Effects of temperature, reaction time, atmosphere, and catalyst on hydrothermal liquefaction of Chlorella

Abstract

Hydrothermal liquefaction (HTL) is the direct conversion of wet biomass into bio‐oil at high temperature (200–400°C) and high pressure (10–25 MPa). In this work, we investigated HTL with 4.5 g of Chlorella and 45 ml of water/ethanol (1:1 vol. ratio) in a 100 ml reactor. Bio‐oils produced are characterized via elemental analysis, thermogravimetric analysis, and gas chromatography–mass spectrometry (GC–MS). HTL of Chlorella was investigated at 240 and 250°C for 0 and 15 min under an air or H2 atmosphere and with and without 5% zeolite Y. Temperature increased the bio‐oil yield from 38.75% at 240°C to 43.04% at 250°C for 15 min reaction time. Longer reaction time increased the bio‐oil yield at 250°C from 39.14% for 0 min to 43.04% for 15 min. The H2 atmosphere had a significant effect for HTL at 240°C. Zeolite Y increased the bio‐oil yield significantly from 32.03% to 43.06% at 250°C for 0 min. The carbon content of bio‐oil increased with the temperature while the oxygen content decreased. The boiling point distribution of bio‐oils in the range of 110–300°C varies with temperature, and atmosphere. At 240°C for 15 min, the 110–300°C range increased from 31.19% in air (240‐15‐air) to 39.25% in H2 (240‐15‐H2). The H2 atmosphere increased the content of hydrocarbons, alcohols, and esters from 69.61% in air (240‐0‐air) to 82.83% in H2 (240‐0‐H2). Overall, temperature, reaction time, atmosphere, and catalyst all significantly influenced the yield and/or quality of bio‐oils from HTL of Chlorella.

Co-liquefaction of α-cellulose and phycocyanin: A preliminary study

“…However, after further increasing to 320 °C, the final reaction pressure reached 14 MPa, and the oil yield decreased. This phenomenon is similar to the co-liquefaction of real biomass (Anamul Haque et al 2023), indicating that using the model compound would be representative in terms of bio-oil yield and reaction to some extent.…”

A review on thermochemical based biorefinery catalyst development progress

“…Zeolites are cheap, have a high surface area, can be modified easily and are active for cracking and deoxygenation reactions. 36,344 Therefore, they have been used in the HTL process. 36 In Table 13, 230,330,345–350 the results of the use of different zeolites during the HTL process of biomass are shown.…”