关键词: 生物质, 湿式烘焙, 能量密度, 燃料, 热化学

Abstract:

Wet torrefaction (WT), as a biomass pretreatment technology in superheated water at temperatures within 180—260℃, has received extensive attention because of its high adaptation, low energy consumption, superior pretreatment effect and other advantages. But it remains some disadvantages because WT is still in its infancy. In this paper, the definition, reaction mechanism and advantages of WT are reviewed, and the improvement in physical and chemical properties of WT solid products is highlighted (under the optimal conditions, the product mass density, energy density, pellet durability, calorific value and ignition temperature increased by 33.2%, 48.2%, 33.0%, 45.1% and 67℃, respectively, while the grinding energy consumption and equilibrium moisture content decreased by 25.6 times and 2.9 times, respectively). The impacts of WT conditions on the treatment performance are discussed, and the internal relationship between WT conditions and fuel property is determined. Particularly, the research progress of WT and its subsequent applications are comprehensively overviewed, and the economic feasibility of WT is generally analyzed. Finally, the shortcomings of WT and the remediation are clarified. At the same time, it is hoped to provide some analyses and outlooks for future application scenarios of WT, so that WT will have better environmental friendliness and economic feasibility.

Key words: biomass, wet torrefaction, energy density, fuel, thermochemistry