Abstract
Thermo-chemical conversion of wood biomass at low temperatures and aqueous conditions were performed using an autoclave. Hydrothermal treatment of wood biomass for the production of oxygenated hydrocarbons with various reaction conditions were carried out and optimized the reaction parameters for the high oil yields. Environmentally benign separation and analysis process applied for the identification of compounds at different stages to understand the nature of products. With low reaction temperatures, (180°C-250°C) high reaction times (60 min) are favored for high oil yields, and conversely at high reaction temperatures, low reaction times (15 min) favored. The use of base catalysts improved the conversion of biomass and subsequently high oil yields were observed. Under the optimized reaction temperature and time, the effect of various alkaline (Na and K) hydroxides and carbonates were investigated. In addition, the biomass components such as cellulose, lignin was also used for the hydrothermal treatment and compared the composition of oil products. Oil products were extracted from both liquid and solid portion of reaction products by different solvents and analyzed them individually. The use of alkaline hydroxides and carbonates had significant effect on products yield and composition of oil products. Catalytic hydrothermal treatment of biomass produced mainly phenolic compounds, benzenediol derivatives and the quantity of these compounds were changed depending on type of base solution. Compared to thermal run, the use of base solutions hindered the formation of char and favored the formation of oil. The volatility distribution of hydrocarbons were characterized by using C-NP gram ( C stands for carbon number and NP stands for normal paraffin) and it showed that the majority of hydrocarbons for all runs including thermal were distributed at the boiling point rage of n-C11 (174 to 198°C). The products from hydrothermal treatment of sawdust were analyzed using gas chromatograph equipped with mass selective detector (GC-MS), thermal conductivity detector (GC-TCD), 1H, 13C nuclear magnetic resonance (NMR), total organic carbon content (TOC) and ion chromatograph.
