Transition identification between slurry bed and fluidized bed modes for gas-liquid-solid reactor systems

Two types or operating modes of gas-liquid-solod three-phase flow reactors, slurry bed and fluidized bed, are widely used in chemical industry. Early they were distinguished by the size and density of solid particles and the distribution of axial solid holdup. With the development of modern multiphase flow measurement technology and the requirement of chemical reaction to control multiphase flow more accurately, it is necessary to study the classification of multiphase flow reactors more carefully. In this paper, acceleration vibration signal detection and telecentric photography are used to study the classification criteria of reactor types. The acceleration vibration time series signals at different axial positions of the three-phase reactor are measured by high-precision acceleration sensors and their standard deviation and power spectral density (PSD) are analyzed. Combined the telecentric image visualization results, the operating modes and their transitions are identified and confirmed, and the fine classification criterion of the two operation modes is obtained. When the superficial liquid velocity is 0.01 m/s and no gas is input, the transition boundary between liquid-solid slurry-like bed and fluidized bed is particle size 150 mesh (100 μm); when the superficial liquid velocity is 0.01 m/s and the superficial gas velocity is 0.0033 m/s, the transition boundary between slurry bed and fluidized bed is particle size 80 mesh (180 μm). These findings provide useful guidance for the accurate control of three-phase flows and reactions.