Abstract: The inclusion of additives in the biomass pelletizing process is an effective method to improve the pellet quality, which affects the mechanical behavior of the biomass in the densification process significantly. Based on the thickwalled cylinder principle, a mechanical behavior testing system for the biomass densification process was established, and the effects of waste oil additives on the mechanical behavior of the wheat straw and rice straw molding process were studied. The results showed that the peak stress ratios of wheat straw and rice straw ranged from 0.73 to 0.96 and 0.51 to 0.69, respectively. The final stress ratios ranged from 0.46 to 0.68 and 0.38 to 0.55, respectively. The waste oil additive can change the radial stress ratio of materials in the pressing process, but the extent of their influence varies for different materials. With the increase of additive content, the proportion of radial stress increases, but the mechanical properties and its variation trend are anisotropic. There is no definite mapping relationship between stress ratio and product density, and therefore, the product density cannot be determined directly from the mechanical behavior in the molding process.

Key words: crop straw, biomass pellets, mechanical behavior, oil additives

摘要： 在生物质致密成型过程中加入添加剂是改善成型条件、提高制品品质的有效手段，对成型过程力学行为有直接影响。基于厚壁圆筒原理构建生物质致密成型过程力学行为测试系统，以小麦秸秆和水稻秸秆为对象，研究废机油添加剂对成型过程力学行为的影响。结果表明：小麦秸秆和水稻秸秆对应峰值应力比值范围分别为0.73~0.96和0.51~0.69；对应的终值应力比值范围分别为0.46~0.68和0.38~0.55；废机油添加剂会改变压制过程中物料径向应力占比，但对不同材料的影响程度不同；添加剂含量增加使径向应力占比总体变化趋势为递增，但力学性能及其变化趋势呈各向异性。应力占比与制品密度没有确定的映射关系，不能直接通过成型过程中的力学行为判断制品密度。

关键词: 秸秆, 生物质成型燃料, 力学行为, 油性添加剂