Characteristics of Liquid Phase Backmixing in Gas–Liquid–Solid Mini-Fluidized Beds with Varied Pressure and Temperature

The gas–liquid–solid mini-fluidized bed is a novel multiphase reactor. It is important to comprehend how the behavior of liquid phase backmixing changes with temperature and pressure, which affects reactor design, scale-up, and optimal operation and control. This study experimentally evaluates the residence time distribution (RTD) of the liquid phase in a 10 mm diameter gas–liquid–solid mini-fluidized bed using the pulsed tracer method. The findings indicate that the backmixing reduces as the static bed height, liquid surface viscosity, and pressure drop as the liquid velocity, system temperature, and particle size rise. As the gas velocity increases, the liquid backmixing initially drops and then increases, and the ideal operating gas velocity is 21 mm/s. The RTD of the liquid phase in the fluidized bed under small bed diameter conditions is also examined. The Peclet number under 3 mm bed diameter conditions is substantially greater than those under other situations, which is near the plug flow.