Effect of cosolvent and addition of catalyst (HZSM-5) on hydrothermal liquefaction of macroalgae

The present study aimed to evaluate the effect of the direct liquefaction of macroalgae in an autoclave reactor (50 mL) possessing water and ethanol as cosolvent. The reaction conditions such as duration, temperature, algae/solvent ratio, the composition of cosolvent (ethanol-water) on product distribution, and bio-oil characterization were studied. The optimum conditions such as 300 degrees C of temperature, 45 minutes of reaction time, 75% of ethanol, and algae to solvent ratio of 4/40 g/mL supported the bio-oil yield of 46.75% with a conversion rate of 95.5%. The composition and concentration of the compounds in the bio-oil produced under various doses of catalyst were described using GC-MS. The bio-oil characterization showed that the esters were most predominant in hydrothermal liquefaction with a catalyst (HZSM-5) compared with hydrothermal liquefaction in the absence of the catalyst.