关键词: 气液固, 流态化, 流化床, 微反应器, 进展

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