Abstract:
Hydrothermal liquefaction (HTL) and pyrolysis (Py) of Loktak lake biomass mixture of water hyacinth (WH) and para grass (PG) were carried out at 260–300 °C and 300–500 °C to compare the products yield and chemical characteristics of the products. In case of HTL, the maximum bio-oil yield was obtained 13.34 wt.% at 280 °C while for Py, the maximum bio-oil yield was observed 38.8 wt.% at 350 °C. The obtained bio-oils and bio-chars were analyzed using GC–MS, FT-IR, NMR, TGA, TOC, and SEM. GC–MS analysis of the bio-oils were showed that the HTL bio-oil majorly contains of nitrogen containing compounds whereas the Py bio-oil contains majority of phenolic compounds. Other compounds like ketones, alcohols, acids were also observed in bio-oil. Higher intensity broad band at 3300–3500 cm−1 was observed in the Py bio-oil compared to HTL bio-oil. TGA and proximate analysis of bio-char revealed the higher devolatilization occured during the HTL compared to Py process. The surface morphology of the HTL bio-char was found to be rough and fragmented as compared to the pyrolysis bio-char, clearly showing the biomass macromolecules breakdown differently in HTL and Py process.
