Effect of Operating Parameters on Hydrothermal Liquefaction of Agricultural Waste

Abstract

The effect of operating parameters on hydrothermal liquefaction of rice hulls was studied within 200-300C at pressure of 5-25 MPa. Very trivial amount of gaseous products (mainly CO2) were detected. Carbon content in lignin-free solid residue was accounted to be 4.5-9.1 %, while the rest of carbon was liquefied. Five sugars which are beneficial for SCWG process were detected as the main components in the liquid products, with cellobiose as the highest portion. Temperature increase did not show clear correlation to carbon content in solid residue, while the increase of pressure gave smaller carbon residue amounts (i.e., larger extent of liquefaction). Finally, two-step liquefaction experiment gave an increase of TOC amount in liquid product compared with single-step liquefaction at 220C.