Investigation on mixing performance of the mini-fluidized bed

Mini-fluidized beds (MFBs) can significantly enhance the mass transfer, heat transfer and mixing process. In this study, planar laser induced fluorescence method (PLIF) was used to evaluate the mixing performance in liquid-solid mini-fluidized beds. In contrast to the particle-free tubes, the relative mixing index, mixing length, mixing time, specific power consumption, mixing effectiveness and energy efficiency of mini-fluidized beds with inner diameters of 1–3 mm were analyzed. The relative mixing index of the mini-fluidized beds is 3.07–9.55 times that of the particle-free tubes under the same conditions, and the mixing length and time are reduced by 45.11% ∼ 99.59%. When the bed-to-particle diameter ratio is 13.86, the optimal operating voidage is about 0.76, which corresponds to the maximum mixing effectiveness and mixing energy efficiency. The mixing enhancement of the mini-fluidized bed system was evaluated, which provides a theoretical basis for the new application of microstructures in mini-fluidized bed reactors.