Flow nonuniformity effects on catalyst effectiveness in particle‐scale trickle‐bed reaction–transport coupling

In trickle‐bed reactors, flow nonuniformity and wetting heterogeneity strongly affect mass transfer and catalyst effectiveness. A coupled CFD model was developed at the local packed‐bed scale for DMT hydrogenation to investigate the effects of wetting behavior, flow distribution, catalyst geometry, and multi‐particle interactions. Under isolated particle conditions, the relationship between internal effectiveness factor and Thiele modulus was established for complete and partial wetting states, and empirical correlations incorporating wetting fraction were developed with high accuracy ( R 2 = 0.9984 and 0.9974; MAPE = 2.50% and 3.21%). External flow simulations revealed that local velocity variations generated surface concentration heterogeneity and diffusion limitations, which were alleviated by increasing liquid velocity. Trilobe catalysts improved internal diffusion but introduced additional external transport resistance. In multi‐particle systems, interparticle liquid retention weakened downstream reactant transport and caused a progressive decline in effectiveness factor. These findings provide insights into catalyst design and operating optimization in trickle‐bed reactors.