Effects of Membrane Morphology on the Efficiency of Direct Contact Membrane Distillation

A computer simulation is used to predict the effects of membrane morphology on the thermal efficiency of direct contact membrane distillation. The mass transfer through the porous microstructure and the heat conduction through the membrane are both related by the membrane morphology. The interrelated tortuosity of the porous structure and solid phase influences the mass transfer and thermal conductivity, respectively. The effects of varying the morphology are elucidated and introducing a lattice structure, which tailors the morphology, can significantly increase thermal efficiency. A three-layer system is also simulated, where the pore size in the middle layer can be increased without significantly increasing the risk of membrane pore wetting. Three-layer systems that possess a lattice morphology are found to result in thermal efficiencies around 20\% higher than random morphologies.