Abstract:

In the investigations of fluidization in recent 100 years, different diameters of fluidized bed are involved. However, most of these studies took the large-scale fluidized bed as the research goal, and did not focus on the characteristics of mini or micro fluidized beds. Therefore, the research and understanding of mini- or micro-fluidized bed is very limited. Fluidized bed, as a special unit operation process and installation to deal with solid particles, its miniaturization has both the advantages of micro channel reactor and macro scale fluidized bed, and is an important research direction of fluidization. The progress of gas-solid micro fluidized bed has been well reviewed. In this review, the research progress of liquid-solid and gas-liquid-solid mini- or micro-fluidized beds is reviewed. The contents of research progress are as follows. When the bed diameter of liquid-solid micro-fluidized bed decreases, the wall effect increases, and measured minimum fluidization liquid velocity is greater than that calculated by Ergun formula; Richardson-Zaki equation describing the law of uniform expansion and fluidization of liquid-solid flow needs to be modified. There are four typical flow patterns in gas-liquid-solid micro fluidized bed: semi-fluidization, slug flow, dispersed bubbling flow and liquid transport flow. Due to the decrease of bed diameter and semi-fluidization, the minimum fluidization liquid velocity cannot be determined according to the pressure drop velocity curve. The reaction performance of gas-liquid-solid micro fluidized bed has been effectively improved. Further research directions are pointed out, so as to provide some reference for the researchers.

Key words: gas-liquid-solid, fluidization, fluidized-bed, microreactor, progress

摘要：

在百年流态化的研究过程中，涉及到直径不同的流化床。但是，多以流化床的大型化为研究目标，对微型流化床及其本身特性的研究很少。作为专门处理固体颗粒的流态化单元过程，其装置的微型化将兼具微通道反应器和宏观流化床各自的优点，是流态化研究的重要方向。鉴于气固微型流化床已有全面的国内外进展综述，本文仅对液固和气液固微型流化床的国内外研究进展进行分析。结论性内容包括：液固微型流化床床径减小，壁面效应增强，最小流化液速实验值大于Ergun公式计算值；需对描述液固均匀膨胀流化规律的Richardson-Zaki方程加以修正。气液固微型流化床内存在4种典型流型：半流化、弹状流、分散鼓泡流和液体输送流；由于床径减小，出现半流化状态，依据压降表观液速关系曲线等无法确定最小流化液速；气液固微型流化床的反应性能得以有效提升；最后给出了进一步研究的方向，以期为后续研究提供参考。

关键词: 气液固, 流态化, 流化床, 微反应器, 进展