent activation energy for 50 % biomass conversion was 173 kJ mol−1 (OFW) and 172 kJ mol-1 (KAS), while the mixture with 12 % HBeta 38 had 188 kJ mol−1 (OFW) and 187 kJ mol−1 (KAS). Thermocatalytic pyrolysis, analyzed by gas chromatography coupled to a mass spectrometer (GC/MS), demonstrated that HBeta 38 reduced oxygenated compounds by 69 % for dry biomass and 52 % for acetylated biomass. Conversely, it promoted the formation of aromatic compounds, contributing to a 19.05 % and 59.31 % increase in dry biomass and acetylated biomass, respectively, supporting the production of Sustainable aviation fuel (SAF).