【作者】 曹长青； 刘明言； 王一平； 秦秀云； 胡宗定；

【Author】 CAO Chang-qing LIU Ming-yan WANG Yi-ping QIN Xiu-yun HU Zong-ding (School of Chemicl Engineering & Technology, Tianjin University, Tianjin 300072, China)

【机构】 天津大学化工学院；

【摘要】 应用开发的微电导探针测试技术,对聚乙烯颗粒(dp4.01 mm,ρs=926 kg.m-3)为固相,水、0.05%(ω)SCMC(羧甲基纤维素钠)及0.2%(ω)SCMC水溶液为液相,空气为气相的逆流三相湍动床(ITPTB)的各相局部含率进行了同时测定,获得了540套局部相含率实验数据.在表观气速ug等于Ug3(颗粒在轴向均匀分布时的表观气速)时,通过对局部固含率(ωs)和局部气含率(ωg)的径向分布实验研究发现:εs呈现床中心处小,床壁处大的分布规律,且在r/R=0.75-0.90范围内有一个极大值峰,极大值峰在径向出现的范围与传统流化床相比增大:εg呈现床中心处最大,床壁处最小的分布规律,与传统流化床相比εg在径向上的非均匀性分布愈加明显.另外,根据εs的轴向分布特性,确定了ITFFB的不同操作流型,得到了相应流型下三个特征表观气速Ug1、Ug2和Ug3.实验考察了液体的粘度(μl)、颗粒静止高度与颗粒和液体总静止高度之比(Hs0/H0)及液体静止高度(H10)对三个特征表观气速Ug1、Ug2和Ug3的影响规律.更多还原

【Abstract】 Local phase holdups in an inverse three-phase turbulent bed of 150mm i.d. and 4350 mm height are measured simultaneously by micro-electrical conductivity probe technique in this paper. The experiments are carried out with polyethylene particles (dp=4.01 mm, ps=926 kg.m-3), with air, and with water, 0.05%(ω)SCMC and 0.20%(ω)SCMC as solid phase, gas phase and liquid phase respectively. Solid particles are fluidized by only an upward gas flow. 540 sets of experimental data of local phase holdups in radial direction are obtained under ug=ug3. It is found that the distribution of local solid holdup has a maximum peak at r/R=0.75-0.90. The range of appearing maximum peak is larger than that of conventional fluidized beds. The distribution of local solid holdup in radial direction has a minimum value at the column center and a maximum value at the column wall. However, the distribution of local gas holdup is just reverse to conventional fluidized beds. Otherwise, the operation regimes are obtained and characterized by the distribution of local gas holdup in radial directions,which is more significantly than that of some specific gas velocities (Ug1,Ug2 and Ug3) on the basis of the axial distribution characteristics of cross-sectional average solid holdups. The effects of the operating conditions (liquid viscosity, initial volume fraction of solids Hs0/Ho, initial liquid height H10) on the specific gas velocities are presented.更多还原