A numerical study of the influence of pre-wetting on the static liquid hold-up and wetting efficiency in a trickle bed reactor

Trickle beds are widely used in chemical processes due to their significant advantages over other multiphase reactors. However, their operation presents challenges, primarily due to complex hydrodynamic characteristics. One of the most critical challenges is the non-uniform liquid distribution, which leads to inhomogeneous particle wetting and possible adverse effects on process yield and selectivity. In this study, the effects of initial wetting conditions on static liquid hold-up and wetting efficiency were studied using particle-resolved Direct Numerical Simulation (DNS). Our results reveal that the local distribution of initial wetting significantly influences the liquid pathways after start-up, enhancing wetting efficiency compared to that of an initially dry bed. Local variations in pre-wetted beds, however, have minimal impact on wetting efficiency, particularly at high liquid fluxes. Notably, liquid flux plays a more significant role in determining the wetting efficiency of pre-wetted beds.