Numerical study of liquid coverage in a gas-liquid-solid packed bed

In this work, computational fluid dynamics (CFD) simulations using the volume-of-fluid (VOF) model were employed to investigate the effects of liquid properties, liquid and gas flow rates, and wettability of particles on liquid maldistribution at the microscopic level in a fixed bed reactor. The simulation results show that the number of wetted particles decreases with increasing gas velocity, consequently leading to lower liquid-solid contact areas. The radial liquid distribution is greatly enhanced by increasing the liquid flow rate, whereas the time for the liquid to pass through the whole bed is decreased, as expected. Based on simulation results, it was found that the liquid-solid contact area can be increased by using liquids of high viscosities and more wettable particles. However, the flow-through time increases with increasing liquid viscosity. An increase in the gas density showed a minimal impact on the liquid flow-through time, and the liquid density does not impact the radial liquid distribution or the liquid flow time within a range of liquid densities typically encountered in the petrochemical industry. (C) 2015 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.