共查询到15条相似文献,搜索用时 62 毫秒
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为了解决水平液固循环流化床中颗粒分布不均匀问题,在内径29 mm、长4 m的水平有机玻璃管流化床内放入Kenics静态混合器,采用CCD图像测量与数据处理系统考察静态混合器的结构、个数、安装位置对液固二相流中颗粒分布的影响;同时,利用U型管压差计考察不同条件下静态混合器的压降。实验结果表明:Kenics静态混合器能明显地改善管内颗粒分布情况;单个扭率Y=3.5的Kenics静态混合器压降最小;2个扭率Y=3.5的Kenics静态混合器间距为40 mm时对颗粒分布影响长度是最长的。 相似文献
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液-固流化床中液速分布与颗粒循环流动 总被引:4,自引:0,他引:4
通过理论分析和实验研究考察了液一固平板流化床中颗粒流和液流的运动规律,提出了将分散的颗粒流连续介质化的假设和基于容积通量的流休力学表达方式,建立了液体流动和颗粒循环流动的数学模型并定义了颗粒流与液流的有效粘度。理论计算表明,液体通量的径向分布为抛物线,液流有效粘度和液含率与表观液速有关:颗粒通量的径向分布也为抛物线且颗粒上流区与回流区的分界点在0.577D,循环流动强度取决于液含率和液体密度,但颗粒循环分界点的位置与颗粒类型和操作液速无关。实验观察支持模型预测结果。 相似文献
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对水平多管液固流化床颗粒分布进行了实验研究,采用CCD图像采集系统,获得了颗粒的分布状况。研究表明,颗粒直径与密度的大小影响着颗粒的均匀分布。 相似文献
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在二维中试循环流化床中使用组合式固液分布器进行实验,考察下管箱表观液速,主分布器内径、主分布器下插深度,颗粒加入量和粒径对径向管束固含率的影响.结果表明:固含率随主分布器内径、颗粒加入量和下管箱表观液速的增加而增大,随粒径的增大而减小,随主分布器下插深度几乎没有变化;固含率不均匀度随颗粒粒径的增大而增大,随下管箱表观液速、颗粒加入量,主分布器下插深度增加而减小,但达到一定深度后,不均匀度不再随之减小,随主分布器内径几乎没有变化.在综合考虑各影响因素的基础上,提出计算固含率的经验公式,并用实验数据拟合了公式中的参数. 相似文献
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液固流化床中颗粒循环运动机理的初步研究 总被引:4,自引:0,他引:4
液固流化床中颗粒循环运动机理的初步研究胡新辉朱家骅夏素兰石炎福(四川联合大学化学工程系,成都610065)关键词:液固流化床颗粒运动径向液速分布1引言随着流态化技术在生物化工与能源等领域的不断推广应用,对液固流化床需要更深入的研究。以前的研究认为在... 相似文献
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在高18 m、内径80 mm的循环流化床提升管内分别考察了三种入口结构对颗粒流动特性的影响。实验结果表明:入口结构主要影响提升管底部区域的颗粒流动特性,不同入口结构对颗粒流动影响不同。相同操作条件下,当采用多管式入口结构时,径向上提升管底部区域的颗粒浓度分布相对均匀,轴向上颗粒能够迅速达到充分发展状态,充分发展高度在9 m左右;当采用多孔板入口结构时,径向上提升管底部颗粒浓度差别较大,轴向上颗粒发展较慢,需要更高高度才能达到充分发展,充分发展高度约为11 m;当采用单管式入口结构时,径向上颗粒浓度分布和轴向上颗粒充分发展速度均处于前两者之间,底部颗粒浓度径向分布仍为中间稀、边壁浓的不均匀分布,颗粒浓度轴向充分发展高度约为10 m。 相似文献
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循环流化床多联供试验台调节特性的试验研究 总被引:1,自引:1,他引:0
在一个循环流化床与移动床结合的多联供冷态试验台上,循环床与移动床之间用改进的气动分配阀控制循环物料的分配,提升管直径为400mm、高度为6000mm,移动床直径为476mm、高度为1200mm。进行了单回路运行和双回路同时运行的试验,对气动分配阀返料特性和系统压力分布进行了研究。在气动分配阀的返料临界压力范围内,在两侧存在压差的情况下,气动分配阀可以实现对循环物料在回路1和回路2之间分配的调节控制。试验结果为循环流化床多联供热态试验台的设计提供了一些经验。 相似文献
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The influence of distributor structure on solids distribution is studied in two riser circulating fluidized bed reactors with different distributor structures but similar diameters. Optic fibre probes were used for the measurement of local solids distribution. The axial and radial distribution of solids holdup in the riser with a multi‐tube distributor is more uniform than that with a multi‐orifice distributor. The radial profiles of particle velocity in the riser with the multi‐tube distributor are also more uniform than that with the multi‐orifice distributor. In the riser with the multi‐tube distributor, both gas and particles are distributed more uniformly across the section, so that the flow acceleration is much more uniform and faster. The flow development is much faster and the fully developed region is reached early for the riser with the multi‐tube distributor. The distributor design is an important factor for the design of circulating fluidized bed reactor. 相似文献
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S.A. Razzak 《Powder Technology》2010,199(1):77-5662
Axial distribution of phase holdups was studied in the riser of a gas-liquid-solid circulating fluidized bed (GLSCFB). The effects of gas and liquid superficial velocities as well as solids circulation rate on radial distribution of phase holdups at different axial locations were investigated. Electrical resistance tomography (ERT) and optical fiber probe were employed online in the experiments for a precise determination of phase holdups. An empirical model was developed for the determination of gas bubbles in analysis of data obtained by fiber optic sensor. Gas holdup was higher at the central region of the riser and increased axially due to coalescence of small bubbles and decrease of hydrostatic pressure at higher levels in the riser. This led to an increase in solids holdup in regions close to the wall which was slightly higher than the solids holdup at the wall. Both solids and liquid holdups were lower in the central region and increased radially towards the wall. Gas holdup decreased with increasing solids circulation rate but opposite trend was observed for solids holdup. Solids circulation rate had negligible effect on liquid holdup at lower axial locations compared to top of the riser. Cross-sectional average of solids, gas and liquid holdups did not change significantly at higher liquid superficial velocities. 相似文献