三维流化床内生物质及石英砂混合颗粒的流动特性

Flow characteristics of biomass particles and quartz sands in 3D fluidized bed

选择锯花、花生壳、稻壳、蔗渣为实验对象,将不同质量的生物质与石英砂混合作为床料,加入三维流化床试验台内混合流动,测量床内的压差脉动信号,床高1000mm,截面尺寸为120mm×32mm。实验结果表明当生物质质量分数小于等于2%时,生物质的种类及质量分数对最小流化速度的影响可以忽略不计。利用快速傅里叶变换变换分析压差脉动信号,研究双组分流动特征。结果表明,添加稻壳时压力脉动在低气速下主频位于10~15Hz区间内,并随着气速的增加向20~25Hz的高频区移动;蔗渣、花生壳及锯花等片状生物质在较低气速下主频消失,较高气速下主频存在于10~15Hz区间内。

Waste wood,peanut shells,rice husk,and pomace of sugarcane were chosen as experiment raw materials and mixed with quartz sands at different mass ratio to investigate the influence of biomass species and mass ratio in a 3D laboratory fluidized bed. The bed size is 1000 mm in height and 120mm×32mm of cross section horizontally. The pressure fluctuation inside the bed was recorded and analyzed. The results show that biomass species and mass ratio had negligible effect on minimum fluidization velocity when mass ratio was less than 0.02. Fast Fourier transform was employed to obtain the power spectral density of pressure fluctuation signals. It＇s shown that the PSD of pressure fluctuation at lower velocity ranged from 10 Hz to 15 Hz when rice husk was added,and increased to about 20 Hz to 25 Hz when the velocity increased. Pomace of sugarcane,peanut shells,and waste wood had no main frequency at lower velocity,but when the velocity increased the main frequency was found to be ranged from 10 Hz to 15Hz.