LAUSR

Abstract The co-hydrothermal liquefaction (HTL) of low-lipid microalgae (MA) mixed with starch-rich biomass waste (sweet potato residue, SPR) was performed. To explore the interaction effect at different mass ratios of MA/SPR, the distribution and composition of HTL products were analyzed. Results showed that although the addition of SPR did not obviously promote the formation of bio-crude by Maillard reaction between starch and protein, the generation of bio-char was boosted. On the other hand, the experimental higher heating values of both bio-crude and bio-char derived from co-liquefaction were greater than the theoretical calculated values. Meanwhile, the N content of bio-crude exhibited a declining tendency with higher dosage of SPR. For MA/SPR ratio of 3/1, the experimental energy recovery (70.8%) was greater than the theoretical calculated value (66.96%), suggesting the synergistic effect on reaction efficiency. Furthermore, GC/MS analysis of bio-crude showed a lower relative percentage of alkylamides but higher hydrocarbons with MA/SPR ratios ranging from 5/1 to 3/1, indicating the positive interaction effect between MA and SPR.