报告题目：Ternary Phase Diagram of Pyrolytic Lignin, Mixed Solvent, and Water: Understanding and Controlling Bio-oil Phase Stability
报 告 人：Prof. Hongwei Wu，Curtin University, Australia；Associated Editor of Energy & Fuels
Professor Hongwei Wu is the head of Discipline of Chemical Engineering, Western Australian School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, Australia. At Curtin, Prof. Wu leads a sizable research group dedicated to fundamental studies into thermochemical processing of various fuels, particularly coal, biomass and solid wastes. In recent years, Prof. Wu has been focusing on fundamental R&D on production, characterization and applications of biomass-derived fuels (e.g. bio-oil, biochar, bioslurry) in the context of future sustainable development. Since 2018, Prof. Wu has been serving as the Associated Editor of Energy & Fuels – a journal published by the American Chemical Society (ACS). Recently, Prof. Wu has also received the inaugural 2018 Curtin Awards for Excellence in Higher Degree by Research Supervision.
Fast pyrolysis bio-oil generally contains a water-soluble fraction (excluding water), a water-insoluble fraction (i.e., pyrolytic lignin, PL), and water in a single phase. However, phase separation can occur during bio-oil transport, storage, and processing. This talk discusses the development of a mixed solvent (MS) based on the compositions of various fast pyrolysis bio-oils produced from a wide range of feedstocks and reactor systems. The phase behavior of the PL/MS/water ternary system is then reported and ternary phase diagrams are constructed for the ternary systems of PL (or its fraction), MS and water. It is found that the phase stability of the PL/MS/water system is strongly determined by the composition of the system. For example, the PL/MS/water system is always stable when the MS content is >50 wt %, while the system is always phase-separated when the PL content is >54 wt %. A comparison of the results for various PL fractions indicates that the molecular weight of PL can affect the ternary phase diagram, with the PL of a lower molecular weight having a higher solubility in the same MS/water mixture. The presence of free sugar (i.e., levoglucosan, present in bio-oil as solute) also influences the ternary phase diagram of the PL/MS/system, but only at a low water content (i.e., < 20 wt %). The results suggest that such ternary diagrams may be potentially an important tool for predicting the phase separation of bio-oil, as a result of changes in the bio-oil chemistry in various processes (e.g., cold-water precipitation and aging).