Effect of gas density on hydrodynamic characteristics and gas-liquid interfacial area in a 5 kW bubble column reactor

This study investigated the impact of gas density on the hydrodynamic characteristics and gas-liquid interfacial area within a bubble column reactor, utilizing air, helium, and tap water. The performance of two types of distributors was compared. Key parameters such as gas holdup, transition gas holdup, transition velocity, bubble size, and specific interfacial area were analyzed across various gas velocities, pressures, and helium concentrations in the air-helium mixtures. As the gas density increased, the gas holdup, transition gas holdup, and transition velocity increased. The porous-plate distributor exhibited better performance metrics than the tube-type distributor. Furthermore, power-law relationships were derived for various parameters in both homogeneous and heterogeneous regimes. In the homogeneous regime, gas velocity exerted a more substantial influence on the gas holdup and specific interfacial area than gas density, whereas in the heterogeneous regime, both factors had nearly equivalent influences.