Catalytic hydrothermal liquefaction of microalgae over different biochars

Abstract

Herein, four kinds of low-cost biochars (i.e. straw, rice husk, peanut shell and sawdust biochar) were used as the catalysts and their influence on the HTL of microalgae was investigated. It indicated that the biochars could improve the bio-oil quality. Particularly, the sawdust biochar increased the higher heating value of the bio-oil from 35.8 MJ/kg (without biochar) to 37.7 MJ/kg. The straw biochar increased the low boiling fraction (< 200 °C) of bio-oil by about 15% compared with that of the bio-oil without catalysts. Overall, the biochar is beneficial for the bio-oil used as transportation fuels in the future.