The theoretical model has been proposed to describe a liquid-gap membrane distillation process (LMD) in LMD-module. The analytical expression for transmembrane flux in a real LMD-module has been derived. The impact of membrane characteristics and experimental conditions on the permeate flux has been analyzed. The LMD-module, based on this theoretical model, was designed. The influence of the solution temperature, the feed flow rate on the LMD-module productivity has been studied experimentally using the hydrophobic microporous membrane "Vladipore". Good agreement is found between the theoretical and the experimental values of the LMD process.