The shortcomings such as high water content, low energy density and difficulty to storage, have limited the large-scale applications of agricultural straw. The torrefaction characteristic of four typical straws in China such as rice straw, cotton stalks, corn stalks, wheat straw, was investigated, which was carried out in the fixed-bed reactor and focused on the evolution of physical and chemical properties of straw during torrefaction. After torrefaction, the apparent volume of agricultural straw was significantly reduced and a more uniform distribution of particle size was observed which suggested the grinding performance could be significantly improved. Meanwhile, the number of solid oxygen-containing functional groups in the solid product reduced. The significantly increasing of the fixed carbon content and the significantly decreasing of the oxygen content improved the heat value of solid products. Although the mass and energy production yield ratio decreased after torrefaction, the energy production yield ratio was better than the mass. The torrefaction was benefit to the improvement of energy property and material characteristics of straw and had a positive effect on the quality of biomass material.%农业秸秆由于含水量高、能量密度低、不易储存等缺点,限制了其规模化应用.以稻秆、棉秆等典型秸秆为研究对象,采用固定床反应器研究了秸秆的烘焙及其对秸秆物化特性的影响.结果表明:烘焙后农业秸秆表观体积明显缩小,粒度分布更加均一化,可磨性能得到显著提升；固体含氧官能团数量减少,同时固定碳含量显著提升,氧含量明显降低,发热量明显提高；然而烘焙后质量产率和能量产率均有所降低,但能量产率始终优于质量产率.烘焙有利于秸秆能源特性的提高和物化特性的改善,对提高生物质品质有积极的作用.
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