Characterization of products from hydrothermal liquefaction and carbonation of biomass model compounds and real biomass

The main properties of products from real biomass (water hyacinth, rice straw) and biomass model compounds (microcrystalline cellulose, xylan) by hydrothermal liquefaction (300°C for 30 min) and carbonation (220°C for 4 h) were examined in a batch reactor. The results showed that rice straw (RS) has the highest heavy oil yield of 21.62% from the hydrothermal liquefaction (HTL). The oil yields from HTL are 15.00%, 11.61%, and 12.19% for microcrystalline cellulose (MC), xylan (XL), and water hyacinth (WH), respectively. The yields and composition of the heavy oil depend on the chemical ingredients in real biomass. The major compounds of the liquid products from HTL were identified by TOC and GC-MS. The heavy oil mainly contains ketones, phenols, aldehydes, alcohols, and a few acids from different materials. The hydro-char, analyzed by SEM and TEM, is composed of carbon micro-spheres in the form of core-shell during HTC. MC, WH, and RS have higher char yield. Finally, the formation of carbon micro-spheres of the xylan was proposed.