It is discussed how Computational Fluid Dynamics (CFD) can be used for hydrodynamics calculations within structured packings. Three dimensional (3D) simulations, in which the influence of mesh size and turbulence models were tested, have been carried out for dry pressure drop determination. Two dimensional (2D) Volume of Fluid gas-liquid flow simulations have been used for liquid holdup determination. Numerical results are compared to tomographic liquid holdup measurements. Then, a comparison with data from a gas treatment pilot plant shows that wet pressure drop can be predicted by combining these two types of information (dry pressure drop and liquid holdup).