An induction heating fluidized bed with liquid injection was designed to mimic the exothermic process of particles in industrial olefin polymerization fluidized beds. The effects of liquid injection flow rate on agglomeration behaviors were investigated through the characterization of agglomerate size and mass. Agglomeration mechanisms were proposed based on the experimental data of bed pressure drop, axial temperature distribution, and microscale visualization. Results have revealed that, with the increase of liquid injection flow rate, the agglomeration mechanism was controlled by the solid bridge force, the liquid bridge force, and the cooperative action of them, respectively. Wet agglomerates caused by the liquid bridge force induced local dead zones and provided a good environment for the occurrence of a hot spot and growth of solid bridge, and thus the formation of solid agglomerates. Besides, elevating the liquid injection position and increasing the induction heating power can widen the operation range of the liquid injection flow rate for fluidized bed reactors.

An image analysis method was developed based on deep-learning algorithms to extract phase fractions quantitatively in a rectangular trickle bed, and the average identification error was lower than 5%. Furthermore, the flow regime transition in the trickle bed was studied. In trickle-to-pulse flow transition, the trickle flow could be further classified into the stable trickle flow and accelerated one. The SD of liquid fractions and the peak width at half-height of the probability density curve of liquid fractions were close to zero in stable trickle flow, increased rapidly in accelerated trickle flow, and remained approximately constant in pulse flow. In bubble-to-pulse flow transition, dispersed bubbles in bubble flow induced the outliers outside the upper boundary of the boxplot of gas fraction, while alternative appearance of gasrich zone and liquid-rich zone in pulse flow induced outliers outside both the upper and lower boundaries of the boxplot of gas fraction.

Particle agglomeration induced by liquid bridge force widely exists in industrial fluidization processes involving liquid spray. To understand the agglomeration mechanism, a cold-mode fluidized bed loaded with wax-coated graphite particles is constructed and heated by an electromagnetic induction method. In the experiments, the wet agglomerate mass is obtained online through the pressure drop measurement and the heat conservation relationship. Besides, an energy balance model is proposed based on the kinetic energy of rebounding of wet particles and the dissipation energy of liquid bridge to further study the evolution of liquid-induced agglomerates via a Monte Carlo method. The simulation and experimental results agree well and indicate that the agglomerate mass decreases with the particle exothermic rate and superficial gas velocity and increases with the liquid injection rate. This work provides an effective method for online characterization of wet agglomerates and is beneficial for the stable operation of industrial fluidized-bed reactors.

Based on a self‐established cold‐flow experimental device, the pressure drop in a cocurrent downflow three‐phase moving bed was investigated under a wide range of gas, liquid, and solid flow rates during dynamic and steady‐state operation. The results showed that for the startup of the bed, since the first bed layer packed by fall‐falling of particles had lower voidage, it would take at least one bed volume time to make the voidage in the bed reach the steady‐state. Under steady‐state conditions, the pressure drop increased with the increase of gas and liquid mass flow rates, liquid viscosity, and decreased with the increase of solid flow rate. Furthermore, it was found that the liquid distribution became more uniform due to particle movement. The experimental data obtained in this study was used to develop a correlation to predict the pressure drop in a three‐phase moving bed with an average relative error of 9.32%.