| 초록 |
Mixed hardwood chips were pre-extracted with green liquor prior to kraft pulping in order to recover hemicelluloses for use as biofuels. This green liquor solution containing mainly sodium sulfide and sodium carbonate was applied at different alkali charges of 0, 1, 3, and 5% on dry wood weight. The extractions were performed at 160 °C for residence times ranging from 1-2 h to determine the effect of extraction severity on composition of extract. The severity of extraction time and green liquor charge controls the concentration of acetic acid and monosaccharide sugars available for downstream processing, the accumulation of degradation products such as organic acids and furans in the extract. As the alkali charge was increased, the amount of acetate side chains on the hemicelluloses and the dissolved lignin in the extract increased but the carbohydrate and sugars in the extract decreased appreciably. |
