When developing tailored porous media, accurate assessment of the flow characteristics is essential. A numerical simulation is an effective method characterizing the properties of porous media, provided it precisely evaluates the effect of the structure of the porous medium. A lattice Boltzmann method (LBM) is expected to be a relevant tool to predict flows through such geometrically complex flow fields. Knowing the structure of the medium obtained from various steps of phase separation process of a binary mixture, it is examined through LBM simulations how the structure affects the bulk properties of porous media which include dead-end flow passages as well. After validating the accuracy of the method by comparing the simulated permeability data with experimental or empirical ones for packed beds of homogeneous spheres, the permeability of inhomogeneous porous media is related mainly to specific surface areas.