稻壳粉燃烧过程中颗粒尺寸和形态的演变

以颗粒尺寸为250 ~ 300 μm的稻壳粉为研究对象,通过高温沉降炉中的热解和燃烧实验结合颗粒样品的扫描电子显微镜图像分析方法,研究了稻壳粉燃烧过程中颗粒尺寸和形态的变化及热解、燃烧条件的影响。结果表明,热解时颗粒宽度等尺寸参数均缩小,温度的影响较小;焦燃烧时颗粒尺寸因破碎明显减小,温度、气氛等燃烧条件通过影响破碎进而影响尺寸变化。对于形态参数,热解和燃烧后横纵比的变化及实验条件对其变化的影响与尺寸参数相似;热解和燃烧后圆形度几乎无变化;圆度在热解后变化也较小,而燃烧后明显减小;实验条件对圆形度、圆度的变化几乎无影响。

Evolution of Particle Size and Morphology during Pulverized Rice Husk Combustion

Size and morphology evolutions during combustion of pulverized rice husk of 250-300 μm and the influence of devolatilization and combustion conditions were studied by means of devolatilization and combustion experiments in a high-temperature drop tube furnace combined with scanning electron microscope image analysis on particle samples. Results showed that the particle size decreased and the influence of temperature was small during devolatilization; while the size of char particles decreased obviously due to the fragmentation during combustion and the combustion conditions such as temperature and atmosphere, affected the size changes by influencing the fragmentation. For morphology, the change of aspect ratio and the influence of experimental conditions were the same as those for the size parameters. Circularity showed little change during devolatilization and combustion. Roundness changed little after devolatilization while it decreased obviously after combustion, and the experimental conditions had little impact on circularity and roundness changes.