Particle-resolved CFD simulations of local bubble behaviors in a mini-packed bed with gas–liquid concurrent flow

Abstract

• Particle-resolved CFD method is established with good model reliability. • The local bubble behaviors in packed bed are numerically investigated. • Gas residence time can be adjusted by controlling flow rate and packing wettability. • Gas phase is more evenly distributed in the packed bed with hydrophobic particles. The controlling of residence time and gas–liquid interface distribution is critical issue in operating packed bed reactors with gas–liquid concurrent upflow. Herein, gas–liquid interface in the particle-resolved packed bed is calculated with the Volume of Fluid (VOF) method. The influences of flow rate, bed supporting wire, packing wettability and surface tension on gas–liquid upflow in a mini-packed bed are studied. The periodic bubble flow behavior at bed bottom is observed due to bubble coalescence. Increasing superficial liquid and gas velocity can shorten the time needed for bubble traveling through the bed and increase the pressure drop. The supporting wires aggravate the degree of bubbles coalescence and slightly increase the residence time of the gas phase. The hydrophobic packing can promote the uniform distribution of the gas–liquid interface and greatly increase the gas–liquid interface area. The bubble behavior in the packed bed can be changed by manipulating liquid surface tension.