Abstract: Membrane distillation technology has exhibited great application prospects in the recovery and treatment of desulfurization wastewater from coal-fired power plants because of its applicability under low temperature conditions and high recycling water quality. In this paper, the heat and mass transfer of a new conductive gap membrane distillation (CGMD) with condensing microstructure is theoretically analyzed. Based on the present theories, the heat and mass transfer on the hot side of the membrane and the heat transfer after the condensing microstructure added into the gap are taken into consideration. Then the selection of mass transfer models with different pore sizes and temperatures for the mechanism of mass transfer across the membrane in microporous membranes has been emphatically analyzed. Finally, the influence of temperature and pore size on the selection of transmembrane mass transfer model is illustrated by corresponding experiments such that the experimental results are obtained and then verified to be mostly consistent with the theoretical analysis results.

Key words: condensation microstructure, conductive gap membrane distillation, membrane module, heat and mass transfer mechanism, mathematical model