湍流床稠密气固流中介尺度流动结构的识别与表征

项目名称： 湍流床稠密气固流中介尺度流动结构的识别与表征

项目编号： No.91534111

项目类型： 重大研究计划

立项/批准年度： 2016

项目学科： 有机化学

项目作者： 刘梦溪

作者单位： 中国石油大学（北京）

项目金额： 64万元

中文摘要： 湍流床反应器在石油化工中具有广泛的用途，对介尺度流动结构认识不清是反应器内传递受限和产率低下的主要原因。湍流床内稠密气固流的介尺度流动结构是在气体输入能耗最低和颗粒势能最低妥协机制控制下而形成的稳定状态，申请者前期的探索性研究表明，稠密气固流中存在大量颗粒聚团，聚团内部处于未流化状态，稳定状态可以用一个含有颗粒的气泡、乳化相和颗粒聚团三结构模型来描述。本课题主要针对重大研究计划中第2个核心科学问题而展开，拟通过多种方法对高度耦合的光纤和压力脉动信号分别进行解耦，找到准确的气泡—密相信号识别方法，提出颗粒聚团的定义和判别依据，最终解决介尺度结构的识别、定量表征和颗粒聚团当量直径预测的关键科学问题，并对操作条件和颗粒性质对气泡和颗粒聚团的固含率、尺寸分布、运动速度等参数的影响进行分析和关联。研究结果有利于揭示湍流床稠密气固流反应器中介尺度结构对流动、传递与反应的影响规律。

中文关键词： 流态化；介尺度流动结构；颗粒聚团；稠密气固两相流；多尺度

英文摘要： The turbulent fluidized bed reactors have been widely used in chemical and petrochemical processes. The lack of knowledge on meso-scale flow structure in these reactors has considerably restricted the mass and heat transfer and reduced the yield. In a dense gas-solid flow of a turbulent fluidized bed, a stable flow structure is achieved resulting from the compromise of minimal input energy per unit mass of the particles and smallest potential energy of the particles. Exploratory experiment result shows that there exist a lot of particle agglomerates in the dense phase and particles inside the agglomerate are unfluidized. Such phenomenon suggests that the stable flow structure can be described by a physical model with respect to three meso-scale flow structures: bubbles with particles inside, the emulsion phase and particle agglomerates. This project aims for resolution of the second key scientific problem of the guide by using multi methods, such as decoupling optical fiber fluctuation signals and pressure fluctuation, suggesting an accurate approach to identify the bubble and the dense phase in signals, proposing the definition and the distinguish basis of the agglomerates. By using these methods, the project is designed to resolve the key scientific problems with respect to identification and quantitive characterization of meso-scale flow structures and prediction model of the equivalent diameter of agglomerates. The influence of operating condition and particle physical property on solid holdup, size distribution as well as immigration velocity of bubbles and afflomerates is evaluated and related. Results of this project will facilitate the revelation of the influence of meso-scale flow structure on mass and heat transfer and reaction inside the turbulent fluidized bed reactors.

英文关键词： fluidization;meso-scale flow structure;particle agglomerates;dense gas-solid two-phase flow;multi-scale