Zero-gravity distillation (ZGD) is one of the few ways to establish a small-scale distillation process. In contrast to conventional distillation columns, capillary forces, e.g. induced by metal foams, are exploited to ensure liquid flow in ZGD units. In order to strengthen the knowledge basis necessary for the ZGD equipment design, understanding of the relevant transport phenomena is necessary. In this work, a model for phenomena governing the ZGD processes was developed. It includes momentum, heat and species transport in both liquid and vapour phases. Evaporation and condensation impacts on momentum transfer are captured in a simplified manner, allowing an approximate local flow velocity determination. The developed model was implemented in the OpenFOAM® software and used to numerically simulate methanol/ethanol distillation processes in 2D approximation. In a first numerical study, the influence of the metal foam porosity and thickness on the velocity, temperature and mass fraction fields was numerically investigated.