Fluidized and vibrofluidized shallow beds of fresh leaves

来源 :颗粒学报(英文版) | 被引量 : 0次 | 上传用户:wjlwny110
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
The fluid dynamics behavior of shallow fluidized and vibrofluidized beds operating with fresh leaves was investigated with the aim of exploring drying applications in a modified conveyor belt (MCB) system, which may be operated in a fixed- or fiuidized-bed mode. Leaves of the specimens Duranta repens,Schinus molle, Coleus barbatus, Buxus sempervirens, and Bougainvillea spectabilis were tested with a range of sphericities from 0.063 to 0.213. bulk densities from 0.038 to 0.251 g/cm3. apparent densities from 0.52 to 0.97 g/cm3 and ratios of total surface area to volume from 21 to 224 cm-t. Fluidization characteristic curves were obtained by measuring pressure drops versus air velocity in a rectangular column of 0.20m x 0.11 m cross section. It was not possible to reach real fluidized regimes with the leaves due to strongly non-homogeneous beds. Nevertheless, the characteristic curves allowed for the identification of a transition regime from fixed- to expanded-beds, and parameters such as air velocity and pressure drop obtained from the experimental data at the transition were reproducible for specimens with lower surface area or lower specific gravity (i.e., Duranta repens, Schinus molle, and Bougainvillea spectabilis).The transition velocity and pressure drop could not be predicted by the literature developed for estimat0.5 and 1.0 helped to reduce channeling and decrease the transition velocities from fixed to expanded regimes although it did not affect the pressure drops after the bed expansion. The results suggest that drying fresh leaves using the MCB dryer operating in a fluidized mode would not be feasible because none of the materials investigated attained a high-quality fluidization. Operation of the MCB dryer may be possible by alternating between the fixed and vibrofluidized modes. For the specimens tested, the drying should be performed in a range of air velocities from 0.50 to 0.60 m/s to ensure that the operation is in a vibrofluidized regime. The choice of an adequate vibration parameter will depend on the leaf characterisdifferences on the fluid dynamics behavior of vibrofluidized beds for the conditions investigated.
其他文献
Gateways at faces of great mining heights are mostly driven along the roof of coal seams. For gateway height restrictions, a 1-3 m floor coal is retained, leavi
文章阐述了建筑节能发展的历史丛然性,并从绿色建筑和可持续发展、环境空气保护的制约关系说明建筑节能的必然性.
A novel coordination polymer of Cun with flexible ligands,namely,[Cu3(mal)2(di-2-pyridlyktone)2] (1,H2mal = maleie acid),was synthesized and characterized by si
In wireless ad hoc networks cooperation among nodes cannot always be assumed since nodes with limited resources and different owners are capable of making indep
Given the difficulties encountered in roadway support under coal pillars, we studied the characteristics of stress distribution and their effect on roadway stab
二恶英是广泛分布于环境中的一类重要的有机污染物.本文利用分子碎片法对51种二恶英类物质的正辛醇/水分配系数进行了估算,并与实验值进行了对比.在此基础上又对二恶英的性质
The toxicity of naphthalene to a freshwater microalga, Chlorella pyrenoidosa, and the subsequent recovery of algae from the damage were investigated under two n
高校会计委派制度已成为目前高校推广的一种财务监督模式。本文旨在通过分析高校会计委派制度的由来及其实质,重点探讨高校会计委派制度的积极意义和客观弊端。 College acc
本文梳理了宜兴市环保产业的发展过程,探讨了其技术发展模式和集群模式特征,并在此基础上提出了相关发展建议.
随着土地出租和土地市场的启动,不同的利益集团参与到城市建设过程中,城市土地开发已成为一种市场行为,其中对某-工业规划用地进行了剖析,并且利用地理信息系统的空间分析功