CHARACTERIZATION OF LIQUID PRODUCT FOR THE FEASIBILITY ANALYSIS OF PHENOLIC SUBSTANCE RECOVERY FROM PYROLYSIS PROCESS OF WOOD BIOMASS

摘要

Environmental issues related with organic waste disposal have been more important than before and there are several efforts to convert these wastes into eco-friendly products along with some intentions of material utilization and energy recovery. Lignin, a polyphenolic component, is one of potential renewable raw materials as a substitute for phenols produced from petroleum. Industrial applications of lignin as a chemical feedstock have, however, been seriously limited for its low reactivity. Fast pyrolysis technique was attempted to obtain a suitable lignin material as a substitute for phenol, using a fluidized-bed reactor at the condition of 300～500°C. Kraft lignin(KL) and milled wood lignin(MWL) were also separated as comparative materials from same kind of wood, Pinus radiata D. Don, which pyrolytic lignin(PL) is produced from. Because the quality of lignin for industrial application could be determined by the guidelines based on physico-chemical characteristics, the average molecular weights of lignin samples were determined using gel permeation chromatography(GPC), while phenolic hydroxyl groups were analyzed with gas chromatography, and 13 C-NMR spectra were also applied to observe their structural features. Depending on GPC analysis, PL has lower average molecular weight(MW), about 1200 g mol -1 , compared with those of KL and MWL, about 5400 and 7600 g mol -1 , respectively. The polydispersity of PL was also smaller than those of KL and MWL. The concentration of phenolic hydroxyl groups of PL was lower than that of KL, but similar with that of MWL. Comparing with the 13 C-NMR spectrum of MWL, the signal assigned to methoxyl groups was a little weakened in the KL spectrum, but this is even more reduced in the pyrolytic lignin product spectrum. According to the experimental results, PL is considered a homogeneous polymer having lower molecular weight and less methoxyl groups than KL with no substantial decrease of phenolic hydroxyl group, indicating that there is a possibility of recovering phenolic substances from wood biomass or wood waste through fast pyrolysis process.